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Sample records for inositol phospholipids precedes

  1. Dictyostelium uses ether-linked inositol phospholipids for intracellular signalling.

    PubMed

    Clark, Jonathan; Kay, Robert R; Kielkowska, Anna; Niewczas, Izabella; Fets, Louise; Oxley, David; Stephens, Len R; Hawkins, Phillip T

    2014-10-01

    Inositol phospholipids are critical regulators of membrane biology throughout eukaryotes. The general principle by which they perform these roles is conserved across species and involves binding of differentially phosphorylated inositol head groups to specific protein domains. This interaction serves to both recruit and regulate the activity of several different classes of protein which act on membrane surfaces. In mammalian cells, these phosphorylated inositol head groups are predominantly borne by a C38:4 diacylglycerol backbone. We show here that the inositol phospholipids of Dictyostelium are different, being highly enriched in an unusual C34:1e lipid backbone, 1-hexadecyl-2-(11Z-octadecenoyl)-sn-glycero-3-phospho-(1'-myo-inositol), in which the sn-1 position contains an ether-linked C16:0 chain; they are thus plasmanylinositols. These plasmanylinositols respond acutely to stimulation of cells with chemoattractants, and their levels are regulated by PIPKs, PI3Ks and PTEN. In mammals and now in Dictyostelium, the hydrocarbon chains of inositol phospholipids are a highly selected subset of those available to other phospholipids, suggesting that different molecular selectors are at play in these organisms but serve a common, evolutionarily conserved purpose.

  2. Rabbit synoviocyte inositol phospholipid metabolism is stimulated by hydroxyapatite crystals

    SciTech Connect

    Rothenberg, R.J.; Cheung, H.

    1988-04-01

    Inhibition of prostaglandin E2 synthesis partially ameliorates some aspects of synovitis, but joint destruction still progresses. Other aspects of phospholipid metabolism may play a role in synovial tissue pathophysiology. Products of phosphatidylinositol metabolism can activate intracellular processes in response to extracellular stimuli. We asked whether this pathway is activated in synoviocytes in monolayer tissue culture by the addition of hydroxyapatite (HA) crystals in medium. These crystals are found in pathological human synovial fluid. These crystals are associated with the secretion of degradative enzymes and with a destructive arthritis in humans. Rabbit synoviocyte cultures, previously incubated with (3H)inositol to label inositol phospholipids, were stimulated with the addition of hydroxyapatite (180 micrograms/ml) to the cultures. There was enhanced intracellular accumulation of (3H)inositol monophosphate (30-100%) after 4 h. This indicated an increased phospholipase C activity. The radioactivity in (3H)inositol bis- and trisphosphates was too low to reliably measure. The use of (32P)Pi allowed detection of these compounds. In the presence of HA, incorporation of (32P)Pi into phosphatidylinositol, phosphatidylinositol monophosphate, and phosphatidylinositol bisphosphate was increased. In addition, cultures exposed to (32P)Pi during stimulation with HA had an increased content of (32P)inositol monophosphate, bisphosphate, and trisphosphate.

  3. Structural analysis of inositol phospholipids from Trypanosoma cruzi epimastigote forms.

    PubMed Central

    Bertello, L E; Gonçalvez, M F; Colli, W; de Lederkremer, R M

    1995-01-01

    Inositol phospholipids (IPL) from epimastigote forms of Trypanosoma cruzi have been investigated by metabolic labelling with [3H]palmitic acid and by GLC-MS analysis of the lipids obtained from non-labelled parasites. The IPL fraction was separated into phosphatidylinositol (PI) and inositol-phosphoceramide subfractions, the latter accounting for 80-85% of the total IPL. The neutral lipids released from the IPLs by PI-specific phospholipase C (PI-PLC) from Bacillus thuringiensis were analysed by silica-gel and reverse-phase TLC for the radioactive lipids and by GLC-MS for the non-radioactive samples. Ceramides containing dihydrosphingosine and sphingosine with C16:0 and C18:0 fatty acids were identified. The main component in the [3H]palmitic acid-labelled ceramides was palmitoyldihydrospingosine, while in the non-labelled sample the ceramides contained mainly sphingosine. This could reflect partial uptake of phospholipid from the medium. The PI contain both alkylacyl- and diacyl-glycerol lipids, with the ether lipid being more abundant. The latter was identified as 1-O-hexadecylglycerol esterified by C18:2 and C18:1 fatty acids. Interestingly, the same lipid had been identified in the anchor of the 1G7 glycoprotein of T. cruzi metacyclic forms. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 PMID:7646454

  4. Insulin stimulates the biosynthesis of chiro-inositol-containing phospholipids in a rat fibroblast line expressing the human insulin receptor.

    PubMed Central

    Pak, Y; Paule, C R; Bao, Y D; Huang, L C; Larner, J

    1993-01-01

    HIRc-B cells (rat fibroblasts expressing the human insulin receptor) were incubated with myo-[3H]inositol for 48 hr, and the biosynthesis of chiro-[3H]inositol was investigated in the absence and presence of insulin following a time course up to 60 min. After phase separation, treatment with insulin for 15 min caused a 2.2-fold increase in the specific radioactivity of chiro-[3H]inositol-containing phospholipids in contrast to a 1.2-fold increase in the specific radioactivity of myo-[3H]inositol-containing phospholipids. No insulin-mediated change in the specific radioactivity was observed in the inositol phosphates or free inositols. Further detailed analysis of individual [3H]inositol-containing phospholipids demonstrated marked increases in specific activity of the chiro-[3H]inositol phospholipids after 15 min of incubation with insulin: phosphatidylinositol 4-phosphate and 4,5-bisphosphate, 4.2-fold; lysophosphatidylinositol, 1.5-fold; phosphatidylinositol, 3.2-fold. In contrast, myo-[3H]inositol-containing phospholipids demonstrated relatively small increases (1.1- to 1.4-fold) after 5 min of incubation with insulin. These findings indicate that insulin stimulates de novo synthesis of chiro-inositol-containing phospholipids at the inositol phospholipid level. Images Fig. 2 Fig. 3 PMID:8356081

  5. Metabolism of the phospholipid precursor inositol and its relationship to growth and viability in the natural auxotroph Schizosaccharomyces pombe.

    PubMed Central

    Fernandez, S; Homann, M J; Henry, S A; Carman, G M

    1986-01-01

    Phospholipid metabolism in the fission yeast Schizosaccharomyces pombe was examined. Three enzymes of phospholipid biosynthesis, cytidine diphosphate diacylglycerol synthase (CDP-DG), phosphatidylinositol (PI) synthase, and phosphatidylserine (PS) synthase, were characterized in extracts of S. pombe cells. Contrary to an earlier report, we were able to demonstrate that CDP-DG served as a precursor for PI and PS biosynthesis in S. pombe. S. pombe is naturally auxotrophic for the phospholipid precursor inositol. We found that S. pombe was much more resistant to loss of viability during inositol starvation than artificially generated inositol auxotrophs of Saccharomyces cerevisiae. The phospholipid composition of S. pombe cells grown in inositol-rich medium (50 microM) was similar to that of S. cerevisiae cells grown under similar conditions. However, growth of S. pombe at low inositol concentrations (below 30 microM) affected the ratio of the anionic phospholipids PI and PS, while the relative proportions of other glycerophospholipids remained unchanged. During inositol starvation, the rate of PI synthesis decreased rapidly, and there was a concomitant increase in the rate of PS synthesis. Phosphatidic acid and CDP-DG, which are precursors to these phospholipids, also increased when PI synthesis was blocked by lack of exogenous inositol. The major product of turnover of inositol-containing phospholipids in S. pombe was found to be free inositol, which accumulated in the medium and could be reused by the cell. Images PMID:3011744

  6. Phospholipid biosynthesis in Candida albicans: Regulation by the precursors inositol and choline

    SciTech Connect

    Klig, L.S.; Friedli, L.; Schmid, E. )

    1990-08-01

    Phospholipid metabolism in the pathogenic fungus Candida albicans was examined. The phospholipid biosynthetic pathways of C. albicans were elucidated and were shown to be similar to those of Saccharomyces cerevisiae. However, marked differences were seen between these two fungi in the regulation of the pathways in response to exogenously provided precursors inositol and choline. In S. cerevisiae, the biosynthesis of phosphatidylcholine via methylation of phosphatidylethanolamine appears to be regulated in response to inositol and choline; provision of choline alone does not repress the activity of this pathway. The same pathway in C. albicans responds to the exogenous provision of choline. Possible explanations for the observed differences in regulation are discussed.

  7. Expression of the Saccharomyces cerevisiae inositol-1-phosphate synthase (INO1) gene is regulated by factors that affect phospholipid synthesis.

    PubMed Central

    Hirsch, J P; Henry, S A

    1986-01-01

    The INO1 gene of Saccharomyces cerevisiae encodes the regulated enzyme inositol-1-phosphate synthase, which catalyzes the first committed step in the synthesis of inositol-containing phospholipids. The expression of this gene was analyzed under conditions known to regulate phospholipid synthesis. RNA blot hybridization with a genomic clone for INO1 detected two RNA species of 1.8 and 0.6 kb. The abundance of the 1.8-kb RNA was greatly decreased when the cells were grown in the presence of the phospholipid precursor inositol, as was the enzyme activity of the synthase. Complementation analysis showed that this transcript encoded the INO1 gene product. The level of INO1 RNA was repressed 12-fold when the cells were grown in medium containing inositol, and it was repressed 33-fold when the cells were grown in the presence of inositol and choline together. The INO1 transcript was present at a very low level in cells containing mutations (ino2 and ino4) in regulatory genes unlinked to INO1 that result in inositol auxotrophy. The transcript was constitutively overproduced in cells containing a mutation (opi1) that causes constitutive expression of inositol-1-phosphate synthase and results in excretion of inositol. The expression of INO1 RNA was also examined in cells containing a mutation (cho2) affecting the synthesis of phosphatidylcholine. In contrast to what was observed in wild-type cells, growth of cho2 cells in medium containing inositol did not result in a significant decrease in INO1 RNA abundance. Inositol and choline together were required for repression of the INO1 transcript in these cells, providing evidence for a regulatory link between the synthesis of inositol- and choline-containing lipids. The level of the 0.6-kb RNA was affected, although to a lesser degree, by many of the same factors that influence INO1 expression. Images PMID:3025587

  8. Comparison of muscarine- and vasopressin-stimulated inositol phospholipid metabolism in the superior cervical ganglion of the rat

    SciTech Connect

    Horwitz, J.; Anderson, C.; Perlman, R.L.

    1986-03-05

    Both muscarine and vasopressin have previously been shown to increase the accumulation of /sup 3/H-inositol phosphates (/sup 3/H-IP) in superior cervical ganglia in which the phospholipids were labeled with /sup 3/H-inositol. They have compared the effects of muscarine and vasopressin on phospholipid metabolism in the ganglion. The effects of these agents on /sup 3/H-IP accumulation are additive. The response to muscarine plateaus after approximately 10 min whereas the response to vasopressin increases for at least 30 min. Decentralization and maintenance in organ culture appear to potentiate the effect of muscarine on /sup 3/H-IP accumulation but do not effect the response of the ganglia to vasopressin. Muscarine and vasopressin also increase the incorporation of /sup 3/H-inositol into phospholipids in the ganglion. Autoradiographic techniques were used to localize the inositol-containing phospholipids in the ganglion. Muscarine increases phospholipid labeling primarily in the cell bodies of the principal ganglionic neurons, whereas vasopressin increases phospholipid labeling primarily in the neuropil. These data are consistent with the hypothesis that muscarine and vasopressin stimulate the metabolism of different pools of phospholipids.

  9. [Activity of the inositol-containing phospholipid dimer analogues against human immunodeficiency virus].

    PubMed

    Baranova, E O; Shastina, N S; Lobach, O A; Chataeva, M S; Nosik, D N; Shvets, V I

    2014-01-01

    For the purpose of finding effective inhibitors of virus adsorption the series of inositol-containing phospholipid dimer analogues were previously synthesized. In the present work, the antiretroviral activity of these compounds against HIV-1 was demonstrated on the model of cells infected with the virus. The highest effect was found in the case of dimer poliol 5, EC50 (50%-effective concentration) was 3.9 microg/ml. The development of new polyanionic compounds, which can interfere with early steps of the virus life cycle, is a promising addition to the antiretroviral therapy based on the virus enzyme inhibitors.

  10. Studies on the biochemistry and physiology of inositol phospholipids in Dunaliella salina

    SciTech Connect

    Einspahr, K.J.

    1988-01-01

    In the unicellular alga, Dunaliella salina, phosphatidylinositol, phosphatidylinositol 4-phosphate (PIP), and phosphatidylinositol 4,5-bisphosphate (PIP{sub 2}) comprise 14.8, 1.2, and 0.3 mol %, respectively, of cellular phospholipids. In isolated plasma membrane fractions, PIP and PIP{sub 2} are highly concentrated, together comprising 9.5 mol % of plasmalemma phospholipids. The metabolism of these inositol phospholipids and phosphatidic acid (PA) is very rapid under normal growth conditions, as illustrated by the fact that within 5 minutes after introduction of {sup 32}P{sub i} into the growth medium over 75% of lipid-bound label was found in these quantitatively minor phospholipids. Within 2 minutes after a sudden hypoosmotic shock, the levels of PIP{sub 2} and PIP dropped to 65 and 79%, respectively, of controls. Within the same time frame PA rose to 141% of control values. These data suggest that a rapid breakdown of the polyphosphoinositides may mediate the profound morphological and physiological changes which allow this organism to survive drastic hypoosmotic stress.

  11. Cyclic AMP restores a normal phenotype to sis oncogene transformed cells and inhibits inositol phospholipid turnover

    SciTech Connect

    Murphy, S.K.; Lazarus, A.; Pendergas, M.; Lockwood, A.H.

    1987-05-01

    The sis oncogene encodes the A chain of platelet-derived growth factor (PDGF). NIH3T3 fibroblasts transfected with the cloned sis oncogene display a malignant phenotype and have enhanced turnover of the regulatory phospholipid phosphatidylinositol 4,5 biphosphate (PIP2). They have found that elevation of intracellular cyclic AMP can restore many aspects of normal growth and morphology to sis-transformed cells. Cells rapidly become less refractile, flatten on the substratum, develop actomyosin bundles, and acquire a more tranquil membrane. Growth rate and saturation density are reduced. Cultures become contact-inhibited and, at confluence, assume a normal fibrobastic morphology. The ability to grow in low serum or suspension is lost. Following addition of 8-Br-cAMP, cellular levels of PIP and PIP2 increase to those in untransformed cells. Concurrently, the steady-state levels of inositol phosphates are reduced to normal values. They have found a similar effect of cAMP on inositol phospholipid metabolism in cells transformed by the human H-ras oncogene. These results suggest that cAMP, acting through the cAMP-dependent protein kinase, antagonizes ras and sis oncogene expression by inhibiting polyphosphoinositide turnover. Such action might occur by phosphorylation of the PDGF (sis) receptor or of a ras-stimulated phospholipase C.

  12. Ethanol stimulates phospholipid turnover and inositol 1,4,5-trisphosphate production in Chlamydomonas eugametos gametes.

    PubMed

    Musgrave, A; Kuin, H; Jongen, M; de Wildt, P; Schuring, F; Klerk, H; van den Ende, H

    1992-02-01

    Alcohols induce mating-structure activation in Chlamydomonas eugametos gametes. From the effect of ethanol on the (32)P-labelling of polyphosphoinositides, we conclude that the synthesis of these lipids is stimulated. Biologically inactive concentrations of ethanol (<6%) had no effect on synthesis, but 6-8% ethanol stimulated synthesis for upto 60 min. The (32)P incorporated into polyphosphoinositides and phosphatidic acid during ethanol treatment was readily chased out when 1 mM unlabelled Na3PO4 was added. Using a binding assay for inositol 1,4,5-trisphosphate, we show that the production of this phospholipid constituent is dramatically increased after ethanol treatment. This effect, coupled to a rise in intracellular calcium concentration, could explain gamete activation. The significance of these results in explaining other ethanol-induced phenomena in algae is discussed.

  13. Transient and sustained increases in inositol 1,4,5-trisphosphate precede the differential growth response in gravistimulated maize pulvini

    NASA Technical Reports Server (NTRS)

    Perera, I. Y.; Heilmann, I.; Boss, W. F.; Davies, E. (Principal Investigator)

    1999-01-01

    The internodal maize pulvinus responds to gravistimulation with differential cell elongation on the lower side. As the site of both graviperception and response, the pulvinus is an ideal system to study how organisms sense changes in orientation. We observed a transient 5-fold increase in inositol 1,4,5-trisphosphate (IP3) within 10 s of gravistimulation in the lower half of the pulvinus, indicating that the positional change was sensed immediately. Over the first 30 min, rapid IP3 fluctuations were observed between the upper and lower halves. Maize plants require a presentation time of between 2 and 4 h before the cells on the lower side of the pulvinus are committed to elongation. After 2 h of gravistimulation, the lower half consistently had higher IP3, and IP3 levels on the lower side continued to increase up to approximately 5-fold over basal levels before visible growth. As bending became visible after 8-10 h, IP3 levels returned to basal values. Additionally, phosphatidylinositol 4-phosphate 5-kinase activity in the lower pulvinus half increased transiently within 10 min of gravistimulation, suggesting that the increased IP3 production was accompanied by an up-regulation of phosphatidylinositol 4, 5-bisphosphate biosynthesis. Neither IP3 levels nor phosphatidylinositol 4-phosphate 5-kinase activity changed in pulvini halves from vertical control plants. Our data indicate the involvement of IP3 and inositol phospholipids in both short- and long-term responses to gravistimulation. As a diffusible second messenger, IP3 provides a mechanism to transmit and amplify the signal from the perceiving to the responding cells in the pulvinus, coordinating a synchronized growth response.

  14. Transient and sustained increases in inositol 1,4,5-trisphosphate precede the differential growth response in gravistimulated maize pulvini

    NASA Technical Reports Server (NTRS)

    Perera, I. Y.; Heilmann, I.; Boss, W. F.; Davies, E. (Principal Investigator)

    1999-01-01

    The internodal maize pulvinus responds to gravistimulation with differential cell elongation on the lower side. As the site of both graviperception and response, the pulvinus is an ideal system to study how organisms sense changes in orientation. We observed a transient 5-fold increase in inositol 1,4,5-trisphosphate (IP3) within 10 s of gravistimulation in the lower half of the pulvinus, indicating that the positional change was sensed immediately. Over the first 30 min, rapid IP3 fluctuations were observed between the upper and lower halves. Maize plants require a presentation time of between 2 and 4 h before the cells on the lower side of the pulvinus are committed to elongation. After 2 h of gravistimulation, the lower half consistently had higher IP3, and IP3 levels on the lower side continued to increase up to approximately 5-fold over basal levels before visible growth. As bending became visible after 8-10 h, IP3 levels returned to basal values. Additionally, phosphatidylinositol 4-phosphate 5-kinase activity in the lower pulvinus half increased transiently within 10 min of gravistimulation, suggesting that the increased IP3 production was accompanied by an up-regulation of phosphatidylinositol 4, 5-bisphosphate biosynthesis. Neither IP3 levels nor phosphatidylinositol 4-phosphate 5-kinase activity changed in pulvini halves from vertical control plants. Our data indicate the involvement of IP3 and inositol phospholipids in both short- and long-term responses to gravistimulation. As a diffusible second messenger, IP3 provides a mechanism to transmit and amplify the signal from the perceiving to the responding cells in the pulvinus, coordinating a synchronized growth response.

  15. Short-term treatment with cell wall degrading enzymes increases the activity of the inositol phospholipid kinases and the vanadate-sensitive ATPase of carrot cells.

    PubMed

    Chen, Q; Boss, W F

    1990-12-01

    Treating carrot (Daucus carota L.) suspension culture cells with a mixture of cell wall degrading enzymes, Driselase, resulted in an increase in the percentage of [(3)H]phosphatidylinositol bisphosphate. Analysis of the lipid kinase activities in the isolated plasma membranes after whole cell treatment indicated that treatment with Driselase (2% weight/volume; the equivalent of 340 units per milliliter of hemicellulase and 400 units per milliliter of cellulase activity) or treatment with hemicellulase (31.7% weight/volume, 20.7 units per milliliter) resulted in an increase in the inositol phospholipid kinase activity. However, treatment with cellulase alone had no effect at 0.5% (weight/volume, 17.2 units per milliliter) or inhibited the kinase activity at 1% (weight/volume, 34.4 units per milliliter). The active stimulus in Driselase was heat sensitive. The plasma membrane vanadate-sensitive ATPase activity also increased when the cells were treated with Driselase. A time course study indicated that both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase responded to as little as 5 seconds of treatment with 2% Driselase. However, at the lowest concentration of Driselase (0.04%, weight/volume) that resulted in an increase in inositol phospholipid kinase activity, the ATPase activity was not affected. Because inositol phospholipids have been shown to activate the vanadate-sensitive ATPase from plants (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301), a stimulus-response pathway involving both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase activity is discussed.

  16. Short-Term Treatment with Cell Wall Degrading Enzymes Increases the Activity of the Inositol Phospholipid Kinases and the Vanadate-Sensitive ATPase of Carrot Cells 1

    PubMed Central

    Chen, Qiuyun; Boss, Wendy F.

    1990-01-01

    Treating carrot (Daucus carota L.) suspension culture cells with a mixture of cell wall degrading enzymes, Driselase, resulted in an increase in the percentage of [3H]phosphatidylinositol bisphosphate. Analysis of the lipid kinase activities in the isolated plasma membranes after whole cell treatment indicated that treatment with Driselase (2% weight/volume; the equivalent of 340 units per milliliter of hemicellulase and 400 units per milliliter of cellulase activity) or treatment with hemicellulase (31.7% weight/volume, 20.7 units per milliliter) resulted in an increase in the inositol phospholipid kinase activity. However, treatment with cellulase alone had no effect at 0.5% (weight/volume, 17.2 units per milliliter) or inhibited the kinase activity at 1% (weight/volume, 34.4 units per milliliter). The active stimulus in Driselase was heat sensitive. The plasma membrane vanadate-sensitive ATPase activity also increased when the cells were treated with Driselase. A time course study indicated that both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase responded to as little as 5 seconds of treatment with 2% Driselase. However, at the lowest concentration of Driselase (0.04%, weight/volume) that resulted in an increase in inositol phospholipid kinase activity, the ATPase activity was not affected. Because inositol phospholipids have been shown to activate the vanadate-sensitive ATPase from plants (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301), a stimulus-response pathway involving both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase activity is discussed. Images Figure 2 Figure 6 PMID:16667922

  17. Effects of prostaglandin F2 alpha and a gonadotropin-releasing hormone agonist on inositol phospholipid metabolism in isolated rat corpora lutea of various ages

    SciTech Connect

    Lahav, M.; West, L.A.; Davis, J.S.

    1988-08-01

    The sensitivity of rat corpora lutea to luteolytic agents increases with luteal age. We examined the effect of prostaglandin F2 alpha (PGF2 alpha) and (D-Ala6,Des-Gly10)GnRH ethylamide (GnRHa) on inositol phospholipid metabolism in day 2 and day 7 corpora lutea from PMSG-treated rats. Isolated corpora lutea were incubated with 32PO4 or (3H)inositol and were treated with LH, PGF2 alpha, or GnRHa. Phospholipids were purified by TLC, and the water-soluble products of phospholipase-C activity (inositol phosphates) were isolated by ion exchange chromatography. In day 2 corpora lutea, PGF2 alpha, (10 microM) and GnRHa (100 ng/ml) significantly increased 32PO4 incorporation into phosphatidic acid (PA) and phosphatidylinositol (PI), but not into other fractions. LH provoked slight increases in PA. Results were similar with 30 min of prelabeling or simultaneous addition of 32PO4 and stimulants. In other experiments, PGF2 alpha and GnRHa provoked rapid increases (1-5 min) in the accumulation of inositol mono-, bis-, and trisphosphates. LH did not significantly increase inositol phosphate accumulation, but stimulated cAMP accumulation in 2-day-old corpora lutea. Inositol phospholipid metabolism was increased in day 7 corpora lutea compared to that in day 2 corpora lutea. This increase was associated with increased incorporation of 32PO4 into PA and PI and increased accumulation of (3H)inositol phosphates. In day 7 corpora lutea, which are very sensitive to the luteolytic effect of PGF2 alpha, the PG-induced increase in PA labeling was small and inconsistent, whereas PI labeling was unaffected in 30-min incubations. GnRHa was without effect in such corpora lutea. LH, PGF2 alpha, or GnRHa did not increase inositol phosphate accumulation in 7-day-old corpora lutea. These studies demonstrate that the transformation of young (day 2) to mature (day 7) corpora lutea is associated with an increase in luteal inositol phospholipid metabolism.

  18. Strategies for acquiring the phospholipid metabolite inositol in pathogenic bacteria, fungi and protozoa: making it and taking it

    PubMed Central

    Reynolds, Todd B.

    2009-01-01

    myo-Inositol (inositol) is an essential nutrient that is used for building phosphatidylinositol and its derivatives in eukaryotes and even in some eubacteria such as the mycobacteria. As a consequence, fungal, protozoan and mycobacterial pathogens must be able to acquire inositol in order to proliferate and cause infection in their hosts. There are two primary mechanisms for acquiring inositol. One is to synthesize inositol from glucose 6-phosphate using two sequentially acting enzymes: inositol-3-phosphate synthase (Ino1p) converts glucose 6-phosphate to inositol 3-phosphate, and then inositol monophosphatase (IMPase) dephosphorylates inositol 3-phosphate to generate inositol. The other mechanism is to import inositol from the environment via inositol transporters. Inositol is readily abundant in the bloodstream of mammalian hosts, providing a source from which many pathogens could potentially import inositol. However, despite this abundance of inositol in the host, some pathogens such as the bacterium Mycobacterium tuberculosis and the protist parasite Trypanosoma brucei must be able to make inositol de novo in order to cause disease (M. tuberculosis) or even grow (T. brucei). Other pathogens such as the fungus Candida albicans are equally adept at causing disease by importing inositol or by making it de novo. The role of inositol acquisition in the biology and pathogenesis of the parasite Leishmania and the fungus Cryptococcus are being explored as well. The specific strategies used by these pathogens to acquire inositol while in the host are discussed in relation to each pathogen's unique metabolic requirements. PMID:19383710

  19. Myo-inositol changes precede amyloid pathology and relate to APOE genotype in Alzheimer disease

    PubMed Central

    Sundgren, Pia C.; Strandberg, Olof; Zetterberg, Henrik; Minthon, Lennart; Blennow, Kaj; Wahlund, Lars-Olof; Westman, Eric

    2016-01-01

    Objective: We aimed to test whether in vivo levels of magnetic resonance spectroscopy (MRS) metabolites myo-inositol (mI), N-acetylaspartate (NAA), and choline are abnormal already during preclinical Alzheimer disease (AD), relating these changes to amyloid or tau pathology, and functional connectivity. Methods: In this cross-sectional multicenter study (a subset of the prospective Swedish BioFINDER study), we included 4 groups, representing the different stages of predementia AD: (1) cognitively healthy elderly with normal CSF β-amyloid 42 (Aβ42), (2) cognitively healthy elderly with abnormal CSF Aβ42, (3) patients with subjective cognitive decline and abnormal CSF Aβ42, (4) patients with mild cognitive decline and abnormal CSF Aβ42 (Ntotal = 352). Spectroscopic markers measured in the posterior cingulate/precuneus were considered alongside known disease biomarkers: CSF Aβ42, phosphorylated tau, total tau, [18F]-flutemetamol PET, f-MRI, and the genetic risk factor APOE. Results: Amyloid-positive cognitively healthy participants showed a significant increase in mI/creatine and mI/NAA levels compared to amyloid-negative healthy elderly (p < 0.05). In amyloid-positive healthy elderly, mI/creatine and mI/NAA correlated with cortical retention of [18F] flutemetamol tracer ( = 0.44, p = 0.02 and = 0.51, p = 0.01, respectively). Healthy elderly APOE ε4 carriers with normal CSF Aβ42 levels had significantly higher mI/creatine levels (p < 0.001) than ε4 noncarriers. Finally, elevated mI/creatine was associated with decreased functional connectivity within the default mode network (rpearson = −0.16, p = 0.02), independently of amyloid pathology. Conclusions: mI levels are elevated already at asymptomatic stages of AD. Moreover, mI/creatine concentrations were increased in healthy APOE ε4 carriers with normal CSF Aβ42 levels, suggesting that mI levels may reveal regional brain consequences of APOE ε4 before detectable amyloid pathology. PMID:27164711

  20. Endogenous TRPV1 stimulation leads to the activation of the inositol phospholipid pathway necessary for sustained Ca(2+) oscillations.

    PubMed

    Pecze, László; Blum, Walter; Henzi, Thomas; Schwaller, Beat

    2016-12-01

    Sensory neuron subpopulations as well as breast and prostate cancer cells express functional transient receptor potential vanilloid type 1 (TRPV1) ion channels; however little is known how TRPV1 activation leads to biological responses. Agonist-induced activation of TRPV1 resulted in specific spatiotemporal patterns of cytoplasmic Ca(2+) signals in breast and prostate cancer-derived cells. Capsaicin (CAPS; 50μM) evoked intracellular Ca(2+) oscillations and/or intercellular Ca(2+) waves in all cell lines. As evidenced in prostate cancer Du 145 cells, oscillations were largely dependent on the expression of functional TRPV1 channels in the plasma membrane, phospholipase C activation and on the presence of extracellular Ca(2+) ions. Concomitant oscillations of the mitochondrial matrix Ca(2+) concentration resulted in mitochondria energization evidenced by increased ATP production. CAPS-induced Ca(2+) oscillations also occurred in a subset of sensory neurons, yet already at lower CAPS concentrations (1μM). Stimulation of ectopically expressed TRPV1 channels in CAPS-insensitive NIH-3T3 cells didn't provoke CAPS-triggered Ca(2+) oscillations; rather it resulted in low-magnitude, long-lasting elevations of the cytosolic Ca(2+) concentration. This indicates that sole TRPV1 activation is not sufficient to generate Ca(2+) oscillations. Instead the initial TRPV1-mediated signal leads to the activation of the inositol phospholipid pathway. This in turn suffices to generate a biologically relevant frequency-modulated Ca(2+) signal.

  1. Coupling of inositol phospholipid hydrolysis to peptide hormone receptors expressed from adrenal and pituitary mRNA in Xenopus laevis oocytes

    SciTech Connect

    McIntosh, R.P.; Catt, K.J.

    1987-12-01

    The expression of several neurotransmitter and drug receptors from injected exogenous mRNA in Xenopus laevis oocytes has been demonstrated by electrophysiological measurements of ion channel activation. The expression of specific receptors for peptide hormones in such a translation system would facilitate studies on the structure and regulation of cell-surface receptors as well as their coupling to membrane transduction mechanisms. The expression of receptors for calcium-mobilizing hormones in Xenopus oocytes was sought by analysis of phospholipid turnover in hormone-stimulated oocytes. For this purpose, Xenopus oocytes were injected with mRNA extracted from bovine adrenal and pituitary glands and incubated with myo-(/sup 3/H)inositol to label plasma-membrane phosphatidylinositol phosphates. The expression of functionally active receptors for angiotensin II (AII) and thyrotropin-releasing hormone (TRH) was demonstrated by the stimulation of (/sup 3/H)inositol phosphate production by AII and TRH in the mRNA-injected, (/sup 3/H)inositol-prelabeled oocytes. The ability of AII and TRH to act by way of newly synthesized receptors from mammalian endocrine tissues to stimulate phosphatidylinositol polyphosphate hydrolysis in Xenopus oocytes suggests a generalized and conserved mechanism of receptor coupling to the transduction mechanism responsible for activation of phospholipase C in the plasma membrane.

  2. Influence of cyclic nucleotides (cAMP) on inositol phospholipid (InsPL) metabolism in cultured mesangial (MS) cells

    SciTech Connect

    Troyer, D.A.; Venkatachalam, M.A.; Bonventre, J.V.; Kreisberg, J.I.

    1986-03-01

    Elevation of cAMP inhibits hormone-induced contraction of MS cells, and in other cell types, reduces stimulated InsPL metabolism. The authors found that neither isobutylmethylxanthine (MIX, 0.5 mM), which increases MS cell cAMP levels 4-fold, nor forskolin (100 ..mu..M) altered vasopressin (VP, 10 nM) induced release of /sup 3/H-inositol trisphosphate from prelabelled MS cells. Also, maneuvers which elevated cAMP did not block the VP-induced rise of intracellular calcium as measured by quin-2. Further, neither MIX nor isoproterenol affected the stimulation of glycolysis by VP as measured by lactic acid production. MIX diminished VP stimulated /sup 32/P orthophosphate (/sup 32/P) incorporation into phosphatidylinositol 4,5-bisphosphate, phosphatidylinositol 4-phosphate and phosphatidylinositol. The /sup 32/P content in phosphoinositides of cells treated with MIX and VP was 65% of that in cells treated with VP only. However, the authors found that the specific activity of /sup 32/P in ATP in the presence of MIX + VP was 74% of that with VP alone. Thus, the apparent suppression of /sup 32/P incorporation due to MIX was attributable to a concurrent diminution of the specific activity of /sup 32/P in ATP. The authors conclude that increases of cAMP interfere with contraction distal to PIP/sub 2/ hydrolysis, inositol phosphate release, calcium mobilization, and enhancement of glycolysis.

  3. Changes in Band 3 oligomeric state precede cell membrane phospholipid loss during blood bank storage of red blood cells

    PubMed Central

    Karon, Brad S.; Hoyer, James D.; Stubbs, James R.; Thomas, David D.

    2013-01-01

    BACKGROUND Lipid loss in the form of vesicles contributes to the red blood cell (RBC) storage lesion, and this loss of lipid is correlated with changes in membrane protein function. Sensitive spectroscopic techniques were used to measure changes in Band 3 oligomeric state during storage of RBCs, compared to metabolic changes and phospholipid loss. The aim of the study was to determine whether changes in the macromolecular organization of membrane proteins occur before, coincident with, or after lipid loss during RBC storage. STUDY DESIGN AND METHODS Five RBC units were collected from normal volunteers and stored under standard blood bank conditions, and both metabolic changes and lipid loss were measured by multiple assays. Band 3 oligomeric state was assessed by time-resolved phosphorescence anisotropy and fluorescence resonance energy transfer of eosin-5-maleimide–labeled RBC ghosts. RESULTS Extracellular pH decreased and extracellular potassium increased rapidly during cold storage of blood. Band 3 on the RBC membrane exhibited a shift from small to large oligomers early in the storage period and before detectable loss of phospholipid from the RBC membrane. The immobilized fraction of Band 3, that which is tethered to the cytoskeletal network via spectrin and ankyrin, did not change during cold storage. CONCLUSION Our results demonstrate that changes in the macromolecular organization of membrane proteins on the RBC occur early in storage, and these changes may induce phospholipid loss, irreversible morphologic changes, and loss of function during RBC storage. PMID:19389033

  4. Antagonism by 8-hydroxy-2(di-n-propylamino)tetraline and other serotonin agonists of muscarinic M1-type receptors coupled to inositol phospholipid breakdown in human IMR-32 and SK-N-MC neuroblastoma cells

    SciTech Connect

    Fowler, C.J. Karolinska Institutet ); Ahlgren, P.C. ); O'Neill, C. )

    1991-01-01

    IMR-32 and SK-N-MC cells were found to contain ({sup 3}H)quinuclidinyl benzilate specific binding sites inhibited by pirenzepine in a manner suggesting the presence of both M1-type and M2-type muscarinic receptor recognition sites. Neither cell had detectable ({sup 3}H)8-OH-DPAT binding sites. Carbachol stimulated the rate of inositol phospholipid breakdown in IMR-32 and SK-N-MC human neuroblastoma cells with an EC{sub 50} value of about 50 {mu}M in both cases. Pirenzepine inhibited the carbachol stimulated inositol phospholipid breakdown in both cells with Hill slopes of unity and IC{sub 50} values of 15 nM (IMR-32) and 12 nM (SK-N-MC). The 5-HT{sub 1A} receptor agonist 8-OH-DPAT competitively inhibited carbachol-stimulated inositol phospholipid breakdown with pA{sub 2} values of 5.78 (IMR-32) and 5.61 (SK-N-MC). The 5-HT agonists 5-MeODMT and buspirone at micromolar concentrations inhibited carbachol-stimulated breakdown in IMR-32 cells. The inhibition by 8-OH-DPAT and 5-MeODMT was not affected by preincubation with (-)alprenolol. 5-HT was without effect on either basal or carbachol-stimulated breakdown. It is concluded that IMR-32 and SK-N-MC neuroblastoma cells express muscarinic M1-type but not serotoninergic receptors coupled to phosphoinositide-specific phospholipase C. 8-OH-DPAT acts as a weak antagonist at these muscarinic receptors.

  5. SAC1p is an integral membrane protein that influences the cellular requirement for phospholipid transfer protein function and inositol in yeast

    PubMed Central

    1993-01-01

    Mutations in the SAC1 gene exhibit allele-specific genetic interactions with yeast actin structural gene defects and effect a bypass of the cellular requirement for the yeast phosphatidylinositol/phosphatidylcholine transfer protein (SEC14p), a protein whose function is essential for sustained Golgi secretory function. We report that SAC1p is an integral membrane protein that localizes to the yeast Golgi complex and to the yeast ER, but does not exhibit a detectable association with the bulk of the yeast F-actin cytoskeleton. The data also indicate that the profound in vivo effects on Golgi secretory function and the organization of the actin cytoskeleton observed in sac1 mutants result from loss of SAC1p function. This cosuppression of actin and SEC14p defects is a unique feature of sac1 alleles as mutations in other SAC genes that result in a suppression of actin defects do not result in phenotypic suppression of SEC14p defects. Finally, we report that sac1 mutants also exhibit a specific inositol auxotrophy that is not exhibited by the other sac mutant strains. This sac1-associated inositol auxotrophy is not manifested by measurable defects in de novo inositol biosynthesis, nor is it the result of some obvious defect in the ability of sac1 mutants to utilize inositol for phosphatidylinositol biosynthesis. Thus, sac1 mutants represent a novel class of inositol auxotroph in that these mutants appear to require elevated levels of inositol for growth. On the basis of the collective data, we suggest that SAC1p dysfunction exerts its pleiotropic effects on yeast Golgi function, the organization of the actin cytoskeleton, and the cellular requirement for inositol, through altered metabolism of inositol glycerophospholipids. PMID:8314848

  6. Regulatory Mutations of Inositol Biosynthesis in Yeast: Isolation of Inositol-Excreting Mutants

    PubMed Central

    Greenberg, Miriam L.; Reiner, Barry; Henry, Susan A.

    1982-01-01

    The enzyme inositol-1-phosphate synthase (I-1-P synthase), product of the INO1 locus, catalyzes the synthesis of inositol-1-phosphate from the substrate glucose-6-phosphate. The activity of this enzyme is dramatically repressed in the presence of inositol. By selecting for mutants which overproduce and excrete inositol, we have identified mutants constitutive for inositol-1-phosphate synthase as well as a mutation in phospholipid biosynthesis. Genetic analysis of the mutants indicates that at least three loci (designated OPI1, OPI2 and OPI4) direct inositol-mediated repression of I-1-P synthase. Mutants of these loci synthesize I-1-P synthase constitutively. Three loci are unlinked to each other and to INO1, the structural gene for the enzyme. A mutant of a fourth locus, OPI3, does not synthesize I-1-P synthase constitutively, despite its inositol excretion phenotype. This mutant is preliminarily identified as having a defect in phospholipid synthesis. PMID:7047296

  7. Cell signalling and phospholipid metabolism

    SciTech Connect

    Boss, W.F.

    1990-01-01

    These studies explored whether phosphoinositide (PI) has a role in plants analogous to its role in animal cells. Although no parallel activity of PI in signal transduction was found in plant cells, activity of inositol phospholipid kinase was found to be modulated by light and by cell wall degrading enzymes. These studies indicate a major role for inositol phospholipids in plant growth and development as membrane effectors but not as a source of second messengers.

  8. Inositol phospholipids regulate the guanine-nucleotide-exchange factor Tiam1 by facilitating its binding to the plasma membrane and regulating GDP/GTP exchange on Rac1.

    PubMed

    Fleming, Ian N; Batty, Ian H; Prescott, Alan R; Gray, Alex; Kular, Gursant S; Stewart, Hazel; Downes, C Peter

    2004-09-15

    Binding of the Rac1-specific guanine-nucleotide-exchange factor, Tiam1, to the plasma membrane requires the N-terminal pleckstrin homology domain. In the present study, we show that membrane-association is mediated by binding of PtdIns(4,5)P(2) to the pleckstrin homology domain. Moreover, in 1321N1 astrocytoma cells, translocation of Tiam1 to the cytosol, following receptor-mediated stimulation of PtdIns(4,5)P(2) breakdown, correlates with decreased Rac1-GTP levels, indicating that membrane-association is required for GDP/GTP exchange on Rac1. In addition, we show that platelet-derived growth factor activates Rac1 in vivo by increasing PtdIns(3,4,5)P(3) concentrations, rather than the closely related lipid, PtdIns(3,4)P(2). Finally, the data demonstrate that PtdIns(4,5)P(2) and PtdIns(3,4,5)P(3) bind to the same pleckstrin homology domain in Tiam1 and that soluble inositol phosphates appear to compete with lipids for this binding. Together, these novel observations provide strong evidence that distinct phosphoinositides regulate different functions of this enzyme, indicating that local concentrations of signalling lipids and the levels of cytosolic inositol phosphates will play crucial roles in determining its activity in vivo.

  9. Inositol phospholipids regulate the guanine-nucleotide-exchange factor Tiam1 by facilitating its binding to the plasma membrane and regulating GDP/GTP exchange on Rac1

    PubMed Central

    2004-01-01

    Binding of the Rac1-specific guanine-nucleotide-exchange factor, Tiam1, to the plasma membrane requires the N-terminal pleckstrin homology domain. In the present study, we show that membrane-association is mediated by binding of PtdIns(4,5)P2 to the pleckstrin homology domain. Moreover, in 1321N1 astrocytoma cells, translocation of Tiam1 to the cytosol, following receptor-mediated stimulation of PtdIns(4,5)P2 breakdown, correlates with decreased Rac1-GTP levels, indicating that membrane-association is required for GDP/GTP exchange on Rac1. In addition, we show that platelet-derived growth factor activates Rac1 in vivo by increasing PtdIns(3,4,5)P3 concentrations, rather than the closely related lipid, PtdIns(3,4)P2. Finally, the data demonstrate that PtdIns(4,5)P2 and PtdIns(3,4,5)P3 bind to the same pleckstrin homology domain in Tiam1 and that soluble inositol phosphates appear to compete with lipids for this binding. Together, these novel observations provide strong evidence that distinct phosphoinositides regulate different functions of this enzyme, indicating that local concentrations of signalling lipids and the levels of cytosolic inositol phosphates will play crucial roles in determining its activity in vivo. PMID:15242348

  10. Cell signalling and phospholipid metabolism. Final report

    SciTech Connect

    Boss, W.F.

    1990-12-31

    These studies explored whether phosphoinositide (PI) has a role in plants analogous to its role in animal cells. Although no parallel activity of PI in signal transduction was found in plant cells, activity of inositol phospholipid kinase was found to be modulated by light and by cell wall degrading enzymes. These studies indicate a major role for inositol phospholipids in plant growth and development as membrane effectors but not as a source of second messengers.

  11. Cell signalling and phospholipid metabolism

    SciTech Connect

    Boss, W.F.

    1989-01-01

    Our research for the past two years has involved the study of phosphoinositides and their potential role in regulating plant growth and development. Our initial goal was to document the sequence of events involved in inositol phospholipid metabolism in response to external stimuli. Our working hypothesis was that phosphatidylinositol bisphosphate (PIP/sub 2/) was in the plasma membrane of plants cells and would be hydrolyzed by phospholipase C to yield the second messengers inositol triphosphate (IP/sub 3/) and diacyglycerol (DAG) and that IP/sub 3/ would mobilize intracellular calcium as has been shown for animal cells. Our results with both carrot suspension culture cells and sunflower hypocotyl indicate that this paradigm is not the primary mechanism of signal transduction in these systems. We have observed very rapid, within 5 sec, stimulation of phosphatidylinositol monophosphate (PIP) kinase which resulted in an increase in PIP/sub 2/. However, there was no evidence for activation of phospholipase C. In addition, we have shown that PIP and PIP/sub 2/ can activate the plasma membrane ATPase. The results of these studies are described briefly in the paragraphs below. Inositol phospholipids are localized in distinct membrane fractions. If PIP and PIP/sub 2/ play a role in the transduction of external signals, they should be present in the plasma membrane. We used the fusogenic carrot suspension culture cells as a model system to study the distribution of inositol phospholipids in various membrane fractions and organelles. Cells were labeled 12 to 18 h with myo(2-/sup 3/H) inositol and the membranes were isolated by aqueous two-phase partitioning. The plasma membrane was enriched in PIP and PIP/sub 2/ compared to the intracellular membranes.

  12. Phosphate, inositol and polyphosphates.

    PubMed

    Livermore, Thomas M; Azevedo, Cristina; Kolozsvari, Bernadett; Wilson, Miranda S C; Saiardi, Adolfo

    2016-02-01

    Eukaryotic cells have ubiquitously utilized the myo-inositol backbone to generate a diverse array of signalling molecules. This is achieved by arranging phosphate groups around the six-carbon inositol ring. There is virtually no biological process that does not take advantage of the uniquely variable architecture of phosphorylated inositol. In inositol biology, phosphates are able to form three distinct covalent bonds: phosphoester, phosphodiester and phosphoanhydride bonds, with each providing different properties. The phosphoester bond links phosphate groups to the inositol ring, the variable arrangement of which forms the basis of the signalling capacity of the inositol phosphates. Phosphate groups can also form the structural bridge between myo-inositol and diacylglycerol through the phosphodiester bond. The resulting lipid-bound inositol phosphates, or phosphoinositides, further expand the signalling potential of this family of molecules. Finally, inositol is also notable for its ability to host more phosphates than it has carbons. These unusual organic molecules are commonly referred to as the inositol pyrophosphates (PP-IPs), due to the presence of high-energy phosphoanhydride bonds (pyro- or diphospho-). PP-IPs themselves constitute a varied family of molecules with one or more pyrophosphate moiety/ies located around the inositol. Considering the relationship between phosphate and inositol, it is no surprise that members of the inositol phosphate family also regulate cellular phosphate homoeostasis. Notably, the PP-IPs play a fundamental role in controlling the metabolism of the ancient polymeric form of phosphate, inorganic polyphosphate (polyP). Here we explore the intimate links between phosphate, inositol phosphates and polyP, speculating on the evolution of these relationships. © 2016 Authors; published by Portland Press Limited.

  13. The response to inositol: regulation of glycerolipid metabolism and stress response signaling in yeast

    PubMed Central

    Henry, Susan A.; Gaspar, Maria L.; Jesch, Stephen A.

    2014-01-01

    This article focuses on discoveries of the mechanisms governing the regulation of glycerolipid metabolism and stress response signaling in response to the phospholipid precursor, inositol. The regulation of glycerolipid lipid metabolism in yeast in response to inositol is highly complex, but increasingly well understood, and the roles of individual lipids in stress response are also increasingly well characterized. Discoveries that have emerged over several decades of genetic, molecular and biochemical analyses of metabolic, regulatory and signaling responses of yeast cells, both mutant and wild type, to the availability of the phospholipid precursor, inositol are discussed. PMID:24418527

  14. Coordinate regulation of phospholipid biosynthesis in Saccharomyces cerevisiae: pleiotropically constitutive opi1 mutant.

    PubMed Central

    Klig, L S; Homann, M J; Carman, G M; Henry, S A

    1985-01-01

    Phospholipid metabolism in the Saccharomyces cerevisiae opi1 mutant, which excretes inositol and is constitutive for the biosynthetic enzyme inositol-1-phosphate synthase (M. Greenberg, P. Goldwasser, and S. Henry, Mol. Gen. Genet. 186:157-163, 1982), was examined and compared to that of a wild-type strain. In wild-type S. cerevisiae, the phospholipid composition and the relative rates of synthesis of individual phospholipids change in response to the availability of exogenous supplies of soluble phospholipid precursors, particularly inositol. The opi1 mutant, in contrast, displays a relatively invariant phospholipid composition, and its pattern of phospholipid synthesis does not change in response to exogenous phospholipid precursors. Phosphatidylinositol synthase was not found to be regulated in either wild-type or opi1 cells. In wild-type cells, phosphatidylserine synthase and the phospholipid N-methyltransferases are coordinately repressed in response to a combination of inositol and choline. However, in opi1 cells these activities are expressed constitutively. These results suggest that the gene product of the OPI1 locus participates in the coordinate regulation of phospholipid synthesis. Images PMID:3888957

  15. Chloride secretagogues stimulate inositol phosphate formation in shark rectal gland tubules cultured in suspension

    SciTech Connect

    Ecay, T.W.; Valentich, J.D. )

    1991-03-01

    Neuroendocrine activation of transepithelial chloride secretion by shark rectal gland cells is associated with increases in cellular cAMP, cGMP, and free calcium concentrations. We report here on the effects of several chloride secretagogues on inositol phosphate formation in cultured rectal gland tubules. Vasoactive intestinal peptide (VIP), atriopeptin (AP), and ionomycin increase the total inositol phosphate levels of cultured tubules, as measured by ion exchange chromatography. Forskolin, a potent chloride secretagogue, has no effect on inositol phosphate formation. The uptake of {sup 3}H-myo-inositol into phospholipids is very slow, preventing the detection of increased levels of inositol trisphosphate. However, significant increases in inositol monophosphate (IP1) and inositol biphosphate (IP2) were measured. The time course of VIP- and AP-stimulated IP1 and IP2 formation is similar to the effects of these agents on the short-circuit current responses of rectal gland monolayer cultures. In addition, aluminum fluoride, an artificial activator of guanine nucleotide-binding proteins, stimulates IP1 and IP2 formation. We conclude that rectal gland cells contain VIP and AP receptors coupled to the activation of phospholipase C. Coupling may be mediated by G-proteins. Receptor-stimulated increases in inositol phospholipid metabolism is one mechanism leading to increased intracellular free calcium concentrations, an important regulatory event in the activation of transepithelial chloride secretion by shark rectal gland epithelial cells.

  16. Trypanosoma brucei Bloodstream Forms Depend upon Uptake of myo-Inositol for Golgi Complex Phosphatidylinositol Synthesis and Normal Cell Growth.

    PubMed

    González-Salgado, Amaia; Steinmann, Michael; Major, Louise L; Sigel, Erwin; Reymond, Jean-Louis; Smith, Terry K; Bütikofer, Peter

    2015-06-01

    myo-Inositol is a building block for all inositol-containing phospholipids in eukaryotes. It can be synthesized de novo from glucose-6-phosphate in the cytosol and endoplasmic reticulum. Alternatively, it can be taken up from the environment via Na(+)- or H(+)-linked myo-inositol transporters. While Na(+)-coupled myo-inositol transporters are found exclusively in the plasma membrane, H(+)-linked myo-inositol transporters are detected in intracellular organelles. In Trypanosoma brucei, the causative agent of human African sleeping sickness, myo-inositol metabolism is compartmentalized. De novo-synthesized myo-inositol is used for glycosylphosphatidylinositol production in the endoplasmic reticulum, whereas the myo-inositol taken up from the environment is used for bulk phosphatidylinositol synthesis in the Golgi complex. We now provide evidence that the Golgi complex-localized T. brucei H(+)-linked myo-inositol transporter (TbHMIT) is essential in bloodstream-form T. brucei. Downregulation of TbHMIT expression by RNA interference blocked phosphatidylinositol production and inhibited growth of parasites in culture. Characterization of the transporter in a heterologous expression system demonstrated a remarkable selectivity of TbHMIT for myo-inositol. It tolerates only a single modification on the inositol ring, such as the removal of a hydroxyl group or the inversion of stereochemistry at a single hydroxyl group relative to myo-inositol. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Regulation of Phospholipid Synthesis in the Yeast Saccharomyces cerevisiae

    PubMed Central

    Carman, George M.; Han, Gil-Soo

    2013-01-01

    The yeast Saccharomyces cerevisiae, with its full complement of organelles, synthesizes membrane phospholipids by pathways that are generally common to those found in higher eukaryotes. Phospholipid synthesis in yeast is regulated in response to a variety of growth conditions (e.g., inositol supplementation, zinc depletion, and growth stage) by a coordination of genetic (e.g., transcriptional activation and repression) and biochemical (e.g., activity modulation and localization) mechanisms. Phosphatidate (PA), whose cellular levels are controlled by the activities of key phospholipid synthesis enzymes, plays a central role in the transcriptional regulation of phospholipid synthesis genes. In addition to the regulation of gene expression, phosphorylation of key phospholipid synthesis catalytic and regulatory proteins controls the metabolism of phospholipid precursors and products. PMID:21275641

  18. Regulation of phospholipid synthesis in the yeast Saccharomyces cerevisiae.

    PubMed

    Carman, George M; Han, Gil-Soo

    2011-01-01

    The yeast Saccharomyces cerevisiae, with its full complement of organelles, synthesizes membrane phospholipids by pathways that are generally common to those found in higher eukaryotes. Phospholipid synthesis in yeast is regulated in response to a variety of growth conditions (e.g., inositol supplementation, zinc depletion, and growth stage) by a coordination of genetic (e.g., transcriptional activation and repression) and biochemical (e.g., activity modulation and localization) mechanisms. Phosphatidate (PA), whose cellular levels are controlled by the activities of key phospholipid synthesis enzymes, plays a central role in the transcriptional regulation of phospholipid synthesis genes. In addition to the regulation of gene expression, phosphorylation of key phospholipid synthesis catalytic and regulatory proteins controls the metabolism of phospholipid precursors and products.

  19. Functional expression of a myo-inositol/H+ symporter from Leishmania donovani.

    PubMed Central

    Drew, M E; Langford, C K; Klamo, E M; Russell, D G; Kavanaugh, M P; Landfear, S M

    1995-01-01

    The vast majority of surface molecules in such kinetoplastid protozoa as members of the genus Leishmania contain inositol and are either glycosyl inositol phospholipids or glycoproteins that are tethered to the external surface of the plasma membrane by glycosylphosphatidylinositol anchors. We have shown that the biosynthetic precursor for these abundant glycolipids, myo-inositol, is translocated across the parasite plasma membrane by a specific transporter that is structurally related to mammalian facilitative glucose transporters. This myo-inositol transporter has been expressed and characterized in Xenopus laevis oocytes. Two-electrode voltage clamp experiments demonstrate that this protein is a sodium-independent electrogenic symporter that appears to utilize a proton gradient to concentrate myo-inositol within the cell. Immunolocalization experiments with a transporter-specific polyclonal antibody reveal the presence of this protein in the parasite plasma membrane. PMID:7565702

  20. Serotonergic agonists stimulate inositol lipid metabolism in rabbit platelets

    SciTech Connect

    Schaechter, M.; Godfrey, P.P.; Minchin, M.C.W.; McClue, S.J.; Young, M.M.

    1985-10-28

    The metabolism of inositol phospholipids in response to serotonergic agonists was investigated in rabbit platelets. In platelets prelabelled with (/sup 3/H)-inositol, in a medium containing 10 mM LiCl which blocks the enzyme inositol-1-phosphatase, 5-hydroxytryptamine (5-HT) caused a dose-dependent accumulation of inositol phosphates (IP). This suggests a phospholipase-C-mediated breakdown of phosphoinositides. Ketanserin, a selective 5-HT/sub 2/ antagonist, was a potent inhibitor of the 5-HT response, with a Ki of 28 nM, indicating that 5-HT is activating receptors of the 5-HT/sub 2/ type in the platelet. Lysergic acid diethylamide (LSD) and quipazine also caused dose-related increases in inositol phosphate levels, though these were considerably less than those produced by 5-HT. These results show that relatively small changes in phosphoinositide metabolism induced by serotonergic agonists can be investigated in the rabbit platelet, and this cell may therefore be a useful model for the study of some 5-HT receptors. 30 references, 4 figures.

  1. Noradrenaline stimulation of the phosphoinositide system: evidence for a novel hydrophobic inositol-containing compound in resistance arterioles.

    PubMed Central

    Ollerenshaw, J. D.; Heagerty, A. M.; Swales, J. D.

    1988-01-01

    1. Five inositol phosphates were extracted from adult rat resistance arterioles and separated by ion-exchange high performance liquid chromatography. 2. By use of this technique, inositol phosphates liberated were identified as inositol 1-phosphate, inositol 1,4-bisphosphate, inositol 1,3,4-trisphosphate, inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate. Stimulation of phosphoinositide hydrolysis with noradrenaline produced increases in inositol phosphate production. 3. Three inositol-containing phospholipids extracted from resistance arterioles were measured as their glycerol esters following deacylation, thereby permitting an analysis of both membrane and cytosolic components of the phosphoinositide signalling system. 4. A substantial agonist-sensitive pool of a previously undescribed inositol but not glycerol-containing lipid extract component was also identified in this tissue. 5. These experiments for the first time allow a precise description of phosphoinositide metabolism in resting and agonist-stimulated resistance arterioles and provide data on a novel compound possibly similar to that recently described in other tissues. PMID:2840158

  2. Regulation of phospholipid synthesis in phosphatidylserine synthase-deficient (chol) mutants of Saccharomyces cerevisiae.

    PubMed Central

    Letts, V A; Henry, S A

    1985-01-01

    chol mutants of Saccharomyces cerevisiae are deficient in the synthesis of the phospholipid phosphatidylserine owing to lowered activity of the membrane-associated enzyme phosphatidylserine synthase. chol mutants are auxotrophic for ethanolamine or choline and, in the absence of these supplements, cannot synthesize phosphatidylethanolamine or phosphatidylcholine (PC). We exploited these characteristics of the chol mutants to examine the regulation of phospholipid metabolism in S. cerevisiae. Macromolecular synthesis and phospholipid metabolism were examined in chol cells starved for ethanolamine. As expected, when chol mutants were starved for ethanolamine, the rates of synthesis of the phospholipids phosphatidylethanolamine and PC declined rapidly. Surprisingly, however, coupled to the decline in PC biosynthesis was a simultaneous decrease in the overall rate of phospholipid synthesis. In particular, the rate of synthesis of phosphatidylinositol decreased in parallel with the decline in PC biosynthesis. The results obtained suggest that the slowing of PC biosynthesis in ethanolamine-starved chol cells leads to a coordinated decrease in the synthesis of all phospholipids. However, under conditions of ethanolamine deprivation in chol cells, the cytoplasmic enzyme inositol-1-phosphate synthase could not be repressed by exogenous inositol, and the endogenous synthesis of the phospholipid precursor inositol appeared to be elevated. The implications of these findings with respect to the coordinated regulation of phospholipid synthesis are discussed. Images PMID:2991194

  3. Regulation of phosphatidylserine synthase from Saccharomyces cerevisiae by phospholipid precursors.

    PubMed Central

    Poole, M A; Homann, M J; Bae-Lee, M S; Carman, G M

    1986-01-01

    The addition of ethanolamine or choline to inositol-containing growth medium of Saccharomyces cerevisiae wild-type cells resulted in a reduction of membrane-associated phosphatidylserine synthase (CDPdiacylglycerol:L-serine O-phosphatidyltransferase, EC 2.7.8.8) activity in cell extracts. The reduction of activity did not occur when inositol was absent from the growth medium. Under the growth conditions where a reduction of enzyme activity occurred, there was a corresponding qualitative reduction of enzyme subunit as determined by immunoblotting with antiserum raised against purified phosphatidylserine synthase. Water-soluble phospholipid precursors did not effect purified phosphatidylserine synthase activity. Phosphatidylserine synthase (activity and enzyme subunit) was not regulated by the availability of water-soluble phospholipid precursors in S. cerevisiae VAL2C(YEp CHO1) and the opi1 mutant. VAL2C(YEp CHO1) is a plasmid-bearing strain that over produces phosphatidylserine synthase activity, and the opi1 mutant is an inositol biosynthesis regulatory mutant. The results of this study suggest that the regulation of phosphatidylserine synthase by the availability of phospholipid precursors occurs at the level of enzyme formation and not at the enzyme activity level. Furthermore, the regulation of phosphatidylserine synthase is coupled to inositol synthesis. Images PMID:3023284

  4. Platelet activating factor activity in the phospholipids of bovine spermatozoa

    SciTech Connect

    Parks, J.E.; Hough, S.; Elrod, C. )

    1990-11-01

    Platelet activating factor (PAF) has been detected in sperm from several mammalian species and can affect sperm motility and fertilization. Because bovine sperm contain a high percentage of ether-linked phospholipid precursors required for PAF synthesis, a study was undertaken to determine the PAF activity of bovine sperm phospholipids. Total lipids of washed, ejaculated bull sperm were extracted, and phospholipids were fractionated by thin-layer chromatography. Individual phospholipid fractions were assayed for PAF activity on the basis of (3H)serotonin release from equine platelets. PAF activity was detected in the PAF fraction (1.84 pmol/mumol total phospholipid) and in serine/inositol (PS/PI), choline (CP), and ethanolamine phosphoglyceride (EP) and cardiolipin (CA) fractions. Activity was highest in the CP fraction (8.05 pmol/mumol total phospholipid). Incomplete resolution of PAF and neutral lipids may have contributed to the activity in the PS/PI and CA fractions, respectively. Phospholipids from nonsperm sources did not stimulate serotonin release. Platelet activation by purified PAF and by sperm phospholipid fractions was inhibited by the receptor antagonist SRI 63-675. These results indicate that bovine sperm contain PAF and that other sperm phospholipids, especially CP and EP, which are high in glycerylether components, are capable of receptor-mediated platelet activation.

  5. Inositol phosphates in the environment.

    PubMed Central

    Turner, Benjamin L; Papházy, Michael J; Haygarth, Philip M; McKelvie, Ian D

    2002-01-01

    The inositol phosphates are a group of organic phosphorus compounds found widely in the natural environment, but that represent the greatest gap in our understanding of the global phosphorus cycle. They exist as inositols in various states of phosphorylation (bound to between one and six phosphate groups) and isomeric forms (e.g. myo, D-chiro, scyllo, neo), although myo-inositol hexakisphosphate is by far the most prevalent form in nature. In terrestrial environments, inositol phosphates are principally derived from plants and accumulate in soils to become the dominant class of organic phosphorus compounds. Inositol phosphates are also present in large amounts in aquatic environments, where they may contribute to eutrophication. Despite the prevalence of inositol phosphates in the environment, their cycling, mobility and bioavailability are poorly understood. This is largely related to analytical difficulties associated with the extraction, separation and detection of inositol phosphates in environmental samples. This review summarizes the current knowledge of inositol phosphates in the environment and the analytical techniques currently available for their detection in environmental samples. Recent advances in technology, such as the development of suitable chromatographic and capillary electrophoresis separation techniques, should help to elucidate some of the more pertinent questions regarding inositol phosphates in the natural environment. PMID:12028785

  6. An accelerated mass spectrometric method for measuring myo-inositol in phosphatidylinositol in rat brain

    NASA Astrophysics Data System (ADS)

    Deutsch, Joseph; Ma, Kaizung; Rapoport, Stanley I.

    2006-03-01

    A fast and efficient chemical ionization mass spectrometric (CI-GC-MS) method for measuring myo-inositol in phosphatidylinositol (PtdIns) in rat brain has been developed. Previously, quantitation of PtdIns involved the release of the myo-inositol by two enzymatic reactions using phospholipase C and alkaline phosphatase. The hydrolytic action of these enzymes was replaced by using commercially available 48% hydrofluoric acid (HF) at 80 °C for 30 min. The process can be carried out on the crude Folch extract of brain phospholipids without prior thin layer chromatography (TLC) purification, thereby significantly increasing the speed of analysis. For quantification, unlabeled myo-inositol, labeled myo- and neo-inositol (internal standard) were converted to acetate derivatives and analyzed by CI-GC-MS.

  7. Two inositol hexakisphosphate kinases drive inositol pyrophosphate synthesis in plants

    USDA-ARS?s Scientific Manuscript database

    Inositol pyrophosphates are novel cellular signaling molecules with newly discovered roles in energy sensing and metabolic control. Studies in eukaryotes have revealed that these compounds turn over rapidly, and thus only small amounts accumulate. Inositol pyrophosphates have not been the subject of...

  8. Dietary inositol hexakisphosphate, but not myo-inositol, clearly improves hypercholesterolemia in rats fed casein-type amino acid mixtures and 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane.

    PubMed

    Okazaki, Yukako; Katayama, Tetsuyuki

    2008-10-01

    We have previously shown that dietary inositol hexakisphosphate (IP6) and myo-inositol prevent fatty liver in rats fed a casein-based diet containing 1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane (DDT). This study was performed to examine the comparative effects of dietary equimolar amounts of sodium IP6 (1.02%) and myo-inositol (0.2%) on the development of DDT-induced fatty liver and hypercholesterolemia in rats fed 20% casein-type amino acid mixtures designed to exclude a possible myo-inositol contaminant in casein. Thirty-six male Wistar rats were divided into 6 groups of 6 rats each for: a control group, myo-inositol-supplemented group, IP6-supplemented group, DDT-treated group, DDT + myo-inositol-supplemented group, and a DDT + IP6-supplemented group. Dietary IP6 clearly suppressed the rises in serum concentrations of cholesterol and phospholipids because of DDT feeding, but myo-inositol had no significant influence on such elevations. Dietary IP6, but not myo-inositol, caused significant body weight gain with or without DDT intake. Supplemental IP6 and myo-inositol significantly increased hepatic-free myo-inositol regardless of DDT intake and prevented fatty liver in rats fed DDT. In conclusion, dietary IP6 and myo-inositol exert similar effects on DDT-induced fatty liver and myo-inositol status but distinct effects on DDT-induced hypercholesterolemia and growth rate in rats fed casein-type amino acid mixtures.

  9. Regulation of phospholipid synthesis in Saccharomyces cerevisiae by zinc depletion

    PubMed Central

    Carman, George M.; Han, Gil-Soo

    2007-01-01

    The synthesis of phospholipids in the yeast Saccharomyces cerevisiae is regulated by zinc, an essential mineral required for growth and metabolism. Cells depleted of zinc contain increased levels of phosphatidylinositol and decreased levels of phosphatidylethanolamine. In addition to the major phospholipids, the levels of the minor phospholipids phosphatidate and diacylglycerol pyrophosphate decrease in the vacuole membrane of zinc-depleted cells. Alterations in phosphatidylinositol and phosphatidylethanolamine can be ascribed to an increase in PIS1-encoded phosphatidylinositol synthase activity and to decreases in the activities of CDP-diacylglycerol pathway enzymes including the CHO1-encoded phosphatidylserine synthase, respectively. Alterations in the minor vacuole membrane phospholipids are due to the induction of the DPP1-encoded diacylglycerol pyrophosphate phosphatase. These changes in the activities of phospholipid biosynthetic enzymes result from differential regulation of gene expression at the level of transcription. Under zinc-deplete conditions, the positive transcription factor Zap1p stimulates the expression of the DPP1 and PIS1 genes through the cis-acting element UASZRE. In contrast, the negative regulatory protein Opi1p, which is involved in inositol-mediated regulation of phospholipid synthesis, represses the expression of the CHO1 gene through the cis-acting element UASINO. Regulation of phospholipid synthesis may provide an important mechanism by which cells cope with the stress of zinc depletion, given the roles that phospholipids play in the structure and function of cellular membranes. PMID:16807089

  10. Carbamoylcholine and gastrin induce inositol lipid turnover in canine gastric parietal cells

    SciTech Connect

    Chiba, T.; Fisher, S.K.; Park, J.; Seguin, E.B.; Agranoff, B.W.; Yamada, Tadataka )

    1988-07-01

    The potential role of inositol phospholipid turnover in mediating acid secretion was examined in a preparation enriched for isolated canine gastric parietal cells. The stimulatory effects of carbamoylcholine (carbachol) and gastrin on parietal cell uptake of ({sup 14}C)aminopyrine were linked to dose- and time-dependent selective reduction in cellular phosphatidylinositol content, although the specific fatty acid composition of the phosphoinositides was not altered. Analysis of ({sup 3}H)inositol phosphates accumulated in cells prelabeled with ({sup 3}H)inositol revealed an increase in labeled inositol trisphosphate by 5 min of incubation with either carbachol or gastrin. Furthermore, after preincubation of parietal cells in medium containing ({sup 32}P)orthophosphate, the two secretagogues elicited a time-dependent decrease in {sup 32}P labeling of phosphatidylinositol 4,5-bisphosphate and concomitant increase in labeling of phosphatidic acid. These data demonstrate that the acid secretagogue actions of carbachol and gastrin are correlated with turnover of cellular inositol phospholipids in a preparation consisting predominantly of parietal cells.

  11. Genome Wide Analysis Reveals Inositol, not Choline, as the Major Effector of Ino2p-Ino4p and Unfolded Protein Response Target Gene Expression in Yeast

    PubMed Central

    Jesch, Stephen A.; Zhao, Xin; Wells, Martin T.; Henry, Susan A.

    2005-01-01

    SUMMARY In the yeast Saccharomyces cerevisiae the transcription of many genes encoding enzymes of phospholipid biosynthesis are repressed in cells grown in the presence of the phospholipid precursors inositol and choline. A genome-wide approach using cDNA microarray technology was utilized to profile the changes in the expression of all genes in yeast that respond to the exogenous presence of inositol and choline. We report that the global response to inositol is completely distinct from the effect of choline. Whereas the effect of inositol on gene expression was primarily repressing, the effect of choline on gene expression was activating. Moreover, the combination inositol and choline increased the number of repressed genes compared to inositol alone and enhanced the repression levels of a subset of genes that responded to inositol. In all, 110 genes were repressed in the presence of inositol and choline. Two distinct sets of genes exhibited differential expression in response to inositol or the combination of inositol and choline in wild type cells. One set of genes contained the UASINO sequence and were bound by Ino2p and Ino4p. Many of these genes were also negatively regulated by OPI1, suggesting a common regulatory mechanism for Ino2p, Ino4p, and Opi1p. Another non-overlapping set of genes were coregulated by the unfolded protein response pathway, an ER-localized stress response pathway, but were not dependent on OPI1 and did not show further repression when choline was present together with inositol. These results suggest that inositol is the major effector of target gene expression, while choline plays a minor role. PMID:15611057

  12. Metabolic and structural evidence for the existence of a third species of polyphosphoinositide in cells: D-phosphatidyl-myo-inositol 3-phosphate.

    PubMed Central

    Stephens, L; Hawkins, P T; Downes, C P

    1989-01-01

    When human 1321 N1 astrocytoma cells were labelled to steady state with [3H]inositol and briefly with [32P]orthophosphate, a compound which contained both radiotracers and which co-migrated with phosphatidylinositol-myo-inositol 4-phosphate during t.l.c. could be extracted in acidic chloroform/methanol. Treatment with methylamine under conditions which lead to deacylation of conventional glycerophospholipids yielded a water-soluble moiety which was labelled with both radioisotopes and was eluted from an anion-exchange h.p.l.c. column with a retention time similar to, but distinct from, that of glycerophosphoinositol 4-phosphate. Experiments using sodium periodate and selective phosphatase enzymes to degrade this compound systematically generated a series of products which suggested the structure of the parent phospholipid was phosphatidyl-myo-inositol 3-phosphate (PtdIns3P). PtdIns3P is metabolically closely related to the pool(s) of inositol phospholipid(s) that serves as substrate(s) for an agonist-sensitive phosphoinositidase C, as the levels of PtdIns3P fell significantly when 1321 N1 cells were stimulated with carbachol. The relative rate of turnover of the inositol moiety of PtdIns3P is similar to that of both of the major polyphosphoinositides and significantly higher than that of total cellular phosphatidyl-myo-inositol. This suggests that all three polyphosphoinositides are synthesized from a common, rapidly metabolized, pool of phosphatidyl-myo-inositol. PMID:2541684

  13. Interconversion of inositol (1,4,5)-trisphosphate to inositol (1,3,4,5)-tetrakisphosphate and (1,3,4)-trisphosphate in permeabilized adrenal glomerulosa cells is calcium-sensitive and ATP-dependent

    SciTech Connect

    Rossier, M.F.; Dentand, I.A.; Lew, P.D.; Capponi, A.M.; Vallotton, M.B.

    1986-08-29

    The metabolism of (/sub 3/H)inositol (1,4,5)-trisphosphate was followed in permeabilized bovine adrenal glomerulosa cells. At low Ca++ concentration (pCa = 7.2), more than 90% of (/sub 3/H)inositol (1,4,5)-trisphosphate had disappeared within 2 min, while two other metabolites, (/sub 3/H)inositol (1,3,4)-trisphosphate and (/sub 3/H)inositol (1,3,4,5)-tetrakisphosphate appeared progressively. At higher Ca++ concentrations (pCa = 5.7 and 4.8), the formation of these two metabolites was markedly increased, but completely abolished if the medium was ATP-depleted. The peak levels for the generation of (/sub 3/H)inositol (1,3,4,5)-tetrakisphosphate (1 min) preceded those of (3H)inositol (1,3,4)-trisphosphate and were closely correlated. These results suggest that, in adrenal glomerulosa cells, the isomer inositol (1,3,4)-trisphosphate is generated from inositol (1,4,5)-trisphosphate via a calcium-sensitive and ATP-dependent phosphorylation/dephosphorylation pathway involving the formation of inositol (1,3,4,5)-tetrakisphosphate.

  14. Regulation of phospholipid synthesis in phosphatidylserine synthase-deficient (chol) mutants of Saccharomyces cerevisiae

    SciTech Connect

    Letts, V.A.; Henry, S.A.

    1985-08-01

    Saccharomyces cerevisiae mutants, chol, are deficient in the synthesis of the phospholipid phosphatidylserine owing to lowered activity of the membrane-associated enzyme phosphatidylserine synthase. These mutants are auxotrophic for ethanolamine or choline and, in the absence of these supplements, cannot synthesize phosphatidylethanolamine or phosphatidylcholine (PC). The authors exploited these characteristics of the chol mutants to examine the regulation of phospholipid metabolism in S. cerevisiae. Macromolecular synthesis and phospholipid metabolism were examined in chol cells starved for ethanolamine. Coupled to the decline in PC biosynthesis was a simultaneous decrease in the overall rate of phospholipid synthesis. In particular, the rate of synthesis of phosphatidylinositol decreased in parallel with the decline in PC biosynthesis. However, under conditions of ethanolamine deprivation in chol cells, the cytoplasmic enzyme inositol-1-phosphate synthase could not be repressed by exogenous inositol, and the endogenous synthesis of the phospholipid precursor inositol appeared to be elevated. The implications of these findings with respect to the coordinated regulation of phospholipid synthesis are discussed.

  15. Phospholipid turnover and ultrastructural correlates during spontaneous germinal vesicle breakdown of the bovine oocyte: Effects of a cyclic AMP phosphodiesterase inhibitor

    SciTech Connect

    Homa, S.T.; Webster, S.D.; Russell, R.K. )

    1991-08-01

    The turnover of (32P)orthophosphate in bovine oocyte phospholipids was studied during the early stages of spontaneous meiotic maturation, and during inhibition of this process by the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methyl-xanthine (IBMX). Radioactive lipids were separated by TLC and the meiotic stage was determined cytogenetically. Ultrastructure of the nuclear membrane was examined using transmission EM. During the commitment period to meiotic resumption, which precedes germinal vesicle breakdown (GVBD), small localized convolutions appeared in the intact nuclear membrane. This was accompanied by a decrease in (32P)phosphatidic acid (PA) and an increase in (32P)-phosphatidylcholine (PC). This was followed by extensive convolutions, and subsequent dissociation, of the nuclear membrane, concomitant with a tremendous surge in (32P)PC and (32P)phosphatidylethanolamine (PE). The cAMP-mediated maintenance of meiotic arrest involved retention of entire nuclear envelope integrity and total inhibition of the surge in (32P)PC and (32P)PE which accompanied GVBD. The increase in (32P)phosphatidylinositol (PI) associated with all stages of early meiotic resumption was unaffected by IBMX. Microinjection of heparin inhibited GVBD, and injection of inositol 1,4,5-trisphosphate (IP3) overrode IBMX-maintained meiotic arrest in almost 40% of the oocytes. The results suggest that there may be several functions for phospholipid turnover in the regulation of spontaneous meiotic resumption in the bovine oocyte. The first precedes the commitment period, and involves IP3 generation to serve as the primary signal for meiotic resumption. The second occurs concomitant with the commitment period, is unaffected by the level of intracellular cAMP, and is associated with the general turnover of phospholipid.

  16. Role of phospholipids in the actions of prolactin in the mammary gland

    SciTech Connect

    Etindi, R.O.N.

    1987-01-01

    These studies were designed to determine the role of phospholipid turnover in the mechanism of action of prolactin in mammary gland explants derived from 12-14 day pregnant mice. Prolactin stimulates phospholipid biosynthesis 12-16h after cultured mouse mammary tissues are exposed to it. Prolactin stimulates phospholipid biosynthesis at physiological concentrations and the response is maximal at all PRL concentrations above 25 ng/ml. p-Bromphenacyl bromide (BPB) at concentrations of 50 ..mu..M and above and quinacrine (50 ..mu..M) abolish the actions of prolactin on casein and lipid biosynthesis in cultured mouse mammary gland explants. In mouse mammary gland explants, binding of prolactin to its receptor leads to a phospholipase C type hydrolysis of inositol phospholipids, but this effect is transient and does not occur immediately after hormone exposure. Prolactin significantly stimulated the accumulation of (/sup 3/H)label in inositol monophosphate (IP/sub 1/), inositol bisphosphate (IP/sub 2/) and inositol trisphosphate (IP/sub 3/) 1-3 hours after addition of prolactin. Gossypol, a drug which has been shown to be an inhibitor of kinase C activity in mouse mammary tissues, is shown to abolish several of the actions of prolactin in cultured mouse mammary gland expalants.

  17. Phosphatidic acid stimulates inositol 1,4,5-trisphosphate production in adult cardiac myocytes.

    PubMed

    Kurz, T; Wolf, R A; Corr, P B

    1993-03-01

    The cellular content of phosphatidic acid can increase in response to several agonists either by phosphorylation of diacylglycerol after phospholipase C-catalyzed hydrolysis of phospholipids or directly through activation of phospholipase D. Although previous findings indicated that the generation of phosphatidic acid was exclusively a means of regulation of the cellular concentration of diacylglycerol, more recent studies have indicated that phosphatidic acid may also directly regulate several cellular functions. Accordingly, the present study was performed to assess whether phosphatidic acid could stimulate cardiac phospholipase C in intact adult rabbit ventricular myocytes. The mass of inositol 1,4,5-trisphosphate [Ins (1,4,5)P3] was determined by a specific and sensitive binding protein assay and by direct mass measurement using anion exchange chromatography for separation of selected inositol phosphates and gas chromatography and mass spectrometry for quantification of inositol monophosphate (IP1), inositol bisphosphate (IP2), inositol trisphosphate (IP3), and inositol tetrakisphosphate (IP4). Phosphatidic acid (10(-9)-10(-6) M) elicited a rapid concentration-dependent increase in Ins (1,4,5)P3 accumulation, with the peak fourfold to fivefold increase at 30 seconds of stimulation; the concentration required for 50% of maximal stimulation was 4.4 x 10(-8) M. The time course of individual inositol phosphates indicated a successive increase in the mass of IP3, IP4, IP2, and IP1 in response to stimulation with phosphatidic acid. The production of Ins (1,4,5)P3 in response to phosphatidic acid was not altered in the absence of extracellular calcium or in the presence of extracellular EGTA (10(-3) M). Thus, these findings indicate that phosphatidic acid is a potent activator of inositol phosphate production in adult ventricular myocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Phosphatidylinositol synthase and phosphatidylinositol/inositol exchange reactions in turkey erythrocyte membranes.

    PubMed Central

    McPhee, F; Lowe, G; Vaziri, C; Downes, C P

    1991-01-01

    Unlike human erythrocytes, those from avian species, such as turkeys and chicks, rapidly incorporate myo-[3H]inositol into membrane phospholipids. The mechanisms regulating [3H]Ins labelling of phosphatidylinositol have been investigated using turkey erythrocyte membranes. In the absence of added nucleotides, [3H]inositol incorporation appears to proceed via phosphatidylinositol/inositol exchange, with a Km for inositol of 0.01 mM. The reaction was dependent upon divalent cations, either Mg2+ or Mn2+, with the latter metal ion being the more effective. [3H]Inositol incorporation was accelerated by CMP, especially when the concentration of Ins was greater than the Km for the exchange reaction. CMP-dependent labelling of PtdIns had a Km for inositol of 0.3 mM and for CMP of 0.015 mM. Divalent cations were also required for this reaction: activity peaked at 0.5 mM-Mn2+ and declined at higher concentrations. At relatively high concentrations, Mg2+ was more effective than Mn2+, with peak activity being achieved above 10 mM. CMP-dependent incorporation of [3H]inositol appears to reflect an exchange reaction catalysed by PtdIns synthase. Definitive evidence for the occurrence of PtdIns synthase in turkey erythrocyte membranes was obtained by demonstrating the formation of [14C]CMP-phosphatidate from [14C]CMP. The radioactivity could be efficiently chased from [14C]CMP-phosphatidate in the presence of unlabelled inositol. The detection of PtdIns synthase activity in morphologically simple turkey erythrocytes should help to clarify the subcellular distribution of this important component of the phosphatidylinositol cycle. PMID:1850237

  19. The incorporation of myo-inositol into phosphatidylinositol derivatives is stimulated during hormone-induced meiotic maturation of amphibian oocytes

    SciTech Connect

    Carrasco, D.; Allende, C.C.; Allende, J.E. )

    1990-12-01

    The incorporation of myo-({sup 3}H)inositol into phosphatidylinositol and its phosphorylated derivatives was studied by microinjection of the radioactive precursor into Xenopus laevis oocytes. Induction of meiotic maturation of the oocytes by treatment with either progesterone one or insulin resulted in a significant increase in the incorporation of myo-({sup 3}H)inositol into the phospholipid fraction. This increase occurred 3-6 h after hormonal treatment, a time coincident with the start of the breakdown of the nuclear envelope, and requires protein synthesis. The effect of progesterone and insulin contrasts with the effect of acetylcholine, which acts through a muscarinic receptor causing the activation of phospholipase C, since the latter effector causes an increase in myo-({sup 3}H)inositol incorporation, which is more rapid and does not require protein synthesis. These results suggest that the meiotic maturation process is connected with changes in inositol metabolism in the amphibian oocyte.

  20. Gravimagnetic perturbations preceding earthquakes

    NASA Astrophysics Data System (ADS)

    Sobisevich, A. L.; Sobisevich, L. E.; Kanonidi, K. Kh.; Likhodeev, D. V.

    2017-08-01

    Geophysical processes preceding the seismic event in the region of Ryukyu Islands are analyzed on the basis of observatory data. Conditions for generation and structural features of the induced gravimagnetic disturbances are specified.

  1. PRECEDE for Wellness.

    ERIC Educational Resources Information Center

    Bonaguro, John A.

    1981-01-01

    The PRECEDE model was developed for health educators in an effort to improve programs and to influence health behaviors. The model consists of several diagnostic phases: (1) epidemiological; (2) social; (3) behavioral; (4) educational; (5) administrative; and (6) evaluation. (JN)

  2. Crystal Structures of Type-II Inositol Polyphosphate 5-Phosphatase INPP5B with Synthetic Inositol Polyphosphate Surrogates Reveal New Mechanistic Insights for the Inositol 5-Phosphatase Family

    PubMed Central

    2016-01-01

    The inositol polyphosphate 5-phosphatase INPP5B hydrolyzes the 5-phosphate group from water- and lipid-soluble signaling messengers. Two synthetic benzene and biphenyl polyphosphates (BzP/BiPhPs), simplified surrogates of inositol phosphates and phospholipid headgroups, were identified by thermodynamic studies as potent INPP5B ligands. The X-ray structure of the complex between INPP5B and biphenyl 3,3′,4,4′,5,5′-hexakisphosphate [BiPh(3,3′,4,4′,5,5′)P6, IC50 5.5 μM] was determined at 2.89 Å resolution. One inhibitor pole locates in the phospholipid headgroup binding site and the second solvent-exposed ring binds to the His-Tag of another INPP5B molecule, while a molecule of inorganic phosphate is also present in the active site. Benzene 1,2,3-trisphosphate [Bz(1,2,3)P3] [one ring of BiPh(3,3′,4,4′,5,5′)P6] inhibits INPP5B ca. 6-fold less potently. Co-crystallization with benzene 1,2,4,5-tetrakisphosphate [Bz(1,2,4,5)P4, IC50 = 6.3 μM] yielded a structure refined at 2.9 Å resolution. Conserved residues among the 5-phosphatase family mediate interactions with Bz(1,2,4,5)P4 and BiPh(3,3′,4,4′,5,5′)P6 similar to those with the polar groups present in positions 1, 4, 5, and 6 on the inositol ring of the substrate. 5-Phosphatase specificity most likely resides in the variable zone located close to the 2- and 3-positions of the inositol ring, offering insights to inhibitor design. We propose that the inorganic phosphate present in the INPP5B–BiPh(3,3′,4,4′,5,5′)P6 complex mimics the postcleavage substrate 5-phosphate released by INPP5B in the catalytic site, allowing elucidation of two new key features in the catalytic mechanism proposed for the family of phosphoinositide 5-phosphatases: first, the involvement of the conserved Arg-451 in the interaction with the 5-phosphate and second, identification of the water molecule that initiates 5-phosphate hydrolysis. Our model also has implications for the proposed “moving metal” mechanism

  3. Crystal Structures of Type-II Inositol Polyphosphate 5-Phosphatase INPP5B with Synthetic Inositol Polyphosphate Surrogates Reveal New Mechanistic Insights for the Inositol 5-Phosphatase Family.

    PubMed

    Mills, Stephen J; Silvander, Camilla; Cozier, Gyles; Trésaugues, Lionel; Nordlund, Pär; Potter, Barry V L

    2016-03-08

    The inositol polyphosphate 5-phosphatase INPP5B hydrolyzes the 5-phosphate group from water- and lipid-soluble signaling messengers. Two synthetic benzene and biphenyl polyphosphates (BzP/BiPhPs), simplified surrogates of inositol phosphates and phospholipid headgroups, were identified by thermodynamic studies as potent INPP5B ligands. The X-ray structure of the complex between INPP5B and biphenyl 3,3',4,4',5,5'-hexakisphosphate [BiPh(3,3',4,4',5,5')P6, IC50 5.5 μM] was determined at 2.89 Å resolution. One inhibitor pole locates in the phospholipid headgroup binding site and the second solvent-exposed ring binds to the His-Tag of another INPP5B molecule, while a molecule of inorganic phosphate is also present in the active site. Benzene 1,2,3-trisphosphate [Bz(1,2,3)P3] [one ring of BiPh(3,3',4,4',5,5')P6] inhibits INPP5B ca. 6-fold less potently. Co-crystallization with benzene 1,2,4,5-tetrakisphosphate [Bz(1,2,4,5)P4, IC50 = 6.3 μM] yielded a structure refined at 2.9 Å resolution. Conserved residues among the 5-phosphatase family mediate interactions with Bz(1,2,4,5)P4 and BiPh(3,3',4,4',5,5')P6 similar to those with the polar groups present in positions 1, 4, 5, and 6 on the inositol ring of the substrate. 5-Phosphatase specificity most likely resides in the variable zone located close to the 2- and 3-positions of the inositol ring, offering insights to inhibitor design. We propose that the inorganic phosphate present in the INPP5B-BiPh(3,3',4,4',5,5')P6 complex mimics the postcleavage substrate 5-phosphate released by INPP5B in the catalytic site, allowing elucidation of two new key features in the catalytic mechanism proposed for the family of phosphoinositide 5-phosphatases: first, the involvement of the conserved Arg-451 in the interaction with the 5-phosphate and second, identification of the water molecule that initiates 5-phosphate hydrolysis. Our model also has implications for the proposed "moving metal" mechanism.

  4. Inositol uptake in rat aorta

    SciTech Connect

    Rapoport, R.M.; Van Gorp, C.; Chang, Ki-Churl )

    1990-01-01

    {sup 3}H-inositol uptake into deendothelialized aorta was linear for at least 2 h and was composed of both a saturable, Na{sup +}-dependent, and a nonsaturable, Na{sup +}-independent component. The Na{sup +}-dependent component of inositol uptake had a K{sub m} of 50 {mu}M and a V{sub max} of 289 pmol/mg prot/h. Exposure to LiCl, ouabain, or Ca{sup 2+} - free Krebs-Ringer bicarbonate solution inhibited uptake. Metabolic poisoning with dinitrophenol, as well as incubation with phloretin, an inhibitor of carrier-mediated hexose transport, also inhibited uptake. Exposure to norepinephrine decreased inositol uptake, while phorbol myristate acetate was without effect. Isobutylmethylxanthine significantly increased inositol uptake, while the increased uptake due to dibutyryl cyclic AMP and forskolin were not statistically significant. Sodium nitroprusside, and activator of guanylate cyclase, and 8-bromo cyclic GMP, were without effect on uptake, as was methylene blue, an inhibitor of guanylate cyclase. Inositol uptake into the aorta was increased when the endothelium was allowed to remain intact, although this effect was likely due to uptake in both the endothelial and smooth muscle cells.

  5. NMR analyses of deuterated phospholipids isolated from Pichia angusta

    NASA Astrophysics Data System (ADS)

    Massou, S.; Augé, S.; Tropis, M.; Lindley, N. D.; Milon, A.

    1998-02-01

    The phospholipid composition of methylotrophic yeasts grown on deuterated and hydrogenated media has been determined by proton and phosphorus NMR. By using a line narrowing solvent, we could obtain linewidth lower than 2 Hz, and all the resonances could be resolved. Phospholipids were identified on the basis of their chemical shift and by 31P - H correlations (HMQC - HOHAHA gradient enhanced experiments). We have thus analysed qualitatively and quantitatively lipids mixtures directly after chloroform-methanol extraction. The lipid composition is deeply modified after growth in deuterated medium were phosphatidyl Inositol (PI) becomes the major lipid, instead of a PC, PS, PI mixture in hydrogenated conditions. La composition en phospholipides de levures méthylotrophes ayant poussé sur des milieux de cultures hydrogénés et deutériés a été déterminée par RMN du proton et du phosphore31. L'utilisation d'un solvant d'affinement a permis d'obtenir des largeurs de raies inférieures à 2Hz et de résoudre toutes les classes de phospholipides. Ils sont ensuite identifiés par leur déplacement chimique et par des corrélations phosphore - proton spécifiques (expériences HMQC-HOHAHA gradients). Cette approche a permis une analyse qualitative et quantitative de mélanges de phospholipides directement après extraction au chloroforme-méthanol. La composition en phospholipides est profondément modifiée lors de la croissance en milieu perdeutérié où l'on observe un lipide majoritaire, le phosphatidyl Inositol (PI), au lieu d'un mélange PC, PS PI en milieu hydrogéné.

  6. Regulation of phospholipid synthesis in Saccharomyces cerevisiae by zinc.

    PubMed

    Iwanyshyn, Wendy M; Han, Gil-Soo; Carman, George M

    2004-05-21

    Zinc is an essential nutrient required for the growth and metabolism of eukaryotic cells. In this work, we examined the effects of zinc depletion on the regulation of phospholipid synthesis in the yeast Saccharomyces cerevisiae. Zinc depletion resulted in a decrease in the activity levels of the CDP-diacylglycerol pathway enzymes phosphatidylserine synthase, phosphatidylserine decarboxylase, phosphatidylethanolamine methyltransferase, and phospholipid methyltransferase. In contrast, the activity of phosphatidylinositol synthase was elevated in response to zinc depletion. The level of Aut7p, a marker for the induction of autophagy, was also elevated in zinc-depleted cells. For the CHO1-encoded phosphatidylserine synthase, the reduction in activity in response to zinc depletion was controlled at the level of transcription. This regulation was mediated through the UAS(INO) element and by the transcription factors Ino2p, Ino4p, and Opi1p that are responsible for the inositol-mediated regulation of UAS(INO)-containing genes involved in phospholipid synthesis. Analysis of the cellular composition of the major membrane phospholipids showed that zinc depletion resulted in a 66% decrease in phosphatidylethanolamine and a 29% increase in phosphatidylinositol. A zrt1Delta zrt2Delta mutant (defective in the plasma membrane zinc transporters Zrt1p and Zrt2p) grown in the presence of zinc exhibited a phospholipid composition similar to that of wild type cells depleted for zinc. These results indicated that a decrease in the cytoplasmic levels of zinc was responsible for the alterations in phospholipid composition.

  7. Prevention of Prostate Cancer by Inositol Hexaphosphate

    DTIC Science & Technology

    2007-02-01

    signaling pathways therby inhibit growth. A large number of studies have pointed out that inositol hexaphosphate ( IP6 ) could have beneficial effect on...years, a large number of studies have pointed out that inositol hexaphosphate ( IP6 ), the most abundant phosphorylated inositol present in beans, cereal... inositol hexaphosphate ( IP6 ) on the growth and development of prostate cancer in TRAMP mice. To test the efficacy of IP6 in preventing prostate cancer

  8. Prevention of Prostate Cancer by Inositol Hexaphosphate

    DTIC Science & Technology

    2005-02-01

    studies have pointed out that inositol hexaphosphate ( IP6 ), the most abundant phosphorylated inositol present in beans, cereal grains, lentils and legumes...under the "Statement of Work", I proposed that my first task would be to determine the in vivo effects of inositol hexaphosphate ( IP6 ) on the growth and...AD Award Number: DAMDl7-03-1-0080 TITLE: Prevention of Prostate Cancer by Inositol Hexaphosphate PRINCIPAL INVESTIGATOR: Partha P. Banerjee, Ph.D

  9. Inositol, neural tube closure and the prevention of neural tube defects

    PubMed Central

    Leung, Kit‐Yi; Copp, Andrew J.

    2017-01-01

    Susceptibility to neural tube defects (NTDs), such as anencephaly and spina bifida is influenced by genetic and environmental factors including maternal nutrition. Maternal periconceptional supplementation with folic acid significantly reduces the risk of an NTD‐affected pregnancy, but does not prevent all NTDs, and “folic acid non‐responsive” NTDs continue to occur. Similarly, among mouse models of NTDs, some are responsive to folic acid but others are not. Among nutritional factors, inositol deficiency causes cranial NTDs in mice while supplemental inositol prevents spinal and cranial NTDs in the curly tail (Grhl3 hypomorph) mouse, rodent models of hyperglycemia or induced diabetes, and in a folate‐deficiency induced NTD model. NTDs also occur in mice lacking expression of certain inositol kinases. Inositol‐containing phospholipids (phosphoinositides) and soluble inositol phosphates mediate a range of functions, including intracellular signaling, interaction with cytoskeletal proteins, and regulation of membrane identity in trafficking and cell division. Myo‐inositol has been trialed in humans for a range of conditions and appears safe for use in human pregnancy. In pilot studies in Italy and the United Kingdom, women took inositol together with folic acid preconceptionally, after one or more previous NTD‐affected pregnancies. In nonrandomized cohorts and a randomized double‐blind study in the United Kingdom, no recurrent NTDs were observed among 52 pregnancies reported to date. Larger‐scale fully powered trials are needed to determine whether supplementation with inositol and folic acid would more effectively prevent NTDs than folic acid alone. Birth Defects Research 109:68–80, 2017. © 2016 The Authors Birth Defects Research Published by Wiley Periodicals, Inc. PMID:27324558

  10. Calcium-activated hydrolysis of phosphatidyl-myo-inositol 4-phosphate and phosphatidyl-myo-inositol 4,5-bisphosphate in guinea-pig synaptosomes

    PubMed Central

    Griffin, Harry D.; Hawthorne, John N.

    1978-01-01

    1. Addition of the bivalent ionophore A23187 to synaptosomes isolated from guinea-pig brain cortex and labelled with [32P]phosphate in vitro or in vivo caused a marked loss of radioactivity from phosphatidyl-myo-inositol 4-phosphate (diphosphoinositide) and phosphatidyl-myo-inositol 4,5-bisphosphate (triphosphoinositide) and stimulated labelling of phosphatidate. No change occurred in the labelling of other phospholipids. 2. In conditions that minimized changes in internal Mg2+ concentrations, the effect of ionophore A23187 on labelling of synaptosomal di- and tri-phosphoinositide was dependent on Ca2+ and was apparent at Ca2+ concentrations in the medium as low as 10−5m. 3. An increase in internal Mg2+ concentration stimulated incorporation of [32P]phosphate into di- and tri-phosphoinositide, whereas lowering internal Mg2+ decreased labelling. 4. Increased labelling of phosphatidate was independent of medium Mg2+ concentration and apparently only partly dependent on medium Ca2+ concentration. 5. The loss of label from di- and tri-phosphoinositide caused by ionophore A23187 was accompanied by losses in the amounts of both lipids. 6. Addition of excess of EGTA to synaptosomes treated with ionophore A23187 in the presence of Ca2+ caused a rapid resynthesis of di- and tri-phosphoinositide and a further stimulation of phosphatidate labelling. 7. Addition of ionophore A23187 to synaptosomes labelled in vivo with [3H]inositol caused a significant loss of label from di- and tri-phosphoinositide, but not from phosphatidylinositol. There was a considerable rise in labelling of inositol diphosphate, a small increase in that of inositol phosphate, but no significant production of inositol triphosphate. 8. 32P-labelled di- and tri-phosphoinositides appeared to be located in the synaptosomal plasma membrane. 9. The results indicate that increased Ca2+ influx into synaptosomes markedly activates triphosphoinositide phosphatase and diphosphoinositide phosphodiesterase, but has

  11. Rapid Degradation and Limited Synthesis of Phospholipids in the Cotyledons of Mung Bean Seedlings 1

    PubMed Central

    Gilkes, Neil R.; Herman, Eliot M.; Chrispeels, Maarten J.

    1979-01-01

    Seedling growth of mung bean is accompanied by the rapid catabolism of the three major phospholipids in the cotyledons (phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol). The decline starts 24 hours after the beginning of imbibition and by the 4th day of growth more than 50% of the phospholipids have been catabolized. Extracts of cotyledons of 24-hour-imbibed beans contain enzymes capable of degrading membrane-associated phospholipids in vitro. This degradation involves phospholipase D and phosphatase activity. Studies with radioactive acetate, glycerol, and orthophosphate indicate that the three major phospholipids are also synthesized in the cotyledons. Incorporation of glycerol and acetate into phospholipids of cotyledons is relatively constant throughout seedling growth, while the incorporation of [32P]orthophosphate steadily declines from a high value 24 hours after the start of imbibition. The newly synthesized phospholipids become associated with membranous organelles, especially the endoplasmic reticulum, and have an in situ half-life of 2 to 2.5 days. Determination of the activities of two enzymes involved in phospholipid biosynthesis (phosphorylcholine-glyceride transferase and CDP-diglyceride-inositol transferase) shows that the enzymes have their highest activities 12 hours after the start of imbibition. High activities for both enzymes were found in cotyledons of beans incubated at 1 C, indicating that the enzymes may preexist in the dry seeds. The experiments demonstrate that cotyledons start synthesizing new phospholipids immediately after imbibition, but that the rate of phospholipid catabolism far exceeds the rate of synthesis long before the cotyledons start to senesce. PMID:16660911

  12. Phospholipid metabolism and protein kinase C mediated protein phosphorylation in dietary protein deficiency in rat lung.

    PubMed

    Bansal, Surendra K; Kathayat, Rachna; Tyagi, Manoj; Taneja, Krishna K; Basir, Seemi F

    2005-07-01

    Nutritional deprivation of proteins decreases the protein kinase C (PKC) activity in rat lung. The activity of (PKC) is influenced by lipid metabolism. Changes in PKC activity may influence phosphorylation of its substrate proteins in the tissues. Therefore, alterations in phospholipid metabolism and PKC mediated protein phosphorylation in dietary protein deficiency in rat lung were envisaged. The study was conducted on rats fed on three different types of diet viz., casein (20% protein), deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threoning). Feeding of protein deficient diet caused reduction in incorporation of [3H] myo-inositol in the total phosphoinositides in lungs and an increase in total inositol phosphate pool. There was a significant reduction in the contents and turnover rate of phosphatidyl inositol and phosphatidyl inositol monophosphate. Supplementation of diet with L-lysine and DL-threonine had a reversing effect on total pool of phosphoinositides and, the metabolism of phosphatidyl inositol bisphosphate and phosphatidyl inositol. In phosphatidyl choline metabolism, the dietary protein deficiency led to a decrease in incorporation of [14C-methyl] choline-chloride in total phospholipids. In contrast, its incorporation increased in phosphatidyl choline pool. The contents of phosphatidyl choline and residue, incorporation of [14C-methyl] choline-chloride in them and their turnover rate also increased. Supplementation of diet had a reversal effect on most of these parameters. Phosphorylation of proteins of 84, 47, 35 and 16 kDa was identified to be mediated by PKC. In dietary protein deficiency, phosphorylation of all these proteins, except that of 47 kDa, increased. Supplementation of diet reversed the pattern except that of 84 kDa. The findings suggest that changes in phospholipid metabolism in dietary protein deficiency may effect the activity of PKC thereby influencing the

  13. Broad Spectrum Anticancer Activity of Myo-Inositol and Inositol Hexakisphosphate

    PubMed Central

    Dinicola, Simona

    2016-01-01

    Inositols (myo-inositol and inositol hexakisphosphate) exert a wide range of critical activities in both physiological and pathological settings. Deregulated inositol metabolism has been recorded in a number of diseases, including cancer, where inositol modulates different critical pathways. Inositols inhibit pRB phosphorylation, fostering the pRB/E2F complexes formation and blocking progression along the cell cycle. Inositols reduce PI3K levels, thus counteracting the activation of the PKC/RAS/ERK pathway downstream of PI3K activation. Upstream of that pathway, inositols disrupt the ligand interaction between FGF and its receptor as well as with the EGF-transduction processes involving IGF-II receptor and AP-1 complexes. Additionally, Akt activation is severely impaired upon inositol addition. Downregulation of both Akt and ERK leads consequently to NF-kB inhibition and reduced expression of inflammatory markers (COX-2 and PGE2). Remarkably, inositol-induced downregulation of presenilin-1 interferes with the epithelial-mesenchymal transition and reduces Wnt-activation, β-catenin translocation, Notch-1, N-cadherin, and SNAI1 release. Inositols interfere also with the cytoskeleton by upregulating Focal Adhesion Kinase and E-cadherin and decreasing Fascin and Cofilin, two main components of pseudopodia, leading hence to invasiveness impairment. This effect is reinforced by the inositol-induced inhibition on metalloproteinases and ROCK1/2 release. Overall, these effects enable inositols to remodel the cytoskeleton architecture. PMID:27795708

  14. CYTOTOXIC PHOSPHOLIPID OXIDATION PRODUCTS

    PubMed Central

    Chen, Rui; Yang, Lili; McIntyre, Thomas M.

    2008-01-01

    Phospholipid oxidation products accumulate in the necrotic core of atherosclerotic lesions, in apoptotic cells, and circulate in oxidized LDL. Phospholipid oxidation generates toxic products, but little is known about which specific products are cytotoxic, their receptors, or the mechanism(s) that induces cell death. We find the most common phospholipid oxidation product of oxidized LDL, phosphatidylcholine with esterified sn-2 azelaic acid, induced apoptosis at low micromolar concentrations. The synthetic ether phospholipid hexadecyl azelaoyl phosphatidylcholine (HAzPC) was rapidly internalized, and over-expression of PLA2g7 (PAF acetylhydrolase) that specifically hydrolyzes such oxidized phospholipids suppressed apoptosis. Internalized HAzPC associated with mitochondria, and cytochrome C and apoptosis-inducing factor escaped from mitochondria to the cytoplasm and nucleus, respectively, in cells exposed to HAzPC. Isolated mitochondria exposed to HAzPC rapidly swelled, and released cytochrome C and apoptosis-inducing factor. Other phospholipid oxidation products induced swelling, but HAzPC was the most effective and was twice as effective as its diacyl homolog. Cytoplasmic cytochrome C completes the apoptosome, and activated caspase 9 and 3 were present in cells exposed to HAzPC. Irreversible inhibition of caspase 9 blocked downstream caspase 3 activation, and prevented apoptosis. Mitochondrial damage initiated this apoptotic cascade because over-expression of Bcl-XL, an anti-apoptotic protein localized to mitochondria, blocked cytochrome C escape, and apoptosis. Thus, exogenous phospholipid oxidation products target intracellular mitochondria to activate the intrinsic apoptotic cascade. PMID:17597068

  15. Measurement of Inositol Triphosphate Levels from Rat Hippocampal Slices

    PubMed Central

    Tabatadze, Nino; Woolley, Catherine

    2016-01-01

    Inositol triphosphate (IP3) is an important second messenger that participates in signal transduction pathways in diverse cell types including hippocampal neurons. Stimulation of phospholipase C in response to various stimuli (hormones, growth factors, neurotransmitters, neurotrophins, neuromodulators, odorants, light, etc) results in hydrolysis of phosphatidylinositol 4, 5-bisphosphate (PIP2), a phospholipid that is located in the plasma membrane, and leads to the production of IP3 and diacylglycerol. Binding of IP3 to the IP3 receptor (IP3R) induces Ca2+ release from intracellular stores and enables the initiation of intracellular Ca2+-dependent signaling. Here we describe a procedure for the measurement of cellular IP3 levels in tissue homogenates prepared from rat hippocampal slices. PMID:27468425

  16. Phospholipids of Azotobacter vinelandii

    PubMed Central

    Jurtshuk, Peter; Schlech, Barry A.

    1969-01-01

    Analyses of resting cells of Azotobacter vinelandii revealed that numerous phospholipids were present that did not concentrate in the membranous R3 fraction which carried out electron transport function. PMID:5776538

  17. Synthesis of inositol phosphate ligands of plant hormone-receptor complexes: pathways of inositol hexakisphosphate turnover.

    PubMed

    Hanke, David E; Parmar, Paroo N; Caddick, Samuel E K; Green, Porntip; Brearley, Charles A

    2012-06-15

    Reduction of phytate is a major goal of plant breeding programs to improve the nutritional quality of crops. Remarkably, except for the storage organs of crops such as barley, maize and soybean, we know little of the stereoisomeric composition of inositol phosphates in plant tissues. To investigate the metabolic origins of higher inositol phosphates in photosynthetic tissues, we have radiolabelled leaf tissue of Solanum tuberosum with myo-[2-3H]inositol, undertaken a detailed analysis of inositol phosphate stereoisomerism and permeabilized mesophyll protoplasts in media containing inositol phosphates. We describe the inositol phosphate composition of leaf tissue and identify pathways of inositol phosphate metabolism that we reveal to be common to other kingdoms. Our results identify the metabolic origins of a number of higher inositol phosphates including ones that are precursors of cofactors, or cofactors of plant hormone-receptor complexes. The present study affords alternative explanations of the effects of disruption of inositol phosphate metabolism reported in other species, and identifies different inositol phosphates from that described in photosynthetic tissue of the monocot Spirodela polyrhiza. We define the pathways of inositol hexakisphosphate turnover and shed light on the occurrence of a number of inositol phosphates identified in animals, for which metabolic origins have not been defined.

  18. The inositols and polycystic ovary syndrome

    PubMed Central

    Kalra, Bharti; Kalra, Sanjay; Sharma, J. B.

    2016-01-01

    This review describes the rationale, biochemical, and clinical data related to the use of inositols in polycystic ovary syndrome (PCOS). It covers studies related to the mechanism of action of myo-inositol and D-chiro-inositol (MDI), with randomized controlled trials conducted in women with PCOS, and utilizes these data to suggest pragmatic indications and methods for using MDI combination in PCOS. Rationally crafted inositol combinations have a potential role to play in maintaining metabolic, endocrine, and reproductive health in women with PCOS. PMID:27730087

  19. Phospholipids from Bacillus stearothermophilus

    PubMed Central

    Card, George L.; Georgi, Carl E.; Militzer, Walter E.

    1969-01-01

    The lipids of Bacillus stearothermophilus strain 2184 were extracted with chloroform-methanol and separated into neutral lipid and three phospholipid fractions by chromatography on silicic acid columns. The phospholipids were identified by specific staining reactions on silicic acid-impregnated paper, by chromatography of alkaline and acid hydrolysis products, and by determination of acyl ester:glycerol:nitrogen:phosphorus molar ratios. The total extractable lipid was 8% of the dry weight of whole cells and consisted of 30 to 40% neutral lipid and 60 to 70% phospholipid. The phospholipid consisted of diphosphatidyl glycerol (23 to 42%), phosphatidyl glycerol (22 to 39%), and phosphatidyl ethanolamine (21 to 32%). The concentrations of diphosphatidyl glycerol and phosphatidyl glycerol were lower in 2-hr cells than in 4- and 8-hr cells. Whole cells were fractionated by sonic treatment and differential centrifugation. The total lipid content, expressed in per cent of dry weight of each fraction was: whole protoplasts, 10%; membrane fraction, 18%; 30,000 × g particulate fraction, 22%; and 105,000 × g particulate fraction, 26%. The relative phospholipid concentrations in each fraction were about the same. As had been previously reported, none of the phospholipid was stable to alkaline hydrolysis. Images PMID:5764328

  20. Flagellar membranes are rich in raft-forming phospholipids

    PubMed Central

    Serricchio, Mauro; Schmid, Adrien W.; Steinmann, Michael E.; Sigel, Erwin; Rauch, Monika; Julkowska, Daria; Bonnefoy, Serge; Fort, Cécile; Bastin, Philippe; Bütikofer, Peter

    2015-01-01

    ABSTRACT The observation that the membranes of flagella are enriched in sterols and sphingolipids has led to the hypothesis that flagella might be enriched in raft-forming lipids. However, a detailed lipidomic analysis of flagellar membranes is not available. Novel protocols to detach and isolate intact flagella from Trypanosoma brucei procyclic forms in combination with reverse-phase liquid chromatography high-resolution tandem mass spectrometry allowed us to determine the phospholipid composition of flagellar membranes relative to whole cells. Our analyses revealed that phosphatidylethanolamine, phosphatidylserine, ceramide and the sphingolipids inositol phosphorylceramide and sphingomyelin are enriched in flagella relative to whole cells. In contrast, phosphatidylcholine and phosphatidylinositol are strongly depleted in flagella. Within individual glycerophospholipid classes, we observed a preference for ether-type over diacyl-type molecular species in membranes of flagella. Our study provides direct evidence for a preferential presence of raft-forming phospholipids in flagellar membranes of T. brucei. PMID:26276100

  1. Inositol trisphosphate and calcium signalling

    NASA Astrophysics Data System (ADS)

    Berridge, Michael J.

    1993-01-01

    Inositol trisphosphate is a second messenger that controls many cellular processes by generating internal calcium signals. It operates through receptors whose molecular and physiological properties closely resemble the calcium-mobilizing ryanodine receptors of muscle. This family of intracellular calcium channels displays the regenerative process of calcium-induced calcium release responsible for the complex spatiotemporal patterns of calcium waves and oscillations. Such a dynamic signalling pathway controls many cellular processes, including fertilization, cell growth, transformation, secretion, smooth muscle contraction, sensory perception and neuronal signalling.

  2. Phosphatidate phosphatase regulates membrane phospholipid synthesis via phosphatidylserine synthase.

    PubMed

    Carman, George M; Han, Gil-Soo

    2017-08-16

    The yeast Saccharomyces cerevisiae serves as a model eukaryote to elucidate the regulation of lipid metabolism. In exponentially growing yeast, a diverse set of membrane lipids are synthesized from the precursor phosphatidate via the liponucleotide intermediate CDP-diacylglycerol. As cells exhaust nutrients and progress into the stationary phase, phosphatidate is channeled via diacylglycerol to the synthesis of triacylglycerol. The CHO1-encoded phosphatidylserine synthase, which catalyzes the committed step in membrane phospholipid synthesis via CDP-diacylglycerol, and the PAH1-encoded phosphatidate phosphatase, which catalyzes the committed step in triacylglycerol synthesis are regulated throughout cell growth by genetic and biochemical mechanisms to control the balanced synthesis of membrane phospholipids and triacylglycerol. The loss of phosphatidate phosphatase activity (e.g., pah1Δ mutation) increases the level of phosphatidate and its conversion to membrane phospholipids by inducing Cho1 expression and phosphatidylserine synthase activity. The regulation of the CHO1 expression is mediated through the inositol-sensitive upstream activation sequence (UASINO), a cis-acting element for the phosphatidate-controlled Henry (Ino2-Ino4/Opi1) regulatory circuit. Consequently, phosphatidate phosphatase activity regulates phospholipid synthesis through the transcriptional regulation of the phosphatidylserine synthase enzyme. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Inositol phosphates induce DAPI fluorescence shift.

    PubMed

    Kolozsvari, Bernadett; Parisi, Federica; Saiardi, Adolfo

    2014-06-15

    The polymer inorganic polyP (polyphosphate) and inositol phosphates, such as IP6 (inositol hexakisphosphate; also known as phytic acid), share many biophysical features. These similarities must be attributed to the phosphate groups present in these molecules. Given the ability of polyP to modify the excitation-emission spectra of DAPI we decided to investigate whether inositol phosphates possess the same property. We discovered that DAPI-IP6 complexes emit at approximately 550 nm when excited with light of wavelength 410-420 nm. IP5 (inositol pentakisphosphate) is also able to induce a similar shift in DAPI fluorescence. Conversely, IP3 (inositol trisphosphate) and IP4 (inositol tetrakisphosphate) are unable to shift DAPI fluorescence. We have employed this newly discovered feature of DAPI to study the enzymatic activity of the inositol polyphosphate multikinase and to monitor phytase phosphatase reactions. Finally, we used DAPI-IP6 fluorescence to determine the amount of IP6 in plant seeds. Using an IP6 standard curve this straight-forward analysis revealed that among the samples tested, borlotti beans possess the highest level of IP6 (9.4 mg/g of dry mass), whereas the Indian urad bean the lowest (3.2 mg/g of dry mass). The newly identified fluorescence properties of the DAPI-IP5 and DAPI-IP6 complexes allow the levels and enzymatic conversion of these two important messengers to be rapidly and reliably monitored.

  4. Importance and regulation of inositol biosynthesis during growth and differentiation of Streptomyces.

    PubMed

    Zhang, Guohua; Tian, Yuqing; Hu, Kun; Zhu, Yu; Chater, Keith F; Feng, Chi; Liu, Gang; Tan, Huarong

    2012-03-01

    Unusually among bacteria, actinobacteria possess myo-inositol 1-phosphate synthase (mIPS). In the developmentally complex Streptomyces coelicolor, the mIPS-encoding gene (inoA) is cotranscribed with a putative regulatory gene (inoR). The inoRA transcript was more abundant in an inoR in-frame deletion mutant, and InoR formed different complexes in vitro with an extensive region around the inoRA promoter. Binding was relieved by adding glucose 6-phosphate. Thus, InoR is a metabolite-sensitive autorepressor that influences inoA expression, and hence the level of inositol, by controlling transcription from P(inoRA) . Disruption of inoA resulted in inositol-dependent growth and development, with full phenotypic correction at 0.1 mM inositol: at lower inositol concentrations differentiation was arrested at intermediate stages. This pattern may partly reflect increased demand for membrane phospholipids during sporulation septation. A corresponding sharp upregulation of inoRA transcription coincident with sporulation was dependent on a developmental regulator, WhiI. A truncated form of WhiI could bind two sites downstream of P(inoRA) , and one of the WhiI-binding sites overlapped the InoR-binding site. The combined action of a metabolic regulator and a developmental regulator at the simple P(inoRA) promoter is a previously undescribed strategy for the differential provision of developmentally appropriate levels of a substance required during the formation of spore chains.

  5. Obstructed Diffusion of Phospholipids in Polymer-Tethered Phospholipid Bilayers

    NASA Astrophysics Data System (ADS)

    Deverall, Miranda; Ke, Puchun; Saxton, Michael; Naumann, Christoph

    2002-03-01

    The obstructed diffusion of phospholipids in polymer-tethered phospholipid bilayers is studied via single molecule fluorescence imaging. Here phospholipids tethered to the polymer cushion act as obstacles for the lateral diffusion of non-tethered phospholipids. The relationship between averaged mean-square displacement and time suggests a random distribution of obstacles at low and moderate obstacle molar concentrations and a micro-phase separation at high obstacle molar concentrations of >30 molcomparison to Monte Carlo calculations indicates that tethered phospholipids behave like mobile point obstacles, thereby showing similar diffusion properties to non-tethered phospholipids. Since polymer-lipid tethering is achieved via lipopolymer molecules consisting of polymer and lipid moieties with a significant molecular area mismatch between both moieties, our studies could help understand the effect that molecules of similar molecular geometries have on lipid diffusion in plasma membranes. In addition, our data are necessary for the understanding of the diffusion of incorporated proteins in phospholipid bilayers.

  6. Effects of inositol phosphates on mineral utilization

    SciTech Connect

    Tao, S.H.; Fox, M.R.S.; Phillippy, B.Q.; Fry, B.E. Jr.; Johnson, M.L.; Johnston, M.R.

    1986-03-05

    The present study was designed to compare the effects of inositol tri-, tetra-, and pentaphosphate (IP3, IP4, and IP5) with those of phytic acid (IP6) on growth, development and mineral utilization of young quail. Day-old Japanese quail were fed a purified casein-gelatin control diet containing 20 ppm Zn with 0 or 8.33 mmoles/kg of each inositol phosphate, corresponding to 0.55% of IP6, for a week. As compared with controls, IP6 caused reduced body weight, poor feathering, severe perosis, decreased tibia Zn and ash, and decreased pancreas Zn and liver Mn. IP5 produced all the same adverse effects and tissue mineral changes as those by phytic acid, whereas birds fed IP3 or IP4 were normal. Moreover, IP3 and IP4 caused an increased tibia weight and ash. None of the above effects was produced by feeding inositol or inorganic phosphate. In a second experiment, the inositol phosphates were fed at either 8.33 or 16.66 mmoles/kg diet. Doubling inositol phosphate levels resulted in similar effects as those observed previously. Additionally, IP4 decreased pancreas Zn and IP3 increased tibia Zn. These results indicate that unlike IP6 and IP5, inositol phosphates with 4 or fewer phosphate groups, which can arise from hydrolysis of phytic acid during food processing, have very minor adverse effects but may be beneficial for bone mineralization.

  7. Inositol pyrophosphates modulate hydrogen peroxide signalling.

    PubMed

    Onnebo, Sara Maria Nancy; Saiardi, Adolfo

    2009-09-14

    Inositol pyrophosphates are involved in a variety of cellular functions, but the specific pathways and/or downstream targets remain poorly characterized. In the present study we use Saccharomyces cerevisiae mutants to examine the potential roles of inositol pyrophosphates in responding to cell damage caused by ROS (reactive oxygen species). Yeast lacking kcs1 [the S. cerevisiae IP6K (inositol hexakisphosphate kinase)] have greatly reduced IP7 (diphosphoinositol pentakisphosphate) and IP8 (bisdiphosphoinositol tetrakisphosphate) levels, and display increased resistance to cell death caused by H2O2, consistent with a sustained activation of DNA repair mechanisms controlled by the Rad53 pathway. Other Rad53-controlled functions, such as actin polymerization, appear unaffected by inositol pyrophosphates. Yeast lacking vip1 [the S. cerevisiae PP-IP5K (also known as IP7K, IP7 kinase)] accumulate large amounts of the inositol pyrophosphate IP7, but have no detectable IP8, indicating that this enzyme represents the physiological IP7 kinase. Similar to kcs1Delta yeast, vip1Delta cells showed an increased resistance to cell death caused by H2O2, indicating that it is probably the double-pyrophosphorylated form of IP8 [(PP)2-IP4] which mediates the H2O2 response. However, these inositol pyrophosphates are not involved in directly sensing DNA damage, as kcs1Delta cells are more responsive to DNA damage caused by phleomycin. We observe in vivo a rapid decrease in cellular inositol pyrophosphate levels following exposure to H2O2, and an inhibitory effect of H2O2 on the enzymatic activity of Kcs1 in vitro. Furthermore, parallel cysteine mutagenesis studies performed on mammalian IP6K1 are suggestive that the ROS signal might be transduced by the direct modification of this evolutionarily conserved class of enzymes.

  8. Surfactant phospholipid metabolism

    PubMed Central

    Agassandian, Marianna; Mallampalli, Rama K.

    2012-01-01

    Pulmonary surfactant is essential for life and is comprised of a complex lipoprotein-like mixture that lines the inner surface of the lung to prevent alveolar collapse at the end of expiration. The molecular composition of surfactant depends on highly integrated and regulated processes involving its biosynthesis, remodeling, degradation, and intracellular trafficking. Despite its multicomponent composition, the study of surfactant phospholipid metabolism has focused on two predominant components, disaturated phosphatidylcholine that confers surface-tension lowering activities, and phosphatidylglycerol, recently implicated in innate immune defense. Future studies providing a better understanding of the molecular control and physiological relevance of minor surfactant lipid components are needed. PMID:23026158

  9. Both myo-inositol to chiro-inositol epimerase activities and chiro-inositol to myo-inositol ratios are decreased in tissues of GK type 2 diabetic rats compared to Wistar controls.

    PubMed

    Sun, Tie-hua; Heimark, Douglas B; Nguygen, Thang; Nadler, Jerry L; Larner, Joseph

    2002-05-10

    Previous data from our and other labs demonstrated a decreased chiro-inositol content in urine and tissues of human subjects and animals with type 2 diabetes. In urine this decrease in chiro-inositol was accompanied by an increase in myo-inositol content. Decreased urine levels of chiro-inositol in monkeys were next correlated with the severity of underlying insulin resistance determined by five separate assays. To investigate the decreased chiro-inositol and the accompanying increased myo-inositol excretions in urine in humans and monkeys, we postulated a defect in the epimerization of myo-inositol to chiro-inositol. [(3)H]Myo-inositol was then shown to be converted to [(3)H]chiro-inositol in rats in vivo and in fibroblasts in vitro in a process stimulated by insulin. We next demonstrated that the conversion of [(3)H]myo-inositol to [(3)H]chiro-inositol in vivo was markedly decreased in GK type 2 diabetic rats compared to Wistar controls in liver, muscle, and fat, insulin sensitive tissues. Decreases of 20-25% conversion to baseline levels of under 5% conversion were observed. In the present work, we initially compared the total contents of myo-inositol and chiro-inositol in GK type 2 diabetic rat kidney, liver, and muscle compared to Wistar controls. We demonstrated a consistent decreased total chiro-inositol to myo-inositol ratio in kidney, liver, and muscle compared to controls. We next established the presence of a myo-inositol to chiro-inositol epimerase activity in rat liver cytosol. Enzyme activity was shown to be time and enzyme concentration dependent with a broad pH optimum. It required NADH and NADPH for full activity, which is compatible with its action via an oxido-reductive mechanism. Lastly, we demonstrated that the epimerase enzyme bioactivity was significantly decreased in muscle, liver, and fat cytosolic extracts of GK type 2 diabetic rats versus Wistar controls. Decreased myo-inositol to chiro-inositol epimerase activity may therefore play a

  10. Cancer inhibition by inositol hexaphosphate (IP6) and inositol: from laboratory to clinic.

    PubMed

    Vucenik, Ivana; Shamsuddin, AbulKalam M

    2003-11-01

    Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate that is present in substantial amounts in almost all plant and mammalian cells. It was recently recognized to possess multiple biological functions. A striking anticancer effect of IP6 was demonstrated in different experimental models. Inositol is also a natural constituent possessing moderate anticancer activity. The most consistent and best anticancer results were obtained from the combination of IP6 plus inositol. In addition to reducing cell proliferation, IP6 increases differentiation of malignant cells, often resulting in a reversion to normal phenotype. Exogenously administered IP6 is rapidly taken into the cells and dephosphorylated to lower-phosphate inositol phosphates, which further interfere with signal transduction pathways and cell cycle arrest. Enhanced immunity and antioxidant properties can also contribute to tumor cell destruction. However, the molecular mechanisms underlying this anticancer action are not fully understood. Because it is abundantly present in regular diet, efficiently absorbed from the gastrointestinal tract, and safe, IP6 holds great promise in our strategies for the prevention and treatment of cancer. IP6 plus inositol enhances the anticancer effect of conventional chemotherapy, controls cancer metastases, and improves the quality of life, as shown in a pilot clinical trial. The data strongly argue for the use of IP6 plus inositol in our strategies for cancer prevention and treatment. However, the effectiveness and safety of IP6 plus inositol at therapeutic doses needs to be determined in phase I and phase II clinical trials in humans.

  11. The Effectiveness of Myo-Inositol and D-Chiro Inositol Treatment in Type 2 Diabetes

    PubMed Central

    Di Vieste, Giacoma; Bonomo, Matteo

    2016-01-01

    Inositol has been used as a supplement in treating several pathologies such as PCOS, metabolic syndrome, and gestational diabetes. Both myo-inositol and its isomer d-chiro-inositol showed insulin mimetic effects in conditions of insulin resistance. Type 2 diabetes (T2DM) is a condition typically caused by insulin resistance. There is a lack of evidence of inositol use in T2DM. We evaluated the effectiveness and safety of myo-inositol and d-chiro-inositol treatment in T2DM. This was a pilot study involving a consecutive sample of patients with T2DM with suboptimal glycemic control (HbA1c 7.0–10.0%) already treated with glucose-lowering agents. Patients (23.1% males, mean age of 60.8 ± 11.7 years) took for three months a combination of myo-inositol (550 mg) and d-chiro-inositol (13.8 mg) orally twice a day as add-on supplement to their glucose-lowering drugs. Possible occurrence of side effects was investigated. After three months of treatment fasting blood glucose (192.6 ± 60.2 versus 160.9 ± 36.4; p = 0.02) and HbA1c levels (8.6 ± 0.9 versus 7.7 ± 0.9; p = 0.02) significantly decreased compared to baseline. There was no significant difference in blood pressure, lipid profile, and BMI levels. None of the participants reported side effects. In conclusion, a supplementation with a combination of myo- and d-chiro-inositol is an effective and safe strategy for improving glycemic control in T2DM. PMID:27807448

  12. Synthesis of myo-inositol 1,3,4,5,6-pentakisphosphate from inositol phosphates generated by receptor activation.

    PubMed Central

    Stephens, L R; Hawkins, P T; Barker, C J; Downes, C P

    1988-01-01

    myo-[3H]Inositol 1,3,4,5,6-pentakisphosphate can be made from myo-[3H]inositol 1,4,5-trisphosphate in a rat brain homogenate or soluble fraction. Although D-myo-inositol 3,4,5,6-tetrakisphosphate can be phosphorylated by a soluble rat brain enzyme to give myo-inositol 1,3,4,5,6-pentakisphosphate, it is not an intermediate in the pathway from myo-inositol 1,4,5-trisphosphate. The intermediates in the above pathway are myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4-trisphosphate and myo-inositol 1,3,4,6-tetrakisphosphate [Shears, Parry, Tang, Irvine, Michell & Kirk (1987) Biochem. J. 246, 139-147; Balla, Guillemette, Baukal & Catt (1987) J. Biol. Chem. 262, 9952-9955], and it is catalysed by soluble kinase activities of similar anion-exchange mobility and Mr value. Compounds with chromatographic and chemical properties consistent with the structures myo-inositol 1,3,4,5-tetrakisphosphate, myo-inositol 1,3,4,6-tetrakisphosphate and myo-inositol 3,4,5,6-tetrakisphosphate are present in avian erythrocytes, human 1321 N1 astrocytoma cells and primary-cultured murine bone-marrow-derived macrophages. The amounts of these inositol tetrakisphosphates rise upon muscarinic cholinergic stimulation of the astrocytoma cells or stimulation of macrophages with platelet-activating factor. PMID:2845930

  13. Anti phospholipid syndrome.

    PubMed

    Miah, M T; Hoque, M A; Sutradhar, S R; Mahmood, T; Tarafder, B K

    2009-01-01

    Anti Phospholipid Syndrome (APS) is a relatively new conception of syndrome complex first noticed in 1983. It may be primary or secondary to other diseases like SLE, RA, Systemic sclerosis, behchet's syndrome, temporal arteritis, sjogren's syndrome psoriatic arthropathy etc. Clinical manifestations are consequences of vascular thrombosis and embolism like DVT, pulmonary embolism, stroke, TIA, complication of pregnancy with pregnancy loss. We report a 34 years married female housewife who presented with sudden onset of nausea, vomiting, vertigo, dysphagia, dysarthria and ataxia. She had a chronic leg ulcer. Neurological findings were consistent with lateral medullary syndrome due to stroke though she was normotensive, nondiabetic with normal lipid profile. She had history of two abortions in last three years. Investigations were done accordingly and she fulfilled the diagnostic criteria of APS. No secondary cause was detected after thorough clinical examination and laboratory investigations. She was treated symptomatically along with oral anticoagulation. She improved slowly but steadily.

  14. Chronic treatment with lithium and pretreatment with excess inositol reduce inositol pool size in astrocytes by different mechanisms.

    PubMed

    Wolfson, M; Hertz, E; Belmaker, R H; Hertz, L

    1998-03-16

    Chronic treatment with a lithium salt is the classical treatment for manic-depressive disorder. It is hypothesized that the therapeutic action of lithium is caused by its inhibition of inositol phosphatases which leads to a relative deficiency of inositol and, therefore, an impairment of inositol recycling and production of precursor for the second messengers inositol triphosphate (IP3) and diacylglycerol (DAG). However, peculiarly enough, treatment with high doses of inositol also has an antidepressant effect. In the present work, we have studied the acute and chronic effects of lithium and of excess inositol, in separation or together, on accumulation of 50 microM [3H]inositol (a physiologically relevant concentration) into primary cultures of mouse astrocytes. Two parameters were investigated: (1) rate of unidirectional uptake across the cell membrane (measured during short-term exposure to the radioisotope), and (2) magnitude of the intracellular pool of inositol, equilibrating with extracellular inositol (measured during long-term exposure to the radioisotope). Inositol uptake was highly concentrative and occurred with a Km of approximately 500 microM and a Vmax of 1.5 nmol/min/mg protein. The uptake rate was not affected by either acute or chronic treatment with LiCl (or both), but it was substantially reduced ('down-regulated') after pretreatment with a high concentration of inositol. The inositol pool size was decreased to a similar extent as the uptake rate by previous exposure to excess inositol. In spite of the fact that inositol uptake rate was unaffected by lithium, the magnitude of the inositol pool was significantly decreased by chronic treatment with a pharmacologically relevant concentration of LiCl (1 mM), but not by treatment with lower concentrations. This decrease is likely to reflect a reduction in either inositol synthesis or replenishment of inositol from IP3, due to the inhibition of inositol phosphatases by the lithium ion. In agreement

  15. Comparison of Saccharomyces cerevisiae F-BAR Domain Structures Reveals a Conserved Inositol Phosphate Binding Site

    DOE PAGES

    Moravcevic, Katarina; Alvarado, Diego; Schmitz, Karl R.; ...

    2015-01-22

    F-BAR domains control membrane interactions in endocytosis, cytokinesis, and cell signaling. Although they are generally thought to bind curved membranes containing negatively charged phospholipids, numerous functional studies argue that differences in lipid-binding selectivities of F-BAR domains are functionally important. Here in this paper, we compare membrane-binding properties of the Saccharomyces cerevisiae F-BAR domains in vitro and in vivo. Whereas some F-BAR domains (such as Bzz1p and Hof1p F-BARs) bind equally well to all phospholipids, the F-BAR domain from the RhoGAP Rgd1p preferentially binds phosphoinositides. We determined X-ray crystal structures of F-BAR domains from Hof1p and Rgd1p, the latter bound tomore » an inositol phosphate. The structures explain phospholipid-binding selectivity differences and reveal an F-BAR phosphoinositide binding site that is fully conserved in a mammalian RhoGAP called Gmip and is partly retained in certain other F-BAR domains. In conclusion, our findings reveal previously unappreciated determinants of F-BAR domain lipid-binding specificity and provide a basis for its prediction from sequence.« less

  16. 21 CFR 582.5370 - Inositol.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Inositol. 582.5370 Section 582.5370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements...

  17. 21 CFR 582.5370 - Inositol.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Inositol. 582.5370 Section 582.5370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1...

  18. 21 CFR 582.5370 - Inositol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Inositol. 582.5370 Section 582.5370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1...

  19. 21 CFR 184.1370 - Inositol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Inositol. 184.1370 Section 184.1370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD... the Food Chemicals Codex, 3d Ed. (1981), p. 150, which is incorporated by reference. Copies are...

  20. 21 CFR 582.5370 - Inositol.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Inositol. 582.5370 Section 582.5370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1...

  1. 21 CFR 582.5370 - Inositol.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Inositol. 582.5370 Section 582.5370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1...

  2. Myo-Inositol content determined by myo-inositol biosynthesis and oxidation in blueberry fruit.

    PubMed

    Song, Fangyuan; Su, Hongyan; Yang, Nan; Zhu, Luying; Cheng, Jieshan; Wang, Lei; Cheng, Xianhao

    2016-11-01

    Myo-inositol metabolism in plant edible organs has become the focus of many recent studies because of its benefits to human health and unique functions in plant development. In this study, myo-inositol contents were analyzed during the development of two blueberry cultivars, cv 'Berkeley' and cv 'Bluecrop'. Furthermore, two VcMIPS 1/2 (Vaccinium corymbosum MIPS) genes, one VcIMP (Vaccinium corymbosum IMP) gene and one VcMIOX (Vaccinium corymbosum MIOX) gene were isolated for the first time from blueberry. The expression patterns of VcMIPS2, VcIMP and VcMIOX genes showed a relationship with the change profiles of myo-inositol content during fruit ripening. The results were further confirmed by the analyses of the enzyme activity. Results indicated that both myo-inositol biosynthesis and oxidation played important roles in determining of myo-inositol levels during the development of blueberry. To our knowledge, this report is the first to discuss myo-inositol levels in fruits in terms of biosynthesis and catabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Enzymes of myo-inositol and inositol lipid metabolism in rats with streptozotocin-induced diabetes.

    PubMed Central

    Whiting, P H; Palmano, K P; Hawthorne, J N

    1979-01-01

    Diabetes, with only mild ketosis, was induced in male rats by a single injection of streptozotocin. After 12 weeks the specific activities of enzymes concerned with the metabolism of inositol and of inositol lipids were measured in various tissues. Inositol 1-phosphate synthase (EC 5.5.1.4) was most active in testis and the activity was significantly less in diabetic rats than in controls on a similar diet. Inositol oxygenase (EC 1.13.99.1), which converts myo-inositol into glucuronic acid, was also less active in kidney from diabetic animals. CDP-diacylglycerol-inositol phosphatidyltransferase (EC 2.7.8.11) and phosphatidylinositol 4-phosphate kinase (EC 2.7.1.68) showed decreased specific activities in brain and sciatic nerve of diabetic rats. By contrast the diabetic state did not affect the specific activities of phosphatidylinositol kinase (EC 2.7.1.67) or phosphatidylinositol 4,5-bisphosphate phosphatase (EC 3.1.3.36) in these tissues. The results are discussed in relation to diabetic neuropathy. PMID:224862

  4. D-chiro-inositol metabolism in diabetes mellitus.

    PubMed

    Ostlund, R E; McGill, J B; Herskowitz, I; Kipnis, D M; Santiago, J V; Sherman, W R

    1993-11-01

    D-chiro-inositol is a rare inositol isomer present in inositol phosphoglycans which are proposed mediators of insulin action. To study D-chiro-inositol metabolism in diabetes mellitus, a sensitive and specific assay was developed using negative-ion chemical ionization gas chromatography/mass spectrometry. Median urinary D-chiro-inositol excretion, which was 2.1 mumol/day in nondiabetics, was substantially increased to 12 mumol/day in non-insulin-dependent diabetes (P < 0.0001) and to 74 mumol/day in insulin-dependent diabetes (P < 0.0001). Urinary D-chiro-inositol was strongly correlated with fasting plasma glucose (r = 0.568, P < 0.0001), glycated hemoglobin (r = 0.529, P < 0.0001), and urinary glucose (r = 0.368, P = 0.01). The renal clearance of D-chiro-inositol was selectively elevated in both non-insulin-dependent and insulin-dependent diabetes when compared with the clearances of L-chiro-inositol or myo-inositol and exceeded the glomerular filtration rate in 71% of the diabetics but in none of the nondiabetics. In poorly controlled diabetic patients insulin treatment reduced urinary D-chiro-inositol losses by 63% and increased plasma levels by 8.8-fold. The metabolism of D-chiro-inositol is abnormal in diabetes and appears to be influenced by short- and long-term metabolic control.

  5. Content of methylated inositols in familiar edible plants.

    PubMed

    Negishi, Osamu; Mun'im, Abdul; Negishi, Yukiko

    2015-03-18

    Familiar plants contain large amounts of inositols; soybean, white clover, red clover, bush clover, locust tree, wisteria, and kudzu of the legume family contain pinitol (3-O-methyl-chiro-inositol) at approximately 200-600 mg/100 g fresh weight (FW). The contents of pinitol in other plants were 260 mg/100 g FW for sticky mouse-ear, 275 mg/100 g FW for chickweed, and 332 mg/100 g FW for ginkgo. chiro-Inositol of 191 and 156 mg/100 g FW was also found in dandelion and Japanese mallotus, respectively. Ononitol (4-O-methyl-myo-inositol) of 166 mg/100 g FW was found in sticky mouse-ear. Furthermore, young leaves of ginkgo contained sequoyitol (5-O-methyl-myo-inositol) of 287 mg/100 g FW. Hydroxyl radical scavenging activities of the methylated inositols were higher than those of the original inositols. Effective uses of these familiar edible plants are expected to promote good health.

  6. The inositol phosphate/diacylglycerol signalling pathway in Trypanosoma cruzi.

    PubMed Central

    Docampo, R; Pignataro, O P

    1991-01-01

    Using [32P]Pi and [3H]inositol as precursors, we have detected the presence of phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, and their derivatives inositol phosphate, inositol 1,4-bisphosphate and inositol 1,4,5-trisphosphate respectively, in Trypanosoma cruzi epimastigotes. Using digitonin-permeabilized cells it was possible to detect a stimulation in the formation of inositol 1,4,5-trisphosphate and inositol 1,4-bisphosphate as well as an increased generation of diacylglycerol in the presence of 1 mM-CaCl2. These results are consistent with the operation of a functional inositol phosphate/diacylglycerol pathway in T. cruzi, and constitute the first demonstration of the presence and activation of this pathway in a parasitic protozoan. These results also indicate that this pathway is conserved during evolution from lower to higher eukaryotic organisms. Images Fig. 1. PMID:2025225

  7. Inositol pyrophosphates inhibit synaptotagmin-dependent exocytosis

    PubMed Central

    Lee, Tae-Sun; Lee, Joo-Young; Kyung, Jae Won; Yang, Yoosoo; Park, Seung Ju; Lee, Seulgi; Pavlovic, Igor; Kong, Byoungjae; Jho, Yong Seok; Jessen, Henning J.; Kweon, Dae-Hyuk; Shin, Yeon-Kyun; Kim, Sung Hyun; Yoon, Tae-Young; Kim, Seyun

    2016-01-01

    Inositol pyrophosphates such as 5-diphosphoinositol pentakisphosphate (5-IP7) are highly energetic inositol metabolites containing phosphoanhydride bonds. Although inositol pyrophosphates are known to regulate various biological events, including growth, survival, and metabolism, the molecular sites of 5-IP7 action in vesicle trafficking have remained largely elusive. We report here that elevated 5-IP7 levels, caused by overexpression of inositol hexakisphosphate (IP6) kinase 1 (IP6K1), suppressed depolarization-induced neurotransmitter release from PC12 cells. Conversely, IP6K1 depletion decreased intracellular 5-IP7 concentrations, leading to increased neurotransmitter release. Consistently, knockdown of IP6K1 in cultured hippocampal neurons augmented action potential-driven synaptic vesicle exocytosis at synapses. Using a FRET-based in vitro vesicle fusion assay, we found that 5-IP7, but not 1-IP7, exhibited significantly higher inhibitory activity toward synaptic vesicle exocytosis than IP6. Synaptotagmin 1 (Syt1), a Ca2+ sensor essential for synaptic membrane fusion, was identified as a molecular target of 5-IP7. Notably, 5-IP7 showed a 45-fold higher binding affinity for Syt1 compared with IP6. In addition, 5-IP7–dependent inhibition of synaptic vesicle fusion was abolished by increasing Ca2+ levels. Thus, 5-IP7 appears to act through Syt1 binding to interfere with the fusogenic activity of Ca2+. These findings reveal a role of 5-IP7 as a potent inhibitor of Syt1 in controlling the synaptic exocytotic pathway and expand our understanding of the signaling mechanisms of inositol pyrophosphates. PMID:27364007

  8. Analysis of Dictyostelium discoideum inositol pyrophosphate metabolism by gel electrophoresis.

    PubMed

    Pisani, Francesca; Livermore, Thomas; Rose, Giuseppina; Chubb, Jonathan Robert; Gaspari, Marco; Saiardi, Adolfo

    2014-01-01

    The social amoeba Dictyostelium discoideum was instrumental in the discovery and early characterization of inositol pyrophosphates, a class of molecules possessing highly-energetic pyrophosphate bonds. Inositol pyrophosphates regulate diverse biological processes and are attracting attention due to their ability to control energy metabolism and insulin signalling. However, inositol pyrophosphate research has been hampered by the lack of simple experimental procedures to study them. The recent development of polyacrylamide gel electrophoresis (PAGE) and simple staining to resolve and detect inositol pyrophosphate species has opened new investigative possibilities. This technology is now commonly applied to study in vitro enzymatic reactions. Here we employ PAGE technology to characterize the D. discoideum inositol pyrophosphate metabolism. Surprisingly, only three major bands are detectable after resolving acidic extract on PAGE. We have demonstrated that these three bands correspond to inositol hexakisphosphate (IP₆ or Phytic acid) and its derivative inositol pyrophosphates, IP₇ and IP₈. Biochemical analyses and genetic evidence were used to establish the genuine inositol phosphate nature of these bands. We also identified IP₉ in D. discoideum cells, a molecule so far detected only from in vitro biochemical reactions. Furthermore, we discovered that this amoeba possesses three different inositol pentakisphosphates (IP₅) isomers, which are largely metabolised to inositol pyrophosphates. Comparison of PAGE with traditional Sax-HPLC revealed an underestimation of the cellular abundance of inositol pyrophosphates by traditional methods. In fact our study revealed much higher levels of inositol pyrophosphates in D. discoideum in the vegetative state than previously detected. A three-fold increase in IP₈ was observed during development of D. discoideum a value lower that previously reported. Analysis of inositol pyrophosphate metabolism using ip6k null amoeba

  9. Analysis of Dictyostelium discoideum Inositol Pyrophosphate Metabolism by Gel Electrophoresis

    PubMed Central

    Pisani, Francesca; Livermore, Thomas; Rose, Giuseppina; Chubb, Jonathan Robert; Gaspari, Marco; Saiardi, Adolfo

    2014-01-01

    The social amoeba Dictyostelium discoideum was instrumental in the discovery and early characterization of inositol pyrophosphates, a class of molecules possessing highly-energetic pyrophosphate bonds. Inositol pyrophosphates regulate diverse biological processes and are attracting attention due to their ability to control energy metabolism and insulin signalling. However, inositol pyrophosphate research has been hampered by the lack of simple experimental procedures to study them. The recent development of polyacrylamide gel electrophoresis (PAGE) and simple staining to resolve and detect inositol pyrophosphate species has opened new investigative possibilities. This technology is now commonly applied to study in vitro enzymatic reactions. Here we employ PAGE technology to characterize the D. discoideum inositol pyrophosphate metabolism. Surprisingly, only three major bands are detectable after resolving acidic extract on PAGE. We have demonstrated that these three bands correspond to inositol hexakisphosphate (IP6 or Phytic acid) and its derivative inositol pyrophosphates, IP7 and IP8. Biochemical analyses and genetic evidence were used to establish the genuine inositol phosphate nature of these bands. We also identified IP9 in D. discoideum cells, a molecule so far detected only from in vitro biochemical reactions. Furthermore, we discovered that this amoeba possesses three different inositol pentakisphosphates (IP5) isomers, which are largely metabolised to inositol pyrophosphates. Comparison of PAGE with traditional Sax-HPLC revealed an underestimation of the cellular abundance of inositol pyrophosphates by traditional methods. In fact our study revealed much higher levels of inositol pyrophosphates in D. discoideum in the vegetative state than previously detected. A three-fold increase in IP8 was observed during development of D. discoideum a value lower that previously reported. Analysis of inositol pyrophosphate metabolism using ip6k null amoeba revealed

  10. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following precedence...

  11. Phospholipid and glycolipid composition of acidocalcisomes of Trypanosoma cruzi.

    PubMed

    Salto, María Laura; Kuhlenschmidt, Theresa; Kuhlenschmidt, Mark; de Lederkremer, Rosa M; Docampo, Roberto

    2008-04-01

    Highly purified acidocalcisomes from Trypanosoma cruzi epimastigotes were obtained by differential centrifugation and iodixanol gradient ultracentrifugation. Lipid analysis of acidocalcisomes revealed the presence of low amounts of 3beta-hydroxysterols and predominance of phospholipids. Alkylacyl phosphatidylinositol (16:0/18:2), diacyl phosphatidylinositol (18:0/18:2), diacyl phosphatidylcholine (16:0/18:2; 16:1/18:2; 16:2/18:2; 18:1/18:2 and 18:2/18:2), and diacyl phosphatidylethanolamine (16:0/18:2 and 16:1/18:2) were the only phospholipids characterized by electrospray ionization-mass spectrometry (ESI-MS). Incubation of epimastigotes with [(3)H]-mannose and isolation of acidocalcisomes allowed the detection of a glycoinositolphospholipid (GIPL) in these organelles. The sugar content of the acidocalcisomal GIPL was similar to that of the GIPL present in a microsomal fraction but the amount of galactofuranose and inositol with respect to the other monosaccharides was lower, suggesting a different chemical structure. Taken together, these results indicate that acidocalcisomes of T. cruzi have a distinct lipid and carbohydrate composition.

  12. Phospholipid and glycolipid composition of acidocalcisomes of Trypanosoma cruzi

    PubMed Central

    Salto, María Laura; Kuhlenschmidt, Theresa; Kuhlenschmidt, Mark; de Lederkremer, Rosa M.; Docampo, Roberto

    2008-01-01

    Highly purified acidocalcisomes from Trypanosoma cruzi epimastigotes were obtained by differential centrifugation and iodixanol gradient ultracentrifugation. Lipid analysis of acidocalcisomes revealed the presence of low amounts of 3β-hydroxysterols and predominance of phospholipids. Alkylacyl phosphatidylinositol (16:0/18:2), diacyl phosphatidylinositol (18:0/18:2), diacyl phosphatidylcholine (16:0/18:2; 16:1/18:2; 16:2/18:2, 18:1/18:2, and 18:2/18:2), and diacyl phosphatidylethanolamine (16:0/18:2 and 16:1/18:2) were the only phospholipids characterized by electrospray ionization-mass spectrometry (ESI-MS). Incubation of epimastigotes with [3H]-mannose and isolation of acidocalcisomes allowed the detection of a glycoinositolphospholipid (GIPL) in these organelles. The sugar content of the acidocalcisomal GIPL was similar to that of the GIPL present in a microsomal fraction but the amount of galactofuranose and inositol with respect to the other monosaccharides was lower, suggesting a different chemical structure. Taken together, these results indicate that acidocalcisomes of T. cruzi have a distinct lipid and carbohydrate composition. PMID:18207579

  13. Effect of transforming growth factor-alpha on inositol phospholipid metabolism in human epidermoid carcinoma cells

    SciTech Connect

    Kato, M.; Takenawa, T.; Twardzik, D.R.

    1988-08-01

    Transforming growth factor-alpha (TGF-alpha) stimulates (in a dose-dependent manner) the incorporation of (/sup 32/P)Pi into phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidic acid (PA) in the human epidermoid carcinoma cell line (A431). The effect of TGF-alpha on the incorporation was found to be similar to that of EGF. On the other hand, a striking difference in the activation of diacylglycerol (DG) kinase activity was seen between TGF-alpha and EGF. At least 100 times more TGF-alpha was required to achieve maximal stimulation of DG kinase activity relative to EGF. These results suggest that the activation of DG kinase by TGF-alpha may involve a mechanism independent from or subsequent to activation of the EGF receptor.

  14. A cell factory of Bacillus subtilis engineered for the simple bioconversion of myo-inositol to scyllo-inositol, a potential therapeutic agent for Alzheimer's disease

    PubMed Central

    2011-01-01

    Background A stereoisomer of inositol, scyllo-inositol, is known as a promising therapeutic agent for Alzheimer's disease, since it prevents the accumulation of beta-amyloid deposits, a hallmark of the disease. However, this compound is relatively rare in nature, whereas another stereoisomer of inositol, myo-inositol, is abundantly available. Results Bacillus subtilis possesses a unique inositol metabolism involving both stereoisomers. We manipulated the inositol metabolism in B. subtilis to permit the possible bioconversion from myo-inositol to scyllo-inositol. Within 48 h of cultivation, the engineered strain was able to convert almost half of 10 g/L myo-inositol to scyllo-inositol that accumulated in the culture medium. Conclusions The engineered B. subtilis serves as a prototype of cell factory enabling a novel and inexpensive supply of scyllo-inositol. PMID:21896210

  15. Partial purification and characterization of indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (indoleacetic acid-inositol synthase)

    NASA Technical Reports Server (NTRS)

    Kesy, J. M.; Bandurski, R. S.

    1990-01-01

    A procedure is described for the purification of the enzyme indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (IAA-myo-inositol synthase). This enzyme catalyzes the transfer of indol-3-ylacetate from 1-0-indol-3-ylacetyl-beta-d-glucose to myo-inositol to form indol-3-ylacetyl-myo-inositol and glucose. A hexokinase or glucose oxidase based assay system is described. The enzyme has been purified approximately 16,000-fold, has an isoelectric point of pH 6.1 and yields three catalytically inactive bands upon acrylamide gel electrophoresis of the native protein. The enzyme shows maximum transferase activity with myo-inositol but shows some transferase activity with scyllo-inositol and myo-inosose-2. No transfer of IAA occurs with myo-inositol-d-galactopyranose, cyclohexanol, mannitol, or glycerol as acyl acceptor. The affinity of the enzyme for 1-0-indol-3-ylacetyl-beta-d-glucose is, Km = 30 micromolar, and for myo-inositol is, Km = 4 millimolar. The enzyme does not catalyze the exchange incorporation of glucose into IAA-glucose indicating the reaction mechanism involves binding of IAA glucose to the enzyme with subsequent hydrolytic cleavage of the acyl moiety by the hydroxyl of myo-inositol to form IAA myo-inositol ester.

  16. Partial purification and characterization of indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (indoleacetic acid-inositol synthase)

    NASA Technical Reports Server (NTRS)

    Kesy, J. M.; Bandurski, R. S.

    1990-01-01

    A procedure is described for the purification of the enzyme indol-3-ylacetylglucose:myo-inositol indol-3-ylacetyltransferase (IAA-myo-inositol synthase). This enzyme catalyzes the transfer of indol-3-ylacetate from 1-0-indol-3-ylacetyl-beta-d-glucose to myo-inositol to form indol-3-ylacetyl-myo-inositol and glucose. A hexokinase or glucose oxidase based assay system is described. The enzyme has been purified approximately 16,000-fold, has an isoelectric point of pH 6.1 and yields three catalytically inactive bands upon acrylamide gel electrophoresis of the native protein. The enzyme shows maximum transferase activity with myo-inositol but shows some transferase activity with scyllo-inositol and myo-inosose-2. No transfer of IAA occurs with myo-inositol-d-galactopyranose, cyclohexanol, mannitol, or glycerol as acyl acceptor. The affinity of the enzyme for 1-0-indol-3-ylacetyl-beta-d-glucose is, Km = 30 micromolar, and for myo-inositol is, Km = 4 millimolar. The enzyme does not catalyze the exchange incorporation of glucose into IAA-glucose indicating the reaction mechanism involves binding of IAA glucose to the enzyme with subsequent hydrolytic cleavage of the acyl moiety by the hydroxyl of myo-inositol to form IAA myo-inositol ester.

  17. A new inositol triester from Taraxacum mongolicum.

    PubMed

    Liu, Jifeng; Zhang, Nenling; Liu, Mengqi

    2014-01-01

    One new inositol triester, 4,5,6-tri-O-p-hydroxyphenylacetyl-chiro-inositol (1), was isolated from the ethanolic extract of Taraxacum mongolicum, along with two known compounds, 11β,13-dihydrotaraxinic acid (2) and taraxinic acid β-d-glucopyranosyl ester (3). The isolates were tested for their anti-hepatitis B virus (HBV) activities; 11β,13-dihydrotaraxinic acid (2) exhibited an IC50 value of 0.91 mM inhibiting the secretion of the HBV surface antigen and an IC50 value of 0.34 mM inhibiting the secretion of the HBV e antigen using HBV transfected Hep G2.2.15 cell line.

  18. Supported phospholipid bilayers.

    PubMed Central

    Tamm, L. K.; McConnell, H. M.

    1985-01-01

    Phospholipid bilayers have been formed on glass, quartz, and silicon surfaces by a sequential transfer of two monolayers at a pressure of approximately 40 dyn/cm from the air-water interface to the solid substrates. Lateral diffusion measurements of L-alpha-dipalmitoylphosphatidylcholine (DPPC) bilayers supported on oxidized silicon wafers reveal two sharp phase transitions at temperatures similar to those found in multilayer systems with several different techniques. The diffusion measurements obtained using fluorescence recovery after pattern photobleaching provide evidence for the existence of an intermediate (probably P beta' or ripple) phase in single bilayers. While in the intermediate and high temperature (liquid-crystalline L alpha) phase, the diffusion coefficients do not vary very much with temperature, a strong temperature dependence is observed in the low temperature (gel L beta') phase. This is attributed to defect-mediated diffusion. Lipids in silicon supported bilayers made from L-alpha-dioleoylphosphatidylcholine (DOPC) or L-alpha-dimyristoylphosphatidylcholine (DMPC) diffuse rapidly above their respective chain-melting transition temperatures. Arrhenius plots show straight lines with activation energies of 40.9 and 43.7 kJ/mol, respectively. Supported DPPC bilayers on oxidized silicon form long tubular liposomes when heated through their oxidized silicon form long tubular liposomes when heated through their chain-melting-phase transition, as viewed with epifluorescence microscopy. It is suggested that this is a consequence of the expansion of the lipid on the fixed solid support. Conversely, DOPC bilayers form large void areas on this substrate upon cooling. Large circular membrane defects (holes) are observed under rapid coating conditions. The formation of these defects is modulated by including small amounts of lyso-L-palmitoyl phosphatidylcholine in the DMPC-supported bilayers. A simple model describes the dependence of hole size and hole

  19. Prevention of Prostate Cancer by Inositol Hexaphosphate

    DTIC Science & Technology

    2004-02-01

    growth factor signaling pathways thereby inhibit growth. A large number of studies have pointed out that inositol hexaphosphate ( IP6 ) could have...beneficial effect on variety of cancers. The specific aims of this proposal are to determine (1) the in vivo effects of IP6 on the growth of PCa (2) the...efficacy of IP6 in inhibiting growth factor-induced DNA synthesis of the PCa cells in vitro, and (3) the molecular mechanisms by which IP6 inhibit growth

  20. Candida albicans OPI1 Regulates Filamentous Growth and Virulence in Vaginal Infections, but Not Inositol Biosynthesis

    PubMed Central

    Chen, Ying-Lien; de Bernardis, Flavia; Yu, Shang-Jie; Sandini, Silvia; Kauffman, Sarah; Tams, Robert N.; Bethea, Emily; Reynolds, Todd B.

    2015-01-01

    ScOpi1p is a well-characterized transcriptional repressor and master regulator of inositol and phospholipid biosynthetic genes in the baker’s yeast Saccharomyces cerevisiae. An ortholog has been shown to perform a similar function in the pathogenic fungus Candida glabrata, but with the distinction that CgOpi1p is essential for growth in this organism. However, in the more distantly related yeast Yarrowia lipolytica, the OPI1 homolog was not found to regulate inositol biosynthesis, but alkane oxidation. In Candida albicans, the most common cause of human candidiasis, its Opi1p homolog, CaOpi1p, has been shown to complement a S. cerevisiae opi1∆ mutant for inositol biosynthesis regulation when heterologously expressed, suggesting it might serve a similar role in this pathogen. This was tested in the pathogen directly in this report by disrupting the OPI1 homolog and examining its phenotypes. It was discovered that the OPI1 homolog does not regulate INO1 expression in C. albicans, but it does control SAP2 expression in response to bovine serum albumin containing media. Meanwhile, we found that CaOpi1 represses filamentous growth at lower temperatures (30°C) on agar, but not in liquid media. Although, the mutant does not affect virulence in a mouse model of systemic infection, it does affect virulence in a rat model of vaginitis. This may be because Opi1p regulates expression of the SAP2 protease, which is required for rat vaginal infections. PMID:25602740

  1. Inositol hexakisphosphate kinase products contain diphosphate and triphosphate groups.

    PubMed

    Draskovic, Petra; Saiardi, Adolfo; Bhandari, Rashna; Burton, Adam; Ilc, Gregor; Kovacevic, Miroslav; Snyder, Solomon H; Podobnik, Marjetka

    2008-03-01

    Eukaryotic cells produce a family of diverse inositol polyphosphates (IPs) containing pyrophosphate bonds. Inositol pyrophosphates have been linked to a wide range of cellular functions, and there is growing evidence that they act as second messengers. Inositol hexakisphosphate kinase (IP6K) is able to convert the natural substrates inositol pentakisphosphate (IP 5) and inositol hexakisphosphate (IP 6) to several products with an increasing number of phospho-anhydride bonds. In this study, we structurally analyzed IPs synthesized by three mammalian isoforms of IP6K from IP 5 and IP 6. The NMR and mass analyses showed a number of products with diverse, yet specific, stereochemistry, defined by the architecture of IP6K's active site. We now report that IP6K synthesizes both pyrophosphate (diphospho) as well as triphospho groups on the inositol ring. All three IP6K isoforms share the same activities both in vitro and in vivo.

  2. Inositols in the Treatment of Insulin-Mediated Diseases

    PubMed Central

    Muscogiuri, Giovanna; Palomba, Stefano

    2016-01-01

    A growing body of research is currently focused on the role of inositol isomers and in particular myo-inositol (MYO-INS) and D-chiroinositol (DCI) in the treatment of insulin resistance states. Both isomers have been shown to exert insulin-mimetic action and to lower postprandial glucose. Further, insulin resistance-related diseases were associated to derangements in inositol metabolism. Thus, the aim of this review is to provide current evidence on the potential benefits of inositol isomers (MYO-INS and DCI) in the treatment of disease associated to insulin resistance such as polycystic ovary syndrome (PCOS), gestational diabetes, and metabolic syndrome. Finally, molecular insights into inositol insulin-sensitizing effects will be covered focusing on the possible role of inositol glycans as insulin second messengers. PMID:27688754

  3. Inositol lipids: from an archaeal origin to phosphatidylinositol 3,5-bisphosphate faults in human disease.

    PubMed

    Michell, Robert H

    2013-12-01

    The last couple of decades have seen an extraordinary transformation in our knowledge and understanding of the multifarious biological roles of inositol phospholipids. Herein, I briefly consider two topics. The first is the role that recently acquired biochemical and genomic information - especially from archaeons - has played in illuminating the possible evolutionary origins of the biological employment of inositol in lipids, and some questions that these studies raise about the 'classical' biosynthetic route to phosphatidylinositol. The second is the growing recognition of the importance in eukaryotic cells of phosphatidylinositol 3,5-bisphosphate. Phosphatidylinositol 3,5-bisphosphate only entered our phosphoinositide consciousness quite recently, but it is speedily gathering a plethora of roles in diverse cellular processes and diseases thereof. These include: control of endolysosomal vesicular trafficking and of the activity of ion channels and pumps in the endolysosomal compartment; control of constitutive and stimulated protein traffic to and from plasma membrane subdomains; control of the nutrient and stress-sensing target of rapamycin complex 1 pathway (TORC1); and regulation of key genes in some central metabolic pathways.

  4. Effects of Inositol(s) in Women with PCOS: A Systematic Review of Randomized Controlled Trials

    PubMed Central

    Nestler, John E.; Kamenov, Zdravko A.; Prapas, Nikos; Facchinetti, Fabio

    2016-01-01

    Polycystic ovary syndrome (PCOS) is a common endocrine disorder, with complex etiology and pathophysiology, which remains poorly understood. It affects about 5–10% of women of reproductive age who typically suffer from obesity, hyperandrogenism, ovarian dysfunction, and menstrual irregularity. Indeed, PCOS is the most common cause of anovulatory infertility in industrialized nations, and it is associated with insulin resistance, type 2 diabetes mellitus, and increased cardiovascular risk. Although insulin resistance is not included as a criterion for diagnosis, it is a critical pathological condition of PCOS. The purpose of this systematic review is the analysis of recent randomized clinical trials of inositol(s) in PCOS, in particular myo- and D-chiro-inositol, in order to better elucidate their physiological involvement in PCOS and potential therapeutic use, alone and in conjunction with assisted reproductive technologies, in the clinical treatment of women with PCOS. PMID:27843451

  5. The D-chiro-inositol paradox in the ovary.

    PubMed

    Carlomagno, Gianfranco; Unfer, Vittorio; Roseff, Scott

    2011-06-30

    The D-chiro-inositol-to-myo-inositol ratio is regulated by an insulin-dependent epimerase. Enzyme activity varies among tissues, likely owing to the specific needs of the two different molecules. We hypothesize that in the ovaries of polycystic ovary syndrome patients, epimerase activity is enhanced, leading to a local myo-inositol deficiency which in turn is responsible for the poor oocyte quality.

  6. Interactions of amelogenin with phospholipids

    DOE PAGES

    Bekshe Lokappa, Sowmya; Chandrababu, Karthik Balakrishna; Dutta, Kaushik; ...

    2014-11-22

    Amelogenin protein has the potential to interact with other enamel matrix proteins, mineral, and cell surfaces. In this paper, we investigated the interactions of recombinant amelogenin rP172 with small unilamellar vesicles as model membranes, toward the goal of understanding the mechanisms of amelogenin–cell interactions during amelogenesis. Dynamic light scattering (DLS), fluorescence spectroscopy, circular dichroism (CD), and nuclear magnetic resonance (NMR) were used. In the presence of phospholipid vesicles, a blue shift in the Trp fluorescence emission maxima of rP172 was observed (~334 nm) and the Trp residues of rP172 were inaccessible to the aqueous quencher acrylamide. DLS studies indicated complexationmore » of rP172 and phospholipids, although the possibility of fusion of phospholipids following amelogenin addition cannot be ruled out. NMR and CD studies revealed a disorder–order transition of rP172 in a model membrane environment. Strong fluorescence resonance energy transfer from Trp in rP172 to DNS-bound-phospholipid was observed, and fluorescence polarization studies indicated that rP172 interacted with the hydrophobic core region of model membranes. Finally, our data suggest that amelogenin has ability to interact with phospholipids and that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities.« less

  7. Interactions of amelogenin with phospholipids

    SciTech Connect

    Bekshe Lokappa, Sowmya; Chandrababu, Karthik Balakrishna; Dutta, Kaushik; Perovic, Iva; Evans, John Spencer; Moradian-Oldak, Janet

    2014-11-22

    Amelogenin protein has the potential to interact with other enamel matrix proteins, mineral, and cell surfaces. In this paper, we investigated the interactions of recombinant amelogenin rP172 with small unilamellar vesicles as model membranes, toward the goal of understanding the mechanisms of amelogenin–cell interactions during amelogenesis. Dynamic light scattering (DLS), fluorescence spectroscopy, circular dichroism (CD), and nuclear magnetic resonance (NMR) were used. In the presence of phospholipid vesicles, a blue shift in the Trp fluorescence emission maxima of rP172 was observed (~334 nm) and the Trp residues of rP172 were inaccessible to the aqueous quencher acrylamide. DLS studies indicated complexation of rP172 and phospholipids, although the possibility of fusion of phospholipids following amelogenin addition cannot be ruled out. NMR and CD studies revealed a disorder–order transition of rP172 in a model membrane environment. Strong fluorescence resonance energy transfer from Trp in rP172 to DNS-bound-phospholipid was observed, and fluorescence polarization studies indicated that rP172 interacted with the hydrophobic core region of model membranes. Finally, our data suggest that amelogenin has ability to interact with phospholipids and that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities.

  8. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  9. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  10. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  11. 47 CFR 213.5 - Precedence designators.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Precedence designators. 213.5 Section 213.5 Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL GOVERNMENT AND PUBLIC CORRESPONDENCE TELECOMMUNICATIONS PRECEDENCE SYSTEM § 213.5 Precedence designators. (a) The following...

  12. The “Other” Inositols and Their Phosphates: Synthesis, Biology and Medicine (with Recent Advances in myo-Inositol Chemistry)

    PubMed Central

    Thomas, Mark P; Mills, Stephen J; Potter, Barry V L

    2016-01-01

    Cell signalling via inositol phosphates, eg the second messenger myo-inositol 1,4,5-trisphosphate, and phosphoinositides comprises a huge field of biology. Of nine 1,2,3,4,5,6-cyclohexanehexol isomers, myo-inositol is pre-eminent, with “other” inositols (cis-, epi-, allo-, muco-, neo-, l-chiro-, d-chiro- and scyllo-) and derivatives rarer or thought not to exist in nature. However, recently, neo- and d-chiro-inositol hexakisphosphates were revealed in both terrestrial and aquatic ecosystems, highlighting the paucity of knowledge of the origins and potential biological functions of such stereoisomers, a prevalent group of environmental organic phosphates, and their parent inositols. Some “other” inositols are medically relevant, e.g. scyllo-inositol (neurodegenerative diseases), and d-chiro-inositol (diabetes). It is timely to consider exploration of roles and applications of “other” isomers and their derivatives, likely by exploiting techniques now well developed for the myo-series. PMID:26694856

  13. [Phospholipids: properties and health effects].

    PubMed

    Torres García, Jairo; Durán Agüero, Samuel

    2014-09-12

    Phospholipids are amphipathic lipids, which are found in all the cell membranes, organized as a lipid bilayer. They belong to the glycerol-derived lipids, showing a similar structure as triglycerides. The current interest of them comes from its effectiveness to incorporate different fatty acids in the cell membrane, as they exhibit better absorption and utilization than triglycerides. In this paper, the bibliographical data published about the benefits of the phospholipids in inflammatory processes, cancer, cardiovascular diseases, neurological disorders, liver disease and as an antioxidants transporter is reviewed.

  14. Growth hormone releasing hexapeptide (GHRP-6) activates the inositol (1,4,5)-trisphosphate/diacylglycerol pathway in rat anterior pituitary cells.

    PubMed

    Mau, S E; Witt, M R; Bjerrum, O J; Saermark, T; Vilhardt, H

    1995-01-01

    Growth hormone-releasing hexapeptide (GHRP-6) is known to stimulate secretion of growth hormone (GH) in vivo and in vitro in a variety of species. However, the cellular effects of GHRP-6 remain largely unknown. We have tested the influence of GHRP-6 on the inositol phospholipid second messenger system in cultured anterior pituitary cells. Cultured pituitary cells responded upon challenge with GHRP-6 with a dose-dependent release of GH. Moreover, incubation of GHRP-6 with pituitary cell cultures labelled with myo-[3H]inositol resulted in a dose-dependent rise in [3H]inositol phosphates. Brief stimulation of pituitary cells with GHRP-6 increased phosphorylation of MBP4-14, a specific protein kinase C substrate, when incubated with the cytosol- or plasma membrane fraction from the stimulated cells. Furthermore, introduction of MBP4-14 into the cytosol in digitonin permeabilized pituitary cells caused increased phosphorylation of this substrate. GHRP-6 induced a rise in intracellular Ca2+ in individual somatotrophs loaded with the Ca2+ indicator, Fura-2. Preincubation (3 min) with somatostatin (SRIF) diminished the Ca2+ spike elicited by GHRP-6, while no effect of SRIF was observed when added simultaneously with GHRP-6. These results indicate that GHRP-6-stimulated GH-secretion involves the diacylglycerol/inositol(1,4,5)trisphosphate pathway with a resulting rise in cytosolic Ca2+.

  15. Precedence relationship representations of mechanical assembly sequences

    NASA Technical Reports Server (NTRS)

    Homendemello, L. S.; Sanderson, A. C.

    1989-01-01

    Two types of precedence relationship representations for mechanical assembly sequences are presented: precedence relationships between the establishment of one connection between two parts and the establishment of another connection, and precedence relationships between the establishment of one connection and states of the assembly process. Precedence relationship representations have the advantage of being very compact. The problem with these representations was how to guarantee their correctness and completeness. Two theorems are presented each of which leads to the generation of one type of precedence relationship representation guaranteeing its correctness and completeness for a class of assemblies.

  16. Inositol phosphates influence the membrane bound Ca/sup 2 +//Mg/sup 2 +/ stimulated ATPase from human erythrocyte membranes

    SciTech Connect

    Kester, M.; Ekholm, J.; Kumar, R.; Hanahan, D.J.

    1986-03-01

    The modulation by exogenous inositol phosphates of the membrane Ca/sup 2 +//Mg/sup 2 +/ ATPase from saponin/EGTA lysed human erythrocytes was determined in a buffer (pH 7.6) containing histidine, 80 mM, MgCl/sub 2/, 3.3 mM, NaCl, 74 mM, KCl, 30 mM, Na/sub 2/ATP, 2.3 mM, ouabain, 0.83 mM, with variable amounts of CaCl/sub 2/ and EGTA. The ATPase assay was linear with time at 44/sup 0/C. The inositol phosphates were commercially obtained and were also prepared from /sup 32/P labeled rabbit platelet inositol phospholipids. Inositol triphosphate (IP/sub 3/) elevated the Ca/sup 2 +//Mg/sup 2 +/ ATPase activity over basal levels in a dose, time, and calcium dependent manner and were increased up to 85% of control values. Activities for the Na/sup +//K/sup +/-ATPase and a Mg/sup 2 +/ ATPase were not effected by IP/sub 3/. Ca/sup 2 +//Mg/sup 2 +/APTase activity with IP/sub 2/ or IP/sub 3/ could be synergistically elevated with calmodulin addition. The activation of the ATPase with IP/sub 3/ was calcium dependent in a range from .001 to .02 mM. The apparent Km and Vmax values were determined for IP/sub 3/ stimulated Ca/sup 2 +//Mg/sup 2 +/ ATPase.

  17. A role for rat inositol polyphosphate kinases rIPK2 and rIPK1 in inositol pentakisphosphate and inositol hexakisphosphate production in rat-1 cells.

    PubMed

    Fujii, Makoto; York, John D

    2005-01-14

    Over 30 inositol polyphosphates are known to exist in mammalian cells; however, the majority of them have uncharacterized functions. In this study we investigated the molecular basis of synthesis of highly phosphorylated inositol polyphosphates (such as inositol tetrakisphosphate, inositol pentakisphosphate (IP5), and inositol hexakisphosphate (IP6)) in rat cells. We report that heterologous expression of rat inositol polyphosphate kinases rIPK2, a dual specificity inositol trisphosphate/inositol tetrakisphosphate kinase, and rIPK1, an IP5 2-kinase, were sufficient to recapitulate IP6 synthesis from inositol 1,4,5-trisphosphate in mutant yeast cells. Overexpression of rIPK2 in Rat-1 cells increased inositol 1,3,4,5,6-pentakisphosphate (I(1,3,4,5,6)P5) levels about 2-3-fold compared with control. Likewise in Rat-1 cells, overexpression of rIPK1 was capable of completely converting I(1,3,4,5,6)P5 to IP6. Simultaneous overexpression of both rIPK2 and rIPK1 in Rat-1 cells increased both IP5 and IP6 levels. To reduce IPK2 activity in Rat-1 cells, we introduced vector-based short interference RNA against rIPK2. Cells harboring the short interference RNA had a 90% reduction of mRNA levels and a 75% decrease of I(1,3,4,5,6)P5. These data confirm the involvement of IPK2 and IPK1 in the conversion of inositol 1,4,5-trisphosphate to IP6 in rat cells. Furthermore these data suggest that rIPK2 and rIPK1 act as key determining steps in production of IP5 and IP6, respectively. The ability to modulate the intracellular inositol polyphosphate levels by altering IPK2 and IPK1 expression in rat cells will provide powerful tools to study the roles of I(1,3,4,5,6)P5 and IP6 in cell signaling.

  18. Saccharomyces cerevisiae mutant with a partial defect in the synthesis of CDP-diacylglycerol and altered regulation of phospholipid biosynthesis.

    PubMed Central

    Klig, L S; Homann, M J; Kohlwein, S D; Kelley, M J; Henry, S A; Carman, G M

    1988-01-01

    A Saccharomyces cerevisiae mutant (cdg1 mutation) was isolated on the basis of an inositol excretion phenotype and exhibited pleiotropic deficiencies in phospholipid biosynthesis. Genetic analysis of the mutant confirmed that the cdg1 mutation represents a new genetic locus and that a defect in a single gene was responsible for the Cdg1 phenotype. CDP-diacylglycerol synthase activity in mutant haploid cells was 25% of the wild-type derepressed level. Biochemical and immunoblot analyses revealed that the defect in CDP-diacylglycerol synthase activity in the cdg1 mutant was due to a reduced level of the CDP-diacylglycerol synthase Mr-56,000 subunit rather than to an alteration in the enzymological properties of the enzyme. This defect resulted in a reduced rate of CDP-diacylglycerol synthesis, an elevated phosphatidate content, and alterations in overall phospholipid synthesis. Unlike wild-type cells, CDP-diacylglycerol synthase was not regulated in response to water-soluble phospholipid precursors. The cdg1 lesion also caused constitutive expression of inositol-1-phosphate synthase and elevated phosphatidylserine synthase. Phosphatidylinositol synthase was not affected in the cdg1 mutant. Images PMID:2832385

  19. Inositol polyphosphate phosphatases in human disease.

    PubMed

    Hakim, Sandra; Bertucci, Micka C; Conduit, Sarah E; Vuong, David L; Mitchell, Christina A

    2012-01-01

    Phosphoinositide signalling molecules interact with a plethora of effector proteins to regulate cell proliferation and survival, vesicular trafficking, metabolism, actin dynamics and many other cellular functions. The generation of specific phosphoinositide species is achieved by the activity of phosphoinositide kinases and phosphatases, which phosphorylate and dephosphorylate, respectively, the inositol headgroup of phosphoinositide molecules. The phosphoinositide phosphatases can be classified as 3-, 4- and 5-phosphatases based on their specificity for dephosphorylating phosphates from specific positions on the inositol head group. The SAC phosphatases show less specificity for the position of the phosphate on the inositol ring. The phosphoinositide phosphatases regulate PI3K/Akt signalling, insulin signalling, endocytosis, vesicle trafficking, cell migration, proliferation and apoptosis. Mouse knockout models of several of the phosphoinositide phosphatases have revealed significant physiological roles for these enzymes, including the regulation of embryonic development, fertility, neurological function, the immune system and insulin sensitivity. Importantly, several phosphoinositide phosphatases have been directly associated with a range of human diseases. Genetic mutations in the 5-phosphatase INPP5E are causative of the ciliopathy syndromes Joubert and MORM, and mutations in the 5-phosphatase OCRL result in Lowe's syndrome and Dent 2 disease. Additionally, polymorphisms in the 5-phosphatase SHIP2 confer diabetes susceptibility in specific populations, whereas reduced protein expression of SHIP1 is reported in several human leukaemias. The 4-phosphatase, INPP4B, has recently been identified as a tumour suppressor in human breast and prostate cancer. Mutations in one SAC phosphatase, SAC3/FIG4, results in the degenerative neuropathy, Charcot-Marie-Tooth disease. Indeed, an understanding of the precise functions of phosphoinositide phosphatases is not only

  20. Targeting Phospholipid Metabolism in Cancer

    PubMed Central

    Cheng, Menglin; Bhujwalla, Zaver M.; Glunde, Kristine

    2016-01-01

    All cancers tested so far display abnormal choline and ethanolamine phospholipid metabolism, which has been detected with numerous magnetic resonance spectroscopy (MRS) approaches in cells, animal models of cancer, as well as the tumors of cancer patients. Since the discovery of this metabolic hallmark of cancer, many studies have been performed to elucidate the molecular origins of deregulated choline metabolism, to identify targets for cancer treatment, and to develop MRS approaches that detect choline and ethanolamine compounds for clinical use in diagnosis and treatment monitoring. Several enzymes in choline, and recently also ethanolamine, phospholipid metabolism have been identified, and their evaluation has shown that they are involved in carcinogenesis and tumor progression. Several already established enzymes as well as a number of emerging enzymes in phospholipid metabolism can be used as treatment targets for anticancer therapy, either alone or in combination with other chemotherapeutic approaches. This review summarizes the current knowledge of established and relatively novel targets in phospholipid metabolism of cancer, covering choline kinase α, phosphatidylcholine-specific phospholipase D1, phosphatidylcholine-specific phospholipase C, sphingomyelinases, choline transporters, glycerophosphodiesterases, phosphatidylethanolamine N-methyltransferase, and ethanolamine kinase. These enzymes are discussed in terms of their roles in oncogenic transformation, tumor progression, and crucial cancer cell properties such as fast proliferation, migration, and invasion. Their potential as treatment targets are evaluated based on the current literature. PMID:28083512

  1. Characterization of inositol phosphates in carrot (Daucus carota L. ) cells

    SciTech Connect

    Rincon, M.; Chen, Q.; Boss, W.F. )

    1989-01-01

    We have shown previously that inositol-1,4,5-trisphosphate (IP{sub 3}) stimulates an efflux of {sup 45}Ca{sup 2+} from fusogenic carrot protoplasts. In light of these results, we suggested that IP{sub 3} might serve as a second messenger for the mobilization of intracellular Ca{sup 2+} in higher plant cells. To determine whether or not IP{sub 3} and other inositol phosphates were present in the carrot cells, the cells were labeled with myo-(2-{sup 3}H)inositol for 18 hours and extracted with ice-cold 10% trichloroacetic acid. The inositol metabolites were separated by anion exchange chromatography and by paper electrophoresis. We found that ({sup 3}H)inositol metabolites coeluted with inositol bisphosphate (IP{sub 2}) and IP{sub 3} when separated by anion exchange chromatography. However, we could not detect IP{sub 2} or IP{sub 3} when the inositol metabolites were analyzed by paper electrophoresis even though the polyphosphoinositides, which are the source of IP{sub 2} and IP{sub 3}, were present in these cells. Thus, ({sup 3}H)inositol metabolites other than IP{sub 2} and IP{sub 3} had coeluted on the anion exchange columns. The data indicate that either IP{sub 3} is rapidly metabolized or that it is not present at a detectable level in the carrot cells.

  2. Adhesion to fibronectin stimulates inositol lipid synthesis and enhances PDGF-induced inositol lipid breakdown

    PubMed Central

    1993-01-01

    The aim of these experiments was to investigate whether inositol lipids might mediate some of the effects of extracellular matrix (ECM) on cellular form and functions. The lipid phosphatidylinositol bisphosphate (PIP2) plays a role in cytoskeletal regulation while its hydrolysis products, diacylglycerol and inositol triphosphate, serve as second messengers. We therefore measured the effect of adhesion to fibronectin (FN) on PIP2 and its hydrolysis products, in the presence and absence of the soluble mitogen PDGF. PDGF induced a threefold increase in release of water-soluble inositol phosphates in C3H 10T1/2 fibroblasts when cells were attached to FN, but had little effect in suspended cells. Suppression of inositol phosphate release in unattached cells was not due to dysfunction of the PDGF receptor or failure to activate phospholipase C-gamma; PDGF induced similar tyrosine phosphorylation of PLC-gamma under both conditions. By contrast, the total mass of phosphatidylinositol bisphosphate (PIP2), the substrate for PLC-gamma, was found to decrease by approximately 80% when cells were detached from their ECM attachments and placed in suspension in the absence of PDGF. PIP2 levels were restored when suspended cells were replated on FN, demonstrating that the effect was reversible. Furthermore, a dramatic increase in synthesis of PIP2 could be measured in cells within 2 min after reattachment to FN in the absence of PDGF. These results show that FN acts directly to stimulate PIP2 synthesis, and that it also enhances PIP2 hydrolysis in response to PDGF. The increase in PIP2 induced by adhesion may mediate some of the known effects of FN on cell shape and cytoskeletal organization, while regulation of inositol lipid hydrolysis may provide a means for integrating hormone- and ECM-dependent signaling pathways. PMID:8387531

  3. Functional Characterization of Pneumocystis carinii Inositol Transporter 1.

    PubMed

    Cushion, Melanie T; Collins, Margaret S; Sesterhenn, Thomas; Porollo, Aleksey; Vadukoot, Anish Kizhakkekkara; Merino, Edward J

    2016-12-13

    Fungi in the genus Pneumocystis live in the lungs of mammals, where they can cause a fatal pneumonia (PCP [Pneumocystis pneumonia]) in hosts with compromised immune systems. The absence of a continuous in vitro culture system for any species of Pneumocystis has led to limited understanding of these fungi, especially for the discovery of new therapies. We recently reported that Pneumocystis carinii, Pneumocystis murina, and most significantly, Pneumocystis jirovecii lack both enzymes necessary for myo-inositol biosynthesis but contain genes with homologies to fungal myo-inositol transporters. Since myo-inositol is essential for eukaryotic viability, the primary transporter, ITR1, was functionally and structurally characterized in P. carinii The predicted structure of P. carinii ITR1 (PcITR1) contained 12 transmembrane alpha-helices with intracellular C and N termini, consistent with other inositol transporters. The apparent Km was 0.94 ± 0.08 (mean ± standard deviation), suggesting that myo-inositol transport in P. carinii is likely through a low-affinity, highly selective transport system, as no other sugars or inositol stereoisomers were significant competitive inhibitors. Glucose transport was shown to use a different transport system. The myo-inositol transport was distinct from mammalian transporters, as it was not sodium dependent and was cytochalasin B resistant. Inositol transport in these fungi offers an attractive new drug target because of the reliance of the fungi on its transport, clear differences between the mammalian and fungal transporters, and the ability of the host to both synthesize and transport this critical nutrient, predicting low toxicity of potential inhibitors to the fungal transporter. myo-Inositol is a sugarlike nutrient that is essential for life in most organisms. Humans and microbes alike can obtain it by making it, which involves only 2 enzymes, by taking it from the environment by a transport process, or by recycling it from

  4. Myo-Inositol-Dependent Sodium Uptake in Ice Plant1

    PubMed Central

    Nelson, Donald E.; Koukoumanos, Michelle; Bohnert, Hans J.

    1999-01-01

    In salt-stressed ice plants (Mesembryanthemum crystallinum), sodium accumulates to high concentrations in vacuoles, and polyols (myo-inositol, d-ononitol, and d-pinitol) accumulate in the cytosol. Polyol synthesis is regulated by NaCl and involves induction and repression of gene expression (D.E. Nelson, B. Shen, and H.J. Bohnert [1998] Plant Cell 10: 753–764). In the study reported here we found increased phloem transport of myo-inositol and reciprocal increased transport of sodium and inositol to leaves under stress. To determine the relationship between increased translocation and sodium uptake, we analyzed the effects of exogenous application of myo-inositol: The NaCl-inducible ice plant myo-inositol 1-phosphate synthase is repressed in roots, and sodium uptake from root to shoot increases without stimulating growth. Sodium uptake and transport through the xylem was coupled to a 10-fold increase of myo-inositol and ononitol in the xylem. Seedlings of the ice plant are not salt-tolerant, and yet the addition of exogenous myo-inositol conferred upon them patterns of gene expression and polyol accumulation observed in mature, salt-tolerant plants. Sodium uptake and transport through the xylem was enhanced in the presence of myo-inositol. The results indicate an interdependence of sodium uptake and alterations in the distribution of myo-inositol. We hypothesize that myo-inositol could serve not only as a substrate for the production of compatible solutes but also as a leaf-to-root signal that promotes sodium uptake. PMID:9880357

  5. Inositol phosphate signaling and gibberellic acid

    PubMed Central

    Fleet, Christine M; Ercetin, Mustafa E

    2009-01-01

    To respond to physical signals and endogenous hormones, plants use specific signal transduction pathways. We and others have previously shown that second messenger inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] is used in abscisic acid (ABA) signaling, and that some mutants with altered Ins(1,4,5)P3 have altered responses to ABA. Specifically, mutants defective in the myo-inositol polyphosphate 5-phosphatases (5PTases) 1 and 2 genes that hydrolyze 5-phosphates from Ins(1,4,5)P3 and other PtdInsP and InsP substrates, have elevated Ins (1,4,5)P3, and are ABA-hypersensitive. Given the antagonistic relationship between ABA and gibberellic acid (GA), we tested the response of these same mutants to a GA synthesis inhibitor, paclobutrazol (PAC). We report here that 5ptase1, 5ptase2 and 5ptase11 mutants are hypersensitive to PAC, suggesting a relationship between elevated Ins(1,4,5)P3 and decreased GA signal transduction. These data provide insight into signaling cross-talk between ABA and GA pathways. PMID:19704714

  6. Inositol trisphosphate regulation of photoreceptor membrane currents.

    PubMed Central

    Sakakibara, M; Alkon, D L; Neary, J T; Heldman, E; Gould, R

    1986-01-01

    In previous studies elevation of intracellular Ca2+ was shown to cause prolonged reduction of two voltage-dependent K+ currents (IA and ICa2+-K+) across the membrane of the isolated Hermissenda photoreceptor, the type B cell (Alkon et al., 1982b; Alkon and Sakakibara, 1985). Here we show that iontophoretic injection of inositol trisphosphate (IP3), but not inositol monophosphate, also caused prolonged reduction of IA and ICa2+-K+. IP3 injection also caused reduction of a light-induced K+ current (also ICa2+-K+) but did not affect the voltage-dependent Ca2+ current, ICa2+, or the light-induced inward current, INa+, of the type B cell. IP3 injection caused similar effects on the K+ currents of the other type of Hermissenda photoreceptor, the type A cell. INA+ of the type A cell, unlike that of the type B cell, was, however, markedly increased following IP3 injection. The differences of IP3 effects on the two types of photoreceptors may be related to differences in regulation of ionic currents by endogenous IP3 as reflected by clear differences (before injection) in the magnitude of IA, ICa2+-K+, and INa+ between the two cell types. PMID:3491632

  7. Inositol pyrophosphates: why so many phosphates?

    PubMed Central

    Shears, Stephen B.

    2014-01-01

    The inositol pyrophosphates (PP-InsPs) are a specialized group of “energetic” signaling molecules found in yeasts, plants and animals. PP-InsPs boast the most crowded three dimensional phosphate arrays found in Nature; multiple phosphates and diphosphates are crammed around the six-carbon, inositol ring. Yet, phosphate esters are also a major energy currency in cells. So the synthesis of PP-InsPs, and the maintenance of their levels in the face of a high rate of ongoing turnover, all requires significant bioenergetic input. What are the particular properties of PP-InsPs that repay this investment of cellular energy? Potential answers to that question are discussed here, against the backdrop of a recent hypothesis that signaling by PP-InsPs is evolutionarily ancient. The latter idea is extended herein, with the proposal that the primordial origins of PP-InsPs is reflected in the apparent lack of isomeric specificity of certain of their actions. Nevertheless, there are other aspects of signaling by these polyphosphates that are more selective for a particular PP-InsP isomer. Consideration of the nature of both specific and non-specific effects of PP-InsPs can help rationalize why such molecules possess so many phosphates. PMID:25453220

  8. [Coupled excitation and contraction in skeletal muscles: arguments in favor of a mechanism implicating inositol metabolism].

    PubMed

    Potus, J

    1986-01-01

    When mouse diaphragms are incubated in vitro with [14C] inositol, radioactivity is observed at post synaptic areas in phosphatidyl-inositols and in inositol-phosphates. Synaptic desensitization suppresses the labelled inositol-phosphates. Lindane restores the labelling effect without suppressing the desensitized state.

  9. Nanomechanics of electrospun phospholipid fiber

    NASA Astrophysics Data System (ADS)

    Mendes, Ana C.; Nikogeorgos, Nikolaos; Lee, Seunghwan; Chronakis, Ioannis S.

    2015-06-01

    Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 ± 2.7 μm. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 ± 1 MPa. At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip. The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h.

  10. Nanomechanics of electrospun phospholipid fiber

    SciTech Connect

    Mendes, Ana C. E-mail: ioach@food.dtu.dk; Chronakis, Ioannis S. E-mail: ioach@food.dtu.dk; Nikogeorgos, Nikolaos; Lee, Seunghwan

    2015-06-01

    Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 ± 2.7 μm. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 ± 1 MPa. At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip. The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h.

  11. Phosphoinositide and Inositol Phosphate Analysis in Lymphocyte Activation

    PubMed Central

    Sauer, Karsten; Huang, Yina Hsing; Lin, Hongying; Sandberg, Mark; Mayr, Georg W.

    2015-01-01

    Lymphocyte antigen receptor engagement profoundly changes the cellular content of phosphoinositide lipids and soluble inositol phosphates. Among these, the phosphoinositides phosphatidylinositol 4,5-bisphosphate (PIP2) and phosphatidylinositol 3,4,5-trisphosphate (PIP3) play key signaling roles by acting as pleckstrin homology (PH) domain ligands that recruit signaling proteins to the plasma membrane. Moreover, PIP2 acts as a precursor for the second messenger molecules diacylglycerol and soluble inositol 1,4,5-trisphosphate (IP3), essential mediators of PKC, Ras/Erk, and Ca2+ signaling in lymphocytes. IP3 phosphorylation by IP3 3-kinases generates inositol 1,3,4,5-tetrakisphosphate (IP4), an essential soluble regulator of PH domain binding to PIP3 in developing T cells. Besides PIP2, PIP3, IP3, and IP4, lymphocytes produce multiple other phosphoinositides and soluble inositol phosphates that could have important physiological functions. To aid their analysis, detailed protocols that allow one to simultaneously measure the levels of multiple different phosphoinositide or inositol phosphate isomers in lymphocytes are provided here. They are based on thin layer, conventional and high-performance liquid chromatographic separation methods followed by radiolabeling or non-radioactive metal-dye detection. Finally, less broadly applicable nonchromatographic methods for detection of specific phosphoinositide or inositol phosphate isomers are discussed. Support protocols describe how to obtain pure unstimulated CD4+CD8+ thymocyte populations for analyses of inositol phosphate turnover during positive and negative selection, key steps in T cell development. PMID:19918943

  12. Myo-inositol in the treatment of premenstrual dysphoric disorder.

    PubMed

    Gianfranco, Carlomagno; Vittorio, Unfer; Silvia, Buffo; Francesco, D'Ambrosio

    2011-10-01

    Premenstrual dysphoric disorder (PMDD) is a mood disorder disrupting social and/or occupational life of affected women. Premenstrual dysphoric disorder etiology is unknown, although a pivotal role is played by the serotoninergic system. Indeed, one of the most effective treatments is selective serotonin reuptake inhibitors. Several studies have proposed a selective serotonin reuptake inhibitor-like role for myo-inositol, likely due to the fact that myo-inositol is the second messenger of serotonin. In the present study, we aimed to investigate the effect of myo-inositol in the treatment of PMDD. We used a two-phase clinical trial approach (phase I: placebo washout; phase II: comparisons between treatment and placebo) and treated PMMD patients with two different myo-inositol formulations: powder or soft gel capsules. We decided to test these two formulations because according to the manufacturer, 0.6 g of myo-inositol in soft gel capsule has a pharmacokinetic equivalent to 2 g of myo-inositol in powder. Our results showed a significant improvement of three different scales: a reduction in the Daily Symptoms Records scale and an improvement of the Hamilton Depression Rating and Clinical Global Impression-Severity of Illness scales. Results were similar for both formulations. In the present study, by using a new pharmaceutical formulation, we were able to clearly prove the efficacy of myo-inositol in PMDD. Copyright © 2011 John Wiley & Sons, Ltd.

  13. scyllo-Inositol promotes robust mutant Huntingtin protein degradation.

    PubMed

    Lai, Aaron Y; Lan, Cynthia P; Hasan, Salwa; Brown, Mary E; McLaurin, Joanne

    2014-02-07

    Huntington disease is characterized by neuronal aggregates and inclusions containing polyglutamine-expanded huntingtin protein and peptide fragments (polyQ-Htt). We have used an established cell-based assay employing a PC12 cell line overexpressing truncated exon 1 of Htt with a 103-residue polyQ expansion that yields polyQ-Htt aggregates to investigate the fate of polyQ-Htt-drug complexes. scyllo-Inositol is an endogenous inositol stereoisomer known to inhibit accumulation and toxicity of the amyloid-β peptide and α-synuclein. In light of these properties, we investigated the effect of scyllo-inositol on polyQ-Htt accumulation. We show that scyllo-inositol lowered the number of visible polyQ-Htt aggregates and robustly decreased polyQ-Htt protein abundance without concomitant cellular toxicity. We found that scyllo-inositol-induced polyQ-Htt reduction was by rescue of degradation pathways mediated by the lysosome and by the proteasome but not autophagosomes. The rescue of degradation pathways was not a direct result of scyllo-inositol on the lysosome or proteasome but due to scyllo-inositol-induced reduction in mutant polyQ-Htt protein levels.

  14. A Novel Inositol Pyrophosphate Phosphatase in Saccharomyces cerevisiae

    PubMed Central

    Steidle, Elizabeth A.; Chong, Lucy S.; Wu, Mingxuan; Crooke, Elliott; Fiedler, Dorothea; Resnick, Adam C.; Rolfes, Ronda J.

    2016-01-01

    Inositol pyrophosphates are high energy signaling molecules involved in cellular processes, such as energetic metabolism, telomere maintenance, stress responses, and vesicle trafficking, and can mediate protein phosphorylation. Although the inositol kinases underlying inositol pyrophosphate biosynthesis are well characterized, the phosphatases that selectively regulate their cellular pools are not fully described. The diphosphoinositol phosphate phosphohydrolase enzymes of the Nudix protein family have been demonstrated to dephosphorylate inositol pyrophosphates; however, the Saccharomyces cerevisiae homolog Ddp1 prefers inorganic polyphosphate over inositol pyrophosphates. We identified a novel phosphatase of the recently discovered atypical dual specificity phosphatase family as a physiological inositol pyrophosphate phosphatase. Purified recombinant Siw14 hydrolyzes the β-phosphate from 5-diphosphoinositol pentakisphosphate (5PP-IP5 or IP7) in vitro. In vivo, siw14Δ yeast mutants possess increased IP7 levels, whereas heterologous SIW14 overexpression eliminates IP7 from cells. IP7 levels increased proportionately when siw14Δ was combined with ddp1Δ or vip1Δ, indicating independent activity by the enzymes encoded by these genes. We conclude that Siw14 is a physiological phosphatase that modulates inositol pyrophosphate metabolism by dephosphorylating the IP7 isoform 5PP-IP5 to IP6. PMID:26828065

  15. Biosynthesis and possible functions of inositol pyrophosphates in plants

    PubMed Central

    Williams, Sarah P.; Gillaspy, Glenda E.; Perera, Imara Y.

    2015-01-01

    Inositol phosphates (InsPs) are intricately tied to lipid signaling, as at least one portion of the inositol phosphate signaling pool is derived from hydrolysis of the lipid precursor, phosphatidyl inositol (4,5) bisphosphate. The focus of this review is on the inositol pyrophosphates, which are a novel group of InsP signaling molecules containing diphosphate or triphosphate chains (i.e., PPx) attached to the inositol ring. These PPx-InsPs are emerging as critical players in the integration of cellular metabolism and stress signaling in non-plant eukaryotes. Most eukaryotes synthesize the precursor molecule, myo-inositol (1,2,3,4,5,6)-hexakisphosphate (InsP6), which can serve as a signaling molecule or as storage compound of inositol, phosphorus, and minerals (referred to as phytic acid). Even though plants produce huge amounts of precursor InsP6 in seeds, almost no attention has been paid to whether PPx-InsPs exist in plants, and if so, what roles these molecules play. Recent work has delineated that Arabidopsis has two genes capable of PP-InsP5 synthesis, and PPx-InsPs have been detected across the plant kingdom. This review will detail the known roles of PPx-InsPs in yeast and animal systems, and provide a description of recent data on the synthesis and accumulation of these novel molecules in plants, and potential roles in signaling. PMID:25729385

  16. Interactions of Amelogenin with Phospholipids

    PubMed Central

    Lokappa, Sowmya Bekshe; Chandrababu, Karthik Balakrishna; Dutta, Kaushik; Perovic, Iva; Evans, John Spencer; Moradian-Oldak, Janet

    2015-01-01

    Amelogenin protein has the potential to interact with other enamel matrix proteins, mineral and cell surfaces. We investigated the interactions of recombinant amelogenin rP172 with small unilamellar vesicles as model membranes, towards the goal of understanding the mechanisms of amelogenin-cell interactions during amelogenesis. Dynamic light scattering (DLS), fluorescence spectroscopy, circular dichroism (CD) and nuclear magnetic resonance (NMR) were used. In the presence of phospholipid vesicles, a blue shift in the Trp fluorescence emission maxima of rP172 was observed (~334 nm) and the Trp residues of rP172 were inaccessible to the aqueous quencher acrylamide. Though in DLS studies we cannot exclude the possibility of fusion of liposomes as the result of amelogenin addition, NMR and CD studies revealed a disorder-order transition of rP172 in a model membrane environment. Strong FRET from Trp in rP172 to DNS–bound-phospholipid was observed, and fluorescence polarization studies indicated that rP172 interacted with the hydrophobic core region of model membranes. Our data suggest that amelogenin has ability to interact with phospholipids and that such interactions may play key roles in enamel biomineralization as well as reported amelogenin signaling activities. PMID:25298002

  17. Nutritional Deficiencies and Phospholipid Metabolism

    PubMed Central

    Gimenez, María S.; Oliveros, Liliana B.; Gomez, Nidia N.

    2011-01-01

    Phospholipids are important components of the cell membranes of all living species. They contribute to the physicochemical properties of the membrane and thus influence the conformation and function of membrane-bound proteins, such as receptors, ion channels, and transporters and also influence cell function by serving as precursors for prostaglandins and other signaling molecules and modulating gene expression through the transcription activation. The components of the diet are determinant for cell functionality. In this review, the effects of macro and micronutrients deficiency on the quality, quantity and metabolism of different phospholipids and their distribution in cells of different organs is presented. Alterations in the amount of both saturated and polyunsaturated fatty acids, vitamins A, E and folate, and other micronutrients, such as zinc and magnesium, are discussed. In all cases we observe alterations in the pattern of phospholipids, the more affected ones being phosphatidylcholine, phosphatidylethanolamine and sphingomyelin. The deficiency of certain nutrients, such as essential fatty acids, fat-soluble vitamins and some metals may contribute to a variety of diseases that can be irreversible even after replacement with normal amount of the nutrients. Usually, the sequelae are more important when the deficiency is present at an early age. PMID:21731449

  18. Inositol-deficient food augments a behavioral effect of long-term lithium treatment mediated by inositol monophosphatase inhibition: an animal model with relevance for bipolar disorder.

    PubMed

    Shtein, Liza; Agam, Galila; Belmaker, R H; Bersudsky, Yuly

    2015-04-01

    Lithium treatment in rodents markedly enhances cholinergic agonists such as pilocarpine. This effect can be reversed in a stereospecific manner by administration of inositol, suggesting that the effect of lithium is caused by inositol monophosphatase inhibition and consequent inositol depletion. If so, inositol-deficient food would be expected to enhance lithium effects. Inositol-deficient food was prepared from inositol-free ingredients. Mice with a homozygote knockout of the inositol monophosphatase 1 gene unable to synthesize inositol endogenously and mimicking lithium-treated animals were fed this diet or a control diet. Lithium-treated wild-type animals were also treated with the inositol-deficient diet or control diet. Pilocarpine was administered after 1 week of treatment, and behavior including seizures was assessed using rating scale. Inositol-deficient food-treated animals, both lithium treated and with inositol monophosphatase 1 knockout, had significantly elevated cholinergic behavior rating and significantly increased or earlier seizures compared with the controls. The effect of inositol-deficient food supports the role of inositol depletion in the effects of lithium on pilocarpine-induced behavior. However, the relevance of this behavior to other more mood-related effects of lithium is not clear.

  19. [Phospholipids and structural modification of tissues and cell membranes for adaptation in high altitude mountains].

    PubMed

    Iakovlev, V M; Vishnevskiĭ, A A; Shanazarov, A S

    2012-01-01

    The nature of the impact of physical factors of high altitudes (3200 m) on the lipids of tissues and membranes of animals was researched. It was established that the adaptation process in Wistar rats was followed by peroxide degradation and subsequent modification of the phospholipids' structure of tissues and microsomal membranes. Adaptive phospholipids reconstruction takes place in microsomal membranes in the tissues of the lungs, brain, liver and skeletal muscles. Together with this, the amount of phosphatidylinositol and phosphatidic acid accumulates, indicating that the hydrolysis of phosphatidylinositol-4, 5 biphosphate to diacylglycerol and secondary messenger--inositol triphosphate, occurs. A decrease in temperature adaptation (+10 degrees C) leads to a more noticeable shift in peroxide oxidation of lipids, phospholipid structure in the tissues and membranes rather than adaptation in thermoneutral conditions (+30 degrees C). Modification of lipid composition of tissues and cell membranes in the highlands obviously increases the adaptive capabilities of cells of the whole body: physical performance and resistance to hypoxia increases in animals.

  20. myo-Inositol homeostasis in foetal rabbit lung

    PubMed Central

    Bleasdale, John E.; Maberry, Mark C.; Quirk, J. Gerald

    1982-01-01

    In several species, lung maturation is accompanied by a decline in the phosphatidylinositol content of lung surfactant and a concomitant increase in its phosphatidylglycerol content. To examine the possibility that this developmental change is influenced by the availability of myo-inositol, potential sources of myo-inositol for the developing rabbit lung were investigated. On day 28 of gestation the myo-inositol content of foetal rabbit lung tissue (2.3±0.5μmol/g of tissue) was not significantly different from that of adult lung tissue but the activity of d-glucose 6-phosphate:1l-myo-inositol 1-phosphate cyclase (cyclase) in foetal lung tissue (81.0±9.0nmol·h−1·g of tissue−1) was higher than that found in adult lung tissue (23.2±1.0nmol·h−1·g of tissue−1). Day 28 foetal rabbit lung tissue was found also to take up myo-inositol by a specific, energy-dependent, Na+-requiring mechanism. Half-maximal uptake of myo-inositol by foetal rabbit lung slices was observed when the concentration of myo-inositol in the incubation medium was 85μm. When the myo-inositol concentration was 1mm (but not 100μm) the addition of glucose (5.5mm) stimulated myo-inositol uptake. myo-Inositol uptake was observed also in adult rabbit lung and was found to be sub-maximal at the concentration of myo-inositol found in adult rabbit serum. The concentration of myo-inositol in the serum of pregnant adult rabbits (47.5±5.5μm) was significantly lower than that of non-pregnant adult female rabbits (77.9±9.2μm). On day 28 of gestation the concentration of myo-inositol in foetal serum (175.1±12.0μm) was much less than on day 25, but more than that found on day 30. A transient post-partum increase in the concentration of myo-inositol in serum was followed by a rapid decline. Much of the myo-inositol in foetal rabbit serum probably originates from the placenta, where on day 28 of gestation a high cyclase activity (527±64nmol·h−1·g of tissue−1) was measured. The gestational

  1. Beryllium competitively inhibits brain myo-inositol monophosphatase, but unlike lithium does not enhance agonist-induced inositol phosphate accumulation.

    PubMed Central

    Faraci, W S; Zorn, S H; Bakker, A V; Jackson, E; Pratt, K

    1993-01-01

    Despite limiting side-effects, lithium is the drug of choice for the treatment of bipolar depression. Its action may be due, in part, to its ability to dampen phosphatidylinositol turnover by inhibiting myo-inositol monophosphatase. Beryllium has been identified as a potent inhibitor of partially purified myo-inositol monophosphatase isolated from rat brain (Ki = 150 nM), bovine brain (Ki = 35 nM), and from the human neuroblastoma cell line SK-N-SH (Ki = 85 nM). It is over three orders of magnitude more potent than LiCl (Ki = 0.5-1.2 mM). Kinetic analysis reveals that beryllium is a competitive inhibitor of myo-inositol monophosphatase, in contrast with lithium which is an uncompetitive inhibitor. Inhibition of exogenous [3H]inositol phosphate hydrolysis by beryllium (IC50 = 250-300 nM) was observed to the same maximal extent as that seen with lithium in permeabilized SK-N-SH cells, reflecting inhibition of cellular myo-inositol monophosphatase. However, in contrast with that observed with lithium, agonist-induced accumulation of inositol phosphate was not observed with beryllium in permeabilized and non-permeabilized SK-N-SH cells and in rat brain slices. Similar results were obtained in permeabilized SK-N-SH cells when GTP-gamma-S was used as an alternative stimulator of inositol phosphate accumulation. The disparity in the actions of beryllium and lithium suggest that either (1) selective inhibition of myo-inositol monophosphatase does not completely explain the action of lithium on the phosphatidylinositol cycle, or (2) that uncompetitive inhibition of myo-inositol monophosphatase is a necessary requirement to observe functional lithium mimetic activity. PMID:8387266

  2. Inositol Hexaphosphate Inhibits Tumor Growth, Vascularity, and Metabolism in TRAMP Mice: A Multiparametric Magnetic Resonance Study

    PubMed Central

    Raina, Komal; Ravichandran, Kameswaran; Rajamanickam, Subapriya; Huber, Kendra M.; Serkova, Natalie. J.; Agarwal, Rajesh

    2012-01-01

    Herein, employing anatomical and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), we evaluated non-invasively, the in vivo, chemopreventive efficacy of inositol hexaphosphate (IP6), a major constituent of high fiber diets, against prostate tumor growth and progression in transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Male TRAMP mice, beginning 4 weeks of age, were fed with 1, 2 or 4% (w/v) IP6 in drinking water or only drinking water till 28 weeks of age and monitored using MRI over the course of study. Longitudinal assessment of prostate volumes by conventional MRI and tumor vascularity by gadolinium-based DCE-MRI showed a profound reduction in tumor size partly due to anti-angiogenic effects by IP6 treatment. As potential mechanisms of IP6 efficacy, decrease in the expression of glucose transporter GLUT-4 protein together with an increase in levels of phospho-AMP-activated kinase (AMPKTh172) were observed in prostate tissues of mice from IP6 fed-groups, suggesting that IP6 is interfering with the metabolic events occurring in TRAMP prostate. Investigative metabolomics study utilizing quantitative high-resolution 1H-NMR on prostate tissue extracts showed that IP6 significantly decreased glucose metabolism and membrane phospholipid synthesis, in addition to causing an increase in myo-inositol levels in the prostate. Together, these findings show that oral IP6 supplement blocks PCa growth and angiogenesis in TRAMP model in conjunction with metabolic events involved in tumor sustenance. This results in energy deprivation within the tumor, suggesting a practical and translational potential of IP6 treatment in suppressing growth and progression of prostate cancer in humans. PMID:23213071

  3. Phospholipids as Biomarkers for Excessive Alcohol Use

    DTIC Science & Technology

    2016-10-01

    is designed to evaluate the utility of levels of two phospholipids in serum as a marker of past drinking behavior across month - level time horizons...panel of serum phospholipids (sphingomyelin, and lysophosphatidylcholines) in proportion to the level of consumption in the past month . Further, we...the relationship between the panel of serum phospholipids of interest and the amount of alcohol consumption during the past month in returning

  4. A conserved family of enzymes that phosphorylate inositol hexakisphosphate.

    PubMed

    Mulugu, Sashidhar; Bai, Wenli; Fridy, Peter C; Bastidas, Robert J; Otto, James C; Dollins, D Eric; Haystead, Timothy A; Ribeiro, Anthony A; York, John D

    2007-04-06

    Inositol pyrophosphates are a diverse group of high-energy signaling molecules whose cellular roles remain an active area of study. We report a previously uncharacterized class of inositol pyrophosphate synthase and find it is identical to yeast Vip1 and Asp1 proteins, regulators of actin-related protein-2/3 (ARP 2/3) complexes. Vip1 and Asp1 acted as enzymes that encode inositol hexakisphosphate (IP6) and inositol heptakisphosphate (IP7) kinase activities. Alterations in kinase activity led to defects in cell growth, morphology, and interactions with ARP complex members. The functionality of Asp1 and Vip1 may provide cells with increased signaling capacity through metabolism of IP6.

  5. Absence of detectable inositol hexakisphosphate (phytate) in plasma.

    PubMed

    Irvine, Robin F

    2014-06-01

    A critical evaluation of a recent attempt to measure inositol hexakisphosphate (IP6) in mammalian plasma by mass spectroscopy leads to the conclusion that as yet there is no unambiguous evidence that plasma contains any IP6.

  6. Structural analysis of a multifunctional, tandemly repeated inositol polyphosphatase.

    PubMed

    Gruninger, Robert J; Selinger, L Brent; Mosimann, Steven C

    2009-09-11

    Mitsuokella multacida expresses a unique inositol polyphosphatase (PhyAmm) that is composed of tandem repeats (TRs). Each repeat possesses a protein tyrosine phosphatase (PTP) active-site signature sequence and fold. Using a combination of structural, mutational, and kinetic studies, we show that the N-terminal (D1) and C-terminal (D2) active sites of the TR have diverged and possess significantly different specificities for inositol polyphosphate. Structural analysis and molecular docking calculations identify steric and electrostatic differences within the substrate binding pocket of each TR that may be involved in the altered substrate specificity. The implications of our results for the biological function of related PTP-like phytases are discussed. Finally, the structures and activities of PhyAmm and tandemly repeated receptor PTPs are compared and discussed. To our knowledge, this is the first example of an inositol phosphatase with tandem PTP domains possessing substrate specificity for different inositol phosphates.

  7. Inositol and In Vitro Fertilization with Embryo Transfer

    PubMed Central

    Simi, G.; Genazzani, A. R.; Obino, M. E. R.; Papini, F.; Pinelli, S.; Cela, V.

    2017-01-01

    Recently, studies on inositol supplementation during in vitro fertilization program (IVF) have gained particular importance due to the effect of this molecule on reducing insulin resistance improving ovarian function, oocyte quality, and embryo and pregnancy rates and reducing gonadotropin amount during stimulation. Inositol and its isoforms, especially myoinositol (MYO), are often used as prestimulation therapy in infertile patients undergoing IVF cycle. Inositol supplementation started three months before ovarian stimulation, resulting in significant improvements in hormonal responses, reducing the amount of FSH necessary for optimal follicle development and serum levels of 17beta-estradiol measured the day of hCG injection. As shown by growing number of trials, MYO supplementation improves oocyte quality by reducing the number of degenerated and immature oocytes, in this way increasing the quality of embryos produced. Inositol can also improve the quality of sperm parameters in those patients affected by oligoasthenoteratozoospermia. PMID:28348586

  8. Phospholipid synthesis and transport in mammalian cells.

    PubMed

    Vance, Jean E

    2015-01-01

    Membranes of mammalian subcellular organelles contain defined amounts of specific phospholipids that are required for normal functioning of proteins in the membrane. Despite the wide distribution of most phospholipid classes throughout organelle membranes, the site of synthesis of each phospholipid class is usually restricted to one organelle, commonly the endoplasmic reticulum (ER). Thus, phospholipids must be transported from their sites of synthesis to the membranes of other organelles. In this article, pathways and subcellular sites of phospholipid synthesis in mammalian cells are summarized. A single, unifying mechanism does not explain the inter-organelle transport of all phospholipids. Thus, mechanisms of phospholipid transport between organelles of mammalian cells via spontaneous membrane diffusion, via cytosolic phospholipid transfer proteins, via vesicles and via membrane contact sites are discussed. As an example of the latter mechanism, phosphatidylserine (PS) is synthesized on a region of the ER (mitochondria-associated membranes, MAM) and decarboxylated to phosphatidylethanolamine in mitochondria. Some evidence is presented suggesting that PS import into mitochondria occurs via membrane contact sites between MAM and mitochondria. Recent studies suggest that protein complexes can form tethers that link two types of organelles thereby promoting lipid transfer. However, many questions remain about mechanisms of inter-organelle phospholipid transport in mammalian cells. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Oxidized Phospholipids: Biomarker for Cardiovascular Diseases

    PubMed Central

    Ashraf, Mohammad Z.; Kar, Niladri S.; Podrez, Eugene A.

    2009-01-01

    Biologically active oxidized phospholipids can initiate and modulate many of the cellular events attributed to inflammation leading to atherosclerosis. Produced by enzymatic or non-enzymatic processes, these molecules interact with various cells via specific receptors and in general give rise to inflammatory signals. There is considerable evidence that oxidized phospholipids accumulate in vivo and play significant roles in atherosclerosis and thrombosis, suggesting that oxidized phospholipids could be biomarkers that reflect the global extent of these diseases in vivo. Thus, understanding the biosynthetic pathways, receptor specificity and signaling processes of oxidized phospholipids is important in understanding atherosclerosis, thrombosis and related inflammatory diseases. PMID:19061967

  10. Functional Characterization of Pneumocystis carinii Inositol Transporter 1

    PubMed Central

    Collins, Margaret S.; Sesterhenn, Thomas; Porollo, Aleksey; Vadukoot, Anish Kizhakkekkara; Merino, Edward J.

    2016-01-01

    ABSTRACT Fungi in the genus Pneumocystis live in the lungs of mammals, where they can cause a fatal pneumonia (PCP [Pneumocystis pneumonia]) in hosts with compromised immune systems. The absence of a continuous in vitro culture system for any species of Pneumocystis has led to limited understanding of these fungi, especially for the discovery of new therapies. We recently reported that Pneumocystis carinii, Pneumocystis murina, and most significantly, Pneumocystis jirovecii lack both enzymes necessary for myo-inositol biosynthesis but contain genes with homologies to fungal myo-inositol transporters. Since myo-inositol is essential for eukaryotic viability, the primary transporter, ITR1, was functionally and structurally characterized in P. carinii. The predicted structure of P. carinii ITR1 (PcITR1) contained 12 transmembrane alpha-helices with intracellular C and N termini, consistent with other inositol transporters. The apparent Km was 0.94 ± 0.08 (mean ± standard deviation), suggesting that myo-inositol transport in P. carinii is likely through a low-affinity, highly selective transport system, as no other sugars or inositol stereoisomers were significant competitive inhibitors. Glucose transport was shown to use a different transport system. The myo-inositol transport was distinct from mammalian transporters, as it was not sodium dependent and was cytochalasin B resistant. Inositol transport in these fungi offers an attractive new drug target because of the reliance of the fungi on its transport, clear differences between the mammalian and fungal transporters, and the ability of the host to both synthesize and transport this critical nutrient, predicting low toxicity of potential inhibitors to the fungal transporter. PMID:27965450

  11. The inhibition of phosphoinositide synthesis and muscarinic-receptor-mediated phospholipase C activity by Li+ as secondary, selective, consequences of inositol depletion in 1321N1 cells.

    PubMed Central

    Batty, I H; Downes, C P

    1994-01-01

    Conditions are described for culture of 1321N1 cells under which cellular inositol is decreased from approximately 20 mM to < 0.5 mM but phosphoinositide concentrations are unaffected. The effects of the muscarinic-receptor agonist carbachol (1 mM) and/or LiCl (10 mM) on phosphoinositide turnover in these or in inositol-replete cells was examined after steady-state [3H]inositol labelling of phospholipid pools. In both inositol-replete and -depleted cells, carbachol stimulated similar initial (0-15 min) rates of phospholipase C (PLC) activity, in the presence of Li+. Subsequently (> 30-60 min) stimulated PLC activity and [3H]PtdIns concentrations declined dramatically only in depleted cells. In inositol-depleted cells, carbachol alone evoked increased concentrations of [3H]inositol, [3H]InsP1, [3H]InsP2, [3H]InsP3 and [3H]InsP4, which were largely sustained over 90 min, and concentrations of [3H]PtdIns, [3H]PtdInsP and [3H]PtdInsP2 were decreased only to approximately 82, 84 and 93% of control respectively. In the presence of Li+ in these cells, the stimulated rise in [3H]inositol was prevented and, although accumulation of [3H]InsP1, [3H]InsP2 and [3H]InsP3 was initially (0-30 min) potentiated, rates of accumulation of [3H]InsP1 and concentrations of [3H]polyphosphates later (> 30-60 min) declined, and concentrations of [3H]PtdIns, [3H]PtdInsP and [3H]PtdInsP2 were decreased respectively to approximately 39, 48 and 81% of control. After 60 min in the presence of both carbachol and Li+, stimulated PLC activity was decreased by approximately 70% compared with the initial rate in depleted cells. This decreased PLC activity was reflected by changes in the stimulated concentrations of [3H]Ins(1,3,4)P3 but not of [3H]Ins(1,4,5)P3, but effects of Li+ on the latter may have been obscured by the demonstrated, concomitant and equal stimulated accumulation of [3H]inositol 1:2cyclic,4,5-trisphosphate. These data suggest that receptor-mediated PLC activity is selectively

  12. Redistribution of tritium during germination of grain harvested from myo-(2-/sup 3/H)inositol- and scyllo-(R-/sup 3/H)inositol-labeled wheat

    SciTech Connect

    Sasaki, K.; Loewus, F.A.

    1982-01-01

    Wheat kernels from myo-(2-/sup 3/H)inositol- or scyllo-(R-/sup 3/H)inositol-labeled plants (Sasaki and Loewus 1980 Plant Physiol 66: 740-745) were used to study redistribution of /sup 3/H into growing regions during germination. Most of the labeled 1-..cap alpha..-galactinol (or the analogous scyllo-inositol galatoside) was hydrolyzed within 1 day. Water-soluble phytate was dephosphorylated within 3 days. A large reserve of bound phytate continued to release myo-inositol over several days. Translocation of free myo-inositol to growing regions provided substrate for the myo-inositol oxidation pathway and incorporation of /sup 3/H into new cell wall polysaccharides. Cell wall polysaccharides in the kernel were degraded during germination. The labeled residues were translocated to growing regions and reutilized for new cell wall formation. Pentosyl residues accounted for most of this label. Free scyllo-inositol followed a path of translocation from kernal to seeding similar to that of myo-inositol. Unlike myo-inositol, it did not furnish substrate for the myo-inositol oxidation pathway but accumulated as free scyllo-inositol in the seeding. The fate of phytate-derived myo-inositol during germination of wheat is discussed in relation to a recent scheme of phytate metabolism proposed by De and Biswas (1979 J Biol Chem 254 :8717-8719) for germinating mung bean seedlings.

  13. Listeria monocytogenes meningitis preceded by acute cholangitis.

    PubMed

    Luthe, Sarah Kyuragi; Sato, Ryota; Maeda, Tetsuro; Takahashi, Kuniko

    2017-03-20

    Listeria monocytogenes is a well-known cause of meningitis in immunocompromised patients. This organism has a growing significance for community-acquired meningitis, which should have ampicillin added to the usual regimen. We describe a case of L. monocytogenes meningitis preceded by cholangitis. This case suggests gastrointestinal symptoms preceding meningitis may be a clue of listeriosis. It is important for physicians to consider L. monocytogenes as a cause of bacterial meningitis in patients with altered mental status preceded by gastrointestinal symptoms, especially in the immunocompromised population.

  14. Synaptotagmin 1 causes phosphatidyl inositol lipid-dependent actin remodeling in cultured non-neuronal and neuronal cells

    SciTech Connect

    Johnsson, Anna-Karin; Karlsson, Roger

    2012-01-15

    Here we demonstrate that a dramatic actin polymerizing activity caused by ectopic expression of the synaptic vesicle protein synaptotagmin 1 that results in extensive filopodia formation is due to the presence of a lysine rich sequence motif immediately at the cytoplasmic side of the transmembrane domain of the protein. This polybasic sequence interacts with anionic phospholipids in vitro, and, consequently, the actin remodeling caused by this sequence is interfered with by expression of a phosphatidyl inositol (4,5)-bisphosphate (PIP2)-targeted phosphatase, suggesting that it intervenes with the function of PIP2-binding actin control proteins. The activity drastically alters the behavior of a range of cultured cells including the neuroblastoma cell line SH-SY5Y and primary cortical mouse neurons, and, since the sequence is conserved also in synaptotagmin 2, it may reflect an important fine-tuning role for these two proteins during synaptic vesicle fusion and neurotransmitter release.

  15. Enzymic synthesis of indol-3-ylacetyl-myo-inositol galactoside.

    PubMed

    Corcuera, L J; Michalczuk, L; Bandurski, R S

    1982-11-01

    Extracts of immature kernels of Zea mays catalysed the synthesis of indol-3-ylacetyl-myo-inositol galactoside from indol-3-ylacetyl-myo-inositol and UDP-galactose. Addition of 2-mercaptoethanol was required for stability of the catalytic activity during dialysis. The enzyme could be fractionated with (NH4)2SO4, and 55% of the activity was recovered in the 30-60%-saturation fraction. The product of the reaction contained radioactivity from UDP-[U-14C]galactose and was identified as indol-3-ylacetyl-myo-inositol galactoside by gas chromatography-mass spectrometry. Therefore a UDP-galactose:indol-3-ylacetyl-myo-inositol galactosyltransferase (indol-3-ylacetyl-myo-inositol galactoside synthase) is present in developing kernels of Zea mays. The description of this enzyme, together with the enzymes described in the accompanying paper [Michalczuk & Bandurski (1982) Biochem. J. 207, 273-281] for the synthesis of indol-3-ylacetylglucose and indol-3-ylacetyl-myo-inositol, now provides mechanisms for the biosynthesis of one-half of the low-molecular-weight esters of indol-3-ylacetic acid in Zea mays.

  16. Shapes of Mixed Phospholipid Vesicles

    PubMed Central

    Aranda-Espinoza, Helim; Maldonado, Amir

    2006-01-01

    We studied the shape of phospholipid vesicles prepared by hydration of a mixture of phosphatidylcholine (SOPC) and phosphatidylserine (SOPS) in different proportions. The aim of the work is to obtain some insight into the influence of the chemical composition of a biomembrane on its shape. The optical microscopy results show that the shape of the vesicles depend on the SOPC:SOPS composition. For low SOPS contents, coiled cylindrical vesicles are observed. The results suggest that specific compositions of the SOPC:SOPS vesicles produce some spontaneous curvature on the membrane and then a coiling instability. PMID:19669461

  17. Interaction of caldesmon with phospholipids.

    PubMed Central

    Czuryło, E A; Zborowski, J; Dabrowska, R

    1993-01-01

    The interaction of caldesmon with liposomes composed of various phospholipids has been examined by tryptophan fluorescence spectroscopy. The results indicate that caldesmon makes its strongest complex with phosphatidylserine (PS) vesicles (Kass. = 1.45 x 10(5) M-1). Both electrostatic and hydrophobic interactions contribute to the stability of this complex. The site for strong binding of PS seems to be located in the N-terminal part of the 34 kDa C-terminal fragment of caldesmon. Binding of PS at this site results in displacement of calmodulin from its complex with caldesmon. Images Figure 4 PMID:8484721

  18. Inositol (1,4,5)-trisphosphate activates a calcium channel in isolated sarcoplasmic reticulum membranes.

    PubMed Central

    Suárez-Isla, B. A.; Irribarra, V.; Oberhauser, A.; Larralde, L.; Bull, R.; Hidalgo, C.; Jaimovich, E.

    1988-01-01

    Sarcoplasmic reticulum membrane vesicles isolated from frog skeletal muscle display high conductance calcium channels when fused into phospholipid bilayers. The channels are selective for calcium and barium over Tris. The fractional open time was voltage-independent (-40 to +25 mV), but was steeply dependent on the free cis [Ca2+] (P0 = 0.02 at 10 microM cis Ca2+ and 0.77 at 150 microM Ca2+; estimated Hill coefficient: 1.6). Addition of ATP (1 mM; cis) further increased P0 from 0.77 to 0.94. Calcium activation was reversed by addition of EGTA to the cis compartment. Magnesium (2 mM) increased the frequency of rapid closures and 8 mM magnesium decreased the current amplitude from 3.4 to 1.2 pA at 0 mV, suggesting a reversible fast blockade. Addition of increasing concentrations of inositol (1, 4, 5)-triphosphate (cis), increased P0 from 0.10 +/- 0.01 (mean +/- SEM) in the control to 0.85 +/- 0.02 at 50 microM in an approximately sigmoidal fashion, with an apparent half-maximal activation at 15 microM inositol (1, 4, 5)-trisphosphate in the presence of 40 microM cis Ca2+. Lower concentrations of this agonist were required to produce a significant increase in P0 when 10 microM or less cis Ca2+ were used. The channel was blocked by the addition to the cis compartment of either 0.5 mM lanthanum, 0.5 microM ruthenium red, or 200 nM ryanodine, all known inhibitors of Ca2+ release from sarcoplasmic reticulum vesicles. These results demonstrate the presence of calcium channels in the sarcoplasmic reticulum from frog skeletal muscle with a pharmacological profile consistent with a role in excitation contraction coupling and with the hypothesis that inositol ( 1,4,5)-trisphosphate is a physiological agonist in this process. PMID:2852037

  19. The Inositol-3-Phosphate Synthase Biosynthetic Enzyme Has Distinct Catalytic and Metabolic Roles

    PubMed Central

    Frej, Anna D.; Clark, Jonathan; Le Roy, Caroline I.; Lilla, Sergio; Thomason, Peter A.; Otto, Grant P.; Churchill, Grant; Insall, Robert H.; Claus, Sandrine P.; Hawkins, Phillip; Stephens, Len

    2016-01-01

    Inositol levels, maintained by the biosynthetic enzyme inositol-3-phosphate synthase (Ino1), are altered in a range of disorders, including bipolar disorder and Alzheimer's disease. To date, most inositol studies have focused on the molecular and cellular effects of inositol depletion without considering Ino1 levels. Here we employ a simple eukaryote, Dictyostelium discoideum, to demonstrate distinct effects of loss of Ino1 and inositol depletion. We show that loss of Ino1 results in an inositol auxotrophy that can be rescued only partially by exogenous inositol. Removal of inositol supplementation from the ino1− mutant resulted in a rapid 56% reduction in inositol levels, triggering the induction of autophagy, reduced cytokinesis, and substrate adhesion. Inositol depletion also caused a dramatic generalized decrease in phosphoinositide levels that was rescued by inositol supplementation. However, loss of Ino1 triggered broad metabolic changes consistent with the induction of a catabolic state that was not rescued by inositol supplementation. These data suggest a metabolic role for Ino1 that is independent of inositol biosynthesis. To characterize this role, an Ino1 binding partner containing SEL1L1 domains (Q54IX5) and having homology to mammalian macromolecular complex adaptor proteins was identified. Our findings therefore identify a new role for Ino1, independent of inositol biosynthesis, with broad effects on cell metabolism. PMID:26951199

  20. Inositol trisphosphate and activators of protein kinase C modulate membrane currents in tail motor neurons of Aplysia.

    PubMed

    Sawada, M; Cleary, L J; Byrne, J H

    1989-02-01

    1. We have investigated how activation of the inositol lipid second messenger pathway may contribute to modulation of membrane currents in tail motor neurons of Aplysia. Specifically, we examined the effects of injected inositol 1,4,5-trisphosphate (IP3) and analogues of diacylglycerol (DAG), both of which are products of the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2). 2. Injection of IP3 produced an outward current associated with an apparent increase in membrane conductance. Ion substitution experiments, the sensitivity of the response to low concentrations of TEA and its attenuation by intracellular injections of EGTA suggest that the current produced by injection of IP3 is a calcium-activated K+ current (IK,Ca). 3. The response to IP3 was mimicked by intracellular injection of Ca2+. Injection of Ca2+ produced an outward current that was associated with an apparent increase in input conductance of the membrane. The same manipulations that affected the response to IP3 (see above) also affected the response to injections of Ca2+. 4. Injections of activators of protein kinase C (PKC) produced a relatively slow inward current. The inward current has not been fully analyzed, but it does not appear to be due to the actions of any single conventional ion channel. 5. Activators of PKC attenuated responses to subsequent injections of IP3 indicating that one component of PIP2 hydrolysis can attenuate the other. 6. The results suggest that hydrolysis of inositol phospholipids is a mechanism for regulation of membrane properties in tail motor neurons of Aplysia.

  1. Inositol 1,4-bisphosphate is an allosteric activator of muscle-type 6-phosphofructo-1-kinase.

    PubMed Central

    Mayr, G W

    1989-01-01

    The allosteric effects of various inositol biphosphate (InsP2) isomers and other inositol phosphates, of glycerophosphoinositol phosphates (GroPInsPx) and of phosphoinositides (PtdInsPx) on muscle-type 6-phosphofructo-1-kinase (PFK) were investigated. The binding of these substances to PFK was indirectly estimated by their ability to stabilize the tetrameric enzyme. At near-physiological concentrations of other allosteric effectors, muscle PFK was activated AMP-dependently by Ins(1,4)P2 (Ka = 43 microM), Ins(2,4)P2 (Ka = 70 microM) and GroPIns4P (Ka = 20 microM). These compounds activated PFK by a mechanism similar to that established for activating hexose bisphosphates. Indirect binding experiments indicated minimal Kd,app. values of about 5 microM for the binding of Ins(1,4)P2 in the presence of 0.1 mM-AMP at pH 7.4. This apparent affinity was comparable with that of fructose 1,6-bisphosphate and glucose 1,6-bisphosphate at identical conditions. The enzyme was also found to interact specifically with PtdIns4P (Kd,app. = 37 microM), the inositol phospholipid carrying Ins(1,4)P2 as its head group. The regulatory behaviour of muscle-type PFK in vitro and the concentrations of Ins(1,4)P2 in vivo (between 4 and greater than 50 nmol/g wet wt. of tissue) are consistent with the hypothesis that there is a functional interaction in vivo. Furthermore, a role of PtdIns4P in membrane compartmentation of PFK is suggested. Comparative experiments with liver PFK indicate that these regulatory properties may be relatively specific for the muscle isoform. Unlike muscle PFK, the liver isoform was slightly activated by sub-micromolar concentrations of Ins(1,4,5)P3. PMID:2541692

  2. A secreted salivary inositol polyphosphate 5-phosphatase from a blood-feeding insect: allosteric activation by soluble phosphoinositides and phosphatidylserine.

    PubMed

    Andersen, John F; Ribeiro, José M C

    2006-05-02

    Type II inositol polyphosphate 5-phosphatases (IPPs) act on both soluble inositol phosphate and phosphoinositide substrates. In many cases, these enzymes occur as multidomain proteins in which the IPP domain is linked to lipid-binding or additional catalytic domains. Rhodnius prolixus IPPRp exists as an isolated IPP domain which is secreted into the saliva of this blood-feeding insect. It shows selectivity for soluble and lipid substrates having a 1,4,5-trisphosphate substitution pattern while only poorly hydrolyzing substrates containing a D3 phosphate. With soluble diC8 PI(4,5)P(2) as a substrate, sigmoidal kinetics were observed, suggesting the presence of allosteric activation sites. Surprisingly, IPPRp-mediated hydrolysis of PI(4,5)P(2) and PI(3,4,5)P(3) was also stimulated up to 100-fold by diC8 PI(4)P and diC8 phosphatidylserine (PS). The activation kinetics were again sigmoidal, demonstrating that the allosteric sites recognize nonsubstrate phospholipids. Activation was positively cooperative, and analysis by the Hill equation suggests that at least three to four allosteric sites are present. In a vesicular system, hydrolysis of PI(4,5)P(2) followed a surface dilution kinetic model, and as expected, PS was found to be strongly stimulatory. If allosteric activation of type II IPPs by PI(4)P and PS is a widespread feature of the group, it may represent a novel regulatory mechanism for these important enzymes.

  3. Relationship between stimulated phosphatidic acid production and inositol lipid hydrolysis in intestinal longitudinal smooth muscle from guinea pig.

    PubMed

    Mallows, R S; Bolton, T B

    1987-06-15

    Accumulation of [32P]phosphatidic acid (PA) and total [3H]inositol phosphates (IPs) was measured in the longitudinal smooth-muscle layer from guinea-pig small intestine. Stimulation with carbachol, histamine and substance P produced increases in accumulation of both [3H]IPs and [32P]PA over the same concentration range. The increase in [32P]PA accumulation in response to carbachol (1 microM-0.1 mM) was inhibited in the presence of atropine (0.5 microM). Buffering the external free [Ca2+] to 10 nM did not prevent the carbachol-stimulated increase in [32P]PA accumulation. Carbachol and Ca2+ appear to act synergistically to increase accumulation of [32P]PA. In contrast, although incubation with noradrenaline also increased accumulation of [3H]IPs, no increase in accumulation of [32P]PA could be detected. These results suggest that an increase in formation of IPs is not necessarily accompanied by an increase in PA formation, and imply the existence of receptor-modulated pathways regulating PA concentrations other than by phospholipase-C-catalysed inositol phospholipid hydrolysis.

  4. Electrostatic control of phospholipid polymorphism.

    PubMed

    Tarahovsky, Y S; Arsenault, A L; MacDonald, R C; McIntosh, T J; Epand, R M

    2000-12-01

    A regular progression of polymorphic phase behavior was observed for mixtures of the anionic phospholipid, cardiolipin, and the cationic phospholipid derivative, 1, 2-dioleoyl-sn-glycero-3-ethylphosphocholine. As revealed by freeze-fracture electron microscopy and small-angle x-ray diffraction, whereas the two lipids separately assume only lamellar phases, their mixtures exhibit a symmetrical (depending on charge ratio and not polarity) sequence of nonlamellar phases. The inverted hexagonal phase, H(II,) formed from equimolar mixtures of the two lipids, i.e., at net charge neutrality (charge ratio (CR((+/-))) = 1:1). When one type of lipid was in significant excess (CR((+/-)) = 2:1 or CR((+/-)) = 1:2), a bicontinuous cubic structure was observed. These cubic phases were very similar to those sometimes present in cellular organelles that contain cardiolipin. Increasing the excess of cationic or anionic charge to CR((+/-)) = 4:1 or CR((+/-)) = 1:4 led to the appearance of membrane bilayers with numerous interlamellar contacts, i.e., sponge structures. It is evident that interactions between cationic and anionic moieties can influence the packing of polar heads and hence control polymorphic phase transitions. The facile isothermal, polymorphic interconversion of these lipids may have important biological and technical implications.

  5. Phospholipid Metabolism in Ferrobacillus ferrooxidans

    PubMed Central

    Short, Steven A.; White, David C.; Aleem, M. I. H.

    1969-01-01

    The lipid composition of the chemoautotroph Ferrobacillus ferrooxidans has been examined. Fatty acids represent 2% of the dry weight of the cells and 86% of the total are extractable with organic solvents. About 25% of the total fatty acids are associated with diacyl phospholipids. Polar carotenoids, the benzoquinone coenzyme Q-8, and most of the fatty acids are present in the neutral lipids. The phospholipids have been identified as phosphatidyl monomethylethanolamine (42%), phosphatidyl glycerol (23%), phosphatidyl ethanolamine (20%), cardiolipin (13%), phosphatidyl choline (1.5%), and phosphatidyl dimethylethanolamine (1%) by chromatography of the diacyl lipids, by chromatography in four systems of the glycerol phosphate esters derived from the lipids by mild alkaline methanolysis, and by chromatographic identification of the products of acid hydrolysis of the esters. No trace of phosphatidylserine (PS), glycerolphosphorylserine, or serine could be detected in the lipid extract or in derivatives of that extract. This casts some doubt on the postulated involvement of PS in iron metabolism. After growth in the presence of 14C and 32P, there was essentially no difference in the turnover of either isotope in the glycerolphosphate ester derived from each lipid in cells grown at pH 1.5 or 3.5. Images PMID:5802599

  6. Phospholipid liposomes functionalized by protein

    NASA Astrophysics Data System (ADS)

    Glukhova, O. E.; Savostyanov, G. V.; Grishina, O. A.

    2015-03-01

    Finding new ways to deliver neurotrophic drugs to the brain in newborns is one of the contemporary problems of medicine and pharmaceutical industry. Modern researches in this field indicate the promising prospects of supramolecular transport systems for targeted drug delivery to the brain which can overcome the blood-brain barrier (BBB). Thus, the solution of this problem is actual not only for medicine, but also for society as a whole because it determines the health of future generations. Phospholipid liposomes due to combination of lipo- and hydrophilic properties are considered as the main future objects in medicine for drug delivery through the BBB as well as increasing their bioavailability and toxicity. Liposomes functionalized by various proteins were used as transport systems for ease of liposomes use. Designing of modification oligosaccharide of liposomes surface is promising in the last decade because it enables the delivery of liposomes to specific receptor of human cells by selecting ligand and it is widely used in pharmacology for the treatment of several diseases. The purpose of this work is creation of a coarse-grained model of bilayer of phospholipid liposomes, functionalized by specific to the structural elements of the BBB proteins, as well as prediction of the most favorable orientation and position of the molecules in the generated complex by methods of molecular docking for the formation of the structure. Investigation of activity of the ligand molecule to protein receptor of human cells by the methods of molecular dynamics was carried out.

  7. The use of natural and synthetic phospholipids as pharmaceutical excipients*

    PubMed Central

    van Hoogevest, Peter; Wendel, Armin

    2014-01-01

    In pharmaceutical formulations, phospholipids obtained from plant or animal sources and synthetic phospholipids are used. Natural phospholipids are purified from, e.g., soybeans or egg yolk using non-toxic solvent extraction and chromatographic procedures with low consumption of energy and minimum possible waste. Because of the use of validated purification procedures and sourcing of raw materials with consistent quality, the resulting products differing in phosphatidylcholine content possess an excellent batch to batch reproducibility with respect to phospholipid and fatty acid composition. The natural phospholipids are described in pharmacopeias and relevant regulatory guidance documentation of the Food and Drug Administration (FDA) and European Medicines Agency (EMA). Synthetic phospholipids with specific polar head group, fatty acid composition can be manufactured using various synthesis routes. Synthetic phospholipids with the natural stereochemical configuration are preferably synthesized from glycerophosphocholine (GPC), which is obtained from natural phospholipids, using acylation and enzyme catalyzed reactions. Synthetic phospholipids play compared to natural phospholipid (including hydrogenated phospholipids), as derived from the number of drug products containing synthetic phospholipids, a minor role. Only in a few pharmaceutical products synthetic phospholipids are used. Natural phospholipids are used in oral, dermal, and parenteral products including liposomes. Natural phospholipids instead of synthetic phospholipids should be selected as phospholipid excipients for formulation development, whenever possible, because natural phospholipids are derived from renewable sources and produced with more ecologically friendly processes and are available in larger scale at relatively low costs compared to synthetic phospholipids. Practical applications: For selection of phospholipid excipients for pharmaceutical formulations, natural phospholipids are preferred

  8. The use of natural and synthetic phospholipids as pharmaceutical excipients.

    PubMed

    van Hoogevest, Peter; Wendel, Armin

    2014-09-01

    In pharmaceutical formulations, phospholipids obtained from plant or animal sources and synthetic phospholipids are used. Natural phospholipids are purified from, e.g., soybeans or egg yolk using non-toxic solvent extraction and chromatographic procedures with low consumption of energy and minimum possible waste. Because of the use of validated purification procedures and sourcing of raw materials with consistent quality, the resulting products differing in phosphatidylcholine content possess an excellent batch to batch reproducibility with respect to phospholipid and fatty acid composition. The natural phospholipids are described in pharmacopeias and relevant regulatory guidance documentation of the Food and Drug Administration (FDA) and European Medicines Agency (EMA). Synthetic phospholipids with specific polar head group, fatty acid composition can be manufactured using various synthesis routes. Synthetic phospholipids with the natural stereochemical configuration are preferably synthesized from glycerophosphocholine (GPC), which is obtained from natural phospholipids, using acylation and enzyme catalyzed reactions. Synthetic phospholipids play compared to natural phospholipid (including hydrogenated phospholipids), as derived from the number of drug products containing synthetic phospholipids, a minor role. Only in a few pharmaceutical products synthetic phospholipids are used. Natural phospholipids are used in oral, dermal, and parenteral products including liposomes. Natural phospholipids instead of synthetic phospholipids should be selected as phospholipid excipients for formulation development, whenever possible, because natural phospholipids are derived from renewable sources and produced with more ecologically friendly processes and are available in larger scale at relatively low costs compared to synthetic phospholipids. Practical applications: For selection of phospholipid excipients for pharmaceutical formulations, natural phospholipids are preferred

  9. [Effects of phospholipids on oxidative demethylation of dimethylcyclohexylamine by cumene hydroperoxide involving methemoglobin].

    PubMed

    Kiseleva, S N; Khatyleva, S Iu; Kisel', M A; Kiselev, P A; Akhrem, A A

    1981-12-01

    The reaction of oxidative demethylation of N-dimethylcyclohexylamine by cumene hydroperoxide involving methemoglobin was studied. Data from differential spectroscopy and kinetic analysis revealed the formation of a methemoglobin--N-dimethylcyclohexylamine--cumene hydroperoxide complex. The inhibiting analysis revealed the radical stages in the process of demethylation. An addition to the reaction mixture of phosphatidyl serine, phosphatidyl inositol and lysophosphatidyl choline at a ratio of 50 divided by 500 molecules per 1 molecule of protein increased the rate of the reaction product accumulation 2--3-fold. Phosphatidyl choline and the ionic detergent sodium cholate did not practically affect the reaction rate under the given experimental conditions. The nature of the activating effect of some phospholipids on oxidative demethylation is discussed.

  10. Phospholipids in plant and animal chromatin.

    PubMed

    Viola-Magni, M P; Gahan, P B; Pacy, J

    1985-01-01

    Isolated hepatic nuclei and hepatic chromatin have been analysed for their DNA, RNA, protein and phospholipid content. The protein/DNA ratio is 3 for nuclei and 1.95 for chromatin extracted from Triton X-100 treated nuclei. The phospholipids, (2.36 +/- 0.91 (S.D.) per cent of the total nuclear material), are lost during the chromatin preparation mainly during the Triton X-100 washings of the nuclei. Nevertheless, 10 per cent of the total nuclear phospholipids remain bound to the chromatin. The comparative analysis of both nuclei and chromatin shows a difference in phospholipids and fatty acid composition. Thus, the chromatin-associated phospholipid cannot be attributed simply to contaminating nuclear membrane. This is supported by the autoradiographic study of semi-thin sections of interphase nuclei from root apices of Vicia faba in which [3H] ethanolamine is clearly localized in the chromatin and nucleolar regions of the nuclei.

  11. Inositol Trisphosphate Receptor Ca2+ Release Channels

    PubMed Central

    FOSKETT, J. KEVIN; WHITE, CARL; CHEUNG, KING-HO; MAK, DON-ON DANIEL

    2010-01-01

    The inositol 1,4,5-trisphosphate (InsP3) receptors (InsP3Rs) are a family of Ca2+ release channels localized predominately in the endoplasmic reticulum of all cell types. They function to release Ca2+ into the cytoplasm in response to InsP3 produced by diverse stimuli, generating complex local and global Ca2+ signals that regulate numerous cell physiological processes ranging from gene transcription to secretion to learning and memory. The InsP3R is a calcium-selective cation channel whose gating is regulated not only by InsP3, but by other ligands as well, in particular cytoplasmic Ca2+. Over the last decade, detailed quantitative studies of InsP3R channel function and its regulation by ligands and interacting proteins have provided new insights into a remarkable richness of channel regulation and of the structural aspects that underlie signal transduction and permeation. Here, we focus on these developments and review and synthesize the literature regarding the structure and single-channel properties of the InsP3R. PMID:17429043

  12. Assaying inositol and phosphoinositide phosphatase enzymes.

    PubMed

    Donahue, Janet L; Ercetin, Mustafa; Gillaspy, Glenda E

    2013-01-01

    One critical aspect of phosphoinositide signaling is the turnover of signaling molecules in the pathway. These signaling molecules include the phosphatidylinositol phosphates (PtdInsPs) and inositol phosphates (InsPs). The enzymes that catalyze the breakdown of these molecules are thus important potential regulators of signaling, and in many cases the activity of such enzymes needs to be measured and compared to other enzymes. PtdInsPs and InsPs are broken down by sequential dephosphorylation reactions which are catalyzed by a set of specific phosphatases. Many of the phosphatases can act on both PtdInsP and InsP substrates. The protocols described in this chapter detail activity assays that allow for the measurement of PtdInsP and InsP phosphatase activities in vitro starting with native or recombinant enzymes. Three different assays are described that have different equipment requirements and allow one to test a range of PtdInsP and InsP phosphatases that act on different substrates.

  13. Modulation of inositol polyphosphate levels regulates neuronal differentiation

    PubMed Central

    Loss, Omar; Wu, Chun Ting; Riccio, Antonella; Saiardi, Adolfo

    2013-01-01

    The binding of neurotrophins to tropomyosin receptor kinase receptors initiates several signaling pathways, including the activation of phospholipase C-γ, which promotes the release of diacylglycerol and inositol 1,4,5-trisphosphate (IP3). In addition to recycling back to inositol, IP3 serves as a precursor for the synthesis of higher phosphorylated inositols, such as inositol 1,3,4,5,6-pentakisphosphate (IP5) and inositol hexakisphosphate (IP6). Previous studies on the effect of neurotrophins on inositol signaling were limited to the analysis of IP3 and its dephosphorylation products. Here we demonstrate that nerve growth factor (NGF) regulates the levels of IP5 and IP6 during PC12 differentiation. Furthermore, both NGF and brain-derived neurotrophic factor alter IP5 and IP6 intracellular ratio in differentiated PC12 cells and primary neurons. Neurotrophins specifically regulate the expression of IP5-2 kinase (IP5-2K), which phosphorylates IP5 into IP6. IP5-2K is rapidly induced after NGF treatment, but its transcriptional levels sharply decrease in fully differentiated PC12 cells. Reduction of IP5-2K protein levels by small interfering RNA has an effect on the early stages of PC12 cell differentiation, whereas fully differentiated cells are not affected. Conversely, perturbation of IP5-2K levels by overexpression suggests that both differentiated PC12 cells and sympathetic neurons require low levels of the enzyme for survival. Therefore maintaining appropriate intracellular levels of inositol polyphosphates is necessary for neuronal survival and differentiation. PMID:23864704

  14. Reflections on inositol(s) for PCOS therapy: steps toward success.

    PubMed

    Nestler, John E; Unfer, Vittorio

    2015-07-01

    In polycystic ovary syndrome (PCOS) pathogenesis, both the insulin resistance and the related compensatory hyperinsulinemia are involved. Despite their similarities, Myo-inositol (MI) and d-chiro-inositol (DCI) play different roles in PCOS etiology and therapy. Indeed, in tissue such as the liver both molecules are involved in the insulin signaling, i.e. MI promotes glucose uptake and DCI glycogen synthesis. In reproductive tissue such as the ovary, MI regulates glucose uptake and follicle stimulating hormone (FSH) signaling, whereas DCI is devoted to the insulin-mediated androgen production. The new hypothesis on "DCI paradox" in the ovary has provided the key for a better understanding. Unlike other tissues, ovary is not insulin resistant, indeed because the epimerase enzyme, which converts MI to DCI, is insulin dependent, the "DCI paradox" hypothesis suggests that in the ovary of PCOS women, an increased epimerase activity leads to a DCI overproduction and MI depletion. This imbalance could be the cause of the poor oocyte quality and the impairment in the FSH signaling. Owing to this situation, the focal point is the administration of both MI and DCI in a proper ratio for treating PCOS. This topic, with several other "hot" issues, was the driving thread in the discussion between the two scientists.

  15. Egg phospholipids and cardiovascular health.

    PubMed

    Blesso, Christopher N

    2015-04-13

    Eggs are a major source of phospholipids (PL) in the Western diet. Dietary PL have emerged as a potential source of bioactive lipids that may have widespread effects on pathways related to inflammation, cholesterol metabolism, and high-density lipoprotein (HDL) function. Based on pre-clinical studies, egg phosphatidylcholine (PC) and sphingomyelin appear to regulate cholesterol absorption and inflammation. In clinical studies, egg PL intake is associated with beneficial changes in biomarkers related to HDL reverse cholesterol transport. Recently, egg PC was shown to be a substrate for the generation of trimethylamine N-oxide (TMAO), a gut microbe-dependent metabolite associated with increased cardiovascular disease (CVD) risk. More research is warranted to examine potential serum TMAO responses with chronic egg ingestion and in different populations, such as diabetics. In this review, the recent basic science, clinical, and epidemiological findings examining egg PL intake and risk of CVD are summarized.

  16. Phospholipid Vesicles in Materials Science

    SciTech Connect

    Granick, Steve

    2016-05-11

    The objective of this research was to develop the science basis needed to deploy phospholipid vesicles as functional materials in energy contexts. Specifically, we sought to: (1) Develop an integrated molecular-level understanding of what determines their dynamical shape, spatial organization, and responsiveness to complex, time-varying environments; and (2) Develop understanding of their active transportation in crowded environments, which our preliminary measurements in cells suggest may hold design principles for targeting improved energy efficiency in new materials systems. The methods to do this largely involved fluorescence imaging and other spectroscopy involving single particles, vesicles, particles, DNA, and endosomes. An unexpected importance outcome was a new method to image light-emitting diodes during actual operation using super-resolution spectroscopy.

  17. Egg Phospholipids and Cardiovascular Health

    PubMed Central

    Blesso, Christopher N.

    2015-01-01

    Eggs are a major source of phospholipids (PL) in the Western diet. Dietary PL have emerged as a potential source of bioactive lipids that may have widespread effects on pathways related to inflammation, cholesterol metabolism, and high-density lipoprotein (HDL) function. Based on pre-clinical studies, egg phosphatidylcholine (PC) and sphingomyelin appear to regulate cholesterol absorption and inflammation. In clinical studies, egg PL intake is associated with beneficial changes in biomarkers related to HDL reverse cholesterol transport. Recently, egg PC was shown to be a substrate for the generation of trimethylamine N-oxide (TMAO), a gut microbe-dependent metabolite associated with increased cardiovascular disease (CVD) risk. More research is warranted to examine potential serum TMAO responses with chronic egg ingestion and in different populations, such as diabetics. In this review, the recent basic science, clinical, and epidemiological findings examining egg PL intake and risk of CVD are summarized. PMID:25871489

  18. Myo-inositol reduces β-catenin activation in colitis

    PubMed Central

    Bradford, Emily M; Thompson, Corey A; Goretsky, Tatiana; Yang, Guang-Yu; Rodriguez, Luz M; Li, Linheng; Barrett, Terrence A

    2017-01-01

    AIM To assess dietary myo-inositol in reducing stem cell activation in colitis, and validate pβ-cateninS552 as a biomarker of recurrent dysplasia. METHODS We examined the effects of dietary myo-inositol treatment on inflammation, pβ-cateninS552 and pAkt levels by histology and western blot in IL-10-/- and dextran sodium sulfate-treated colitic mice. Additionally, we assessed nuclear pβ-cateninS552 in patients treated with myo-inositol in a clinical trial, and in patients with and without a history of colitis-induced dysplasia. RESULTS In mice, pβ-cateninS552 staining faithfully reported the effects of myo-inositol in reducing inflammation and intestinal stem cell activation. In a pilot clinical trial of myo-inositol administration in patients with a history of low grade dysplasia (LGD), two patients had reduced numbers of intestinal stem cell activation compared to the placebo control patient. In humans, pβ-cateninS552 staining discriminated ulcerative colitis patients with a history of LGD from those with benign disease. CONCLUSION Enumerating crypts with increased numbers of pβ-cateninS552 - positive cells can be utilized as a biomarker in colitis-associated cancer chemoprevention trials. PMID:28811707

  19. Inositol Treatment and ART Outcomes in Women with PCOS.

    PubMed

    Garg, Deepika; Tal, Reshef

    2016-01-01

    Polycystic ovary syndrome (PCOS) affects 5-10% of women in reproductive age and is characterized by oligo/amenorrhea, androgen excess, insulin resistance, and typical polycystic ovarian morphology. It is the most common cause of infertility secondary to ovulatory dysfunction. The underlying etiology is still unknown but is believed to be multifactorial. Insulin-sensitizing compounds such as inositol, a B-complex vitamin, and its stereoisomers (myo-inositol and D-chiro-inositol) have been studied as an effective treatment of PCOS. Administration of inositol in PCOS has been shown to improve not only the metabolic and hormonal parameters but also ovarian function and the response to assisted-reproductive technology (ART). Accumulating evidence suggests that it is also capable of improving folliculogenesis and embryo quality and increasing the mature oocyte yield following ovarian stimulation for ART in women with PCOS. In the current review, we collate the evidence and summarize our current knowledge on ovarian stimulation and ART outcomes following inositol treatment in women with PCOS undergoing in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI).

  20. New Functions of the Inositol Polyphosphate 5-Phosphatases in Cancer.

    PubMed

    Erneux, Christophe; Ghosh, Somadri; Ramos, Ana Raquel; Edimo, William's Elong

    2016-01-01

    Inositol polyphosphate 5-phosphatases act on inositol phosphates and phosphoinositides as substrates. They are 10 different isoenzymes and several splice variants in the human genome that are involved in a series of human pathologies such as the Lowe syndrome, the Joubert and MORM syndromes, breast cancer, glioblastoma, gastric cancer and several other type of cancers. Inositol 5-phosphatases can be amplified in human cancer cells, whereas the 3- and 4- phosphatase tumor suppressor PTEN and INPP4B, repectively are often repressed or deleted. The inositol 5-phosphatases are critically involved in a complex network of higly regulated phosphoinositides, affecting the lipid content of PI(3, 4, 5)P3, PI(4, 5)P2 and PI(3, 4)P2. This has an impact on the normal behavior of many intracellular target proteins e.g. protein kinase B (PKB/Akt) or actin binding proteins and final biological responses. The production of PI(3, 4P)2 by dephosphorylation of the substrate PI(3, 4, 5)P3 is particularly important as it produces a new signal messenger in the control of cell migration, invasion and endocytosis. New inhibitors/activators of inositol 5- phosphatases have recently been identified for the possible control of their activity in several human pathologies such as inflamation and cancer.

  1. Inositol Treatment and ART Outcomes in Women with PCOS

    PubMed Central

    Garg, Deepika

    2016-01-01

    Polycystic ovary syndrome (PCOS) affects 5–10% of women in reproductive age and is characterized by oligo/amenorrhea, androgen excess, insulin resistance, and typical polycystic ovarian morphology. It is the most common cause of infertility secondary to ovulatory dysfunction. The underlying etiology is still unknown but is believed to be multifactorial. Insulin-sensitizing compounds such as inositol, a B-complex vitamin, and its stereoisomers (myo-inositol and D-chiro-inositol) have been studied as an effective treatment of PCOS. Administration of inositol in PCOS has been shown to improve not only the metabolic and hormonal parameters but also ovarian function and the response to assisted-reproductive technology (ART). Accumulating evidence suggests that it is also capable of improving folliculogenesis and embryo quality and increasing the mature oocyte yield following ovarian stimulation for ART in women with PCOS. In the current review, we collate the evidence and summarize our current knowledge on ovarian stimulation and ART outcomes following inositol treatment in women with PCOS undergoing in vitro fertilization (IVF) and/or intracytoplasmic sperm injection (ICSI). PMID:27795706

  2. Polycystic Ovary Syndrome: Insights into the Therapeutic Approach with Inositols

    PubMed Central

    Sortino, Maria A.; Salomone, Salvatore; Carruba, Michele O.; Drago, Filippo

    2017-01-01

    Polycystic ovary syndrome (PCOS) is characterized by hormonal abnormalities that cause menstrual irregularity and reduce ovulation rate and fertility, associated to insulin resistance. Myo-inositol (cis-1,2,3,5-trans-4,6-cyclohexanehexol, MI) and D-chiro-inositol (cis-1,2,4-trans-3,5,6-cyclohexanehexol, DCI) represent promising treatments for PCOS, having shown some therapeutic benefits without substantial side effects. Because the use of inositols for treating PCOS is widespread, a deep understanding of this treatment option is needed, both in terms of potential mechanisms and efficacy. This review summarizes the current knowledge on the biological effects of MI and DCI and the results obtained from relevant intervention studies with inositols in PCOS. Based on the published results, both MI and DCI represent potential valid therapeutic approaches for the treatment of insulin resistance and its associated metabolic and reproductive disorders, such as those occurring in women affected by PCOS. Furthermore, the combination MI/DCI seems also effective and might be even superior to either inositol species alone. However, based on available data, a particular MI:DCI ratio to be administered to PCOS patients cannot be established. Further studies are then necessary to understand the real contents of MI or DCI uptaken by the ovary following oral administration in order to identify optimal doses and/or combination ratios. PMID:28642705

  3. Leukotriene B/sub 4/ (LTB/sub 4/) induces formation of inositol-phosphates (IP's) in rat peritoneal polymorphonuclear leukocytes (PMN's)

    SciTech Connect

    Chi-Rosso, G.; Crooke, S.T.; Mong, S.

    1986-05-01

    LTB/sub 4/ induced rapid breakdown of prelabeled inositol-phospholipids (PI) in rat PMN. Formation of (/sup 3/H)-inositol-trisphosphate ((/sup 3/H)-IP/sub 3/) was rapid, with a peak of 250-300% of the control level, after 5-15 sec of stimulation with LTB/sub 4/. Accumulation of (/sup 3/H)-inositol-bisphosphate ((/sup 3/H)-IP/sub 2/) was rapid, peaking after 30 sec of stimulation. (/sup 3/H)-inositol-monophosphate ((/sup 3/H)-IP/sub 1/) accumulated gradually in the presence of LiCl. The kinetics of (/sup 3/H)-IP/sub 3/, (/sup 3/H)-IP/sub 2/ and (/sup 3/H)-IP/sub 1/ accumulation suggested that LTB/sub 4/ may interact with receptors in PMNs, activate phospholipase C which, in turn, induces hydrolysis of PI. The agonist activities of several LTB/sub 4/ analogs were employed to investigate the structure activity relationship of LTB/sub 4/ receptor mediated activation of PI hydrolysis. Increases in (/sup 3/H)-IP/sub 3/ formation were dependent upon the concentration of LTB/sub 4/ and the agonist analogs. The rank order potency of these analogs were equivalent to that of the pharmacological activity of LTB/sub 4/ agonists in the chemotaxis assay. Furthermore, the Islet activation protein (IAP) inhibited LTB/sub 4/ induced (/sup 3/H)-IP/sub 3/ formation. The tumor promoting phorbomyristate ester also inhibited LTB/sub 4/ induced (/sup 3/H)-IP/sub 3/ formation. These results suggest LTB/sub 4/ may interact with receptors in rat PMNs, activate G/sub i/ protein regulated phospholipase C and induce (/sup 3/H)-IP/sub 3/ formation.

  4. Synthesis of fagopyritols A1 and B1 from D-chiro-inositol.

    PubMed

    Cid, M Belén; Alfonso, Francisco; Martín-Lomas, Manuel

    2004-09-13

    Fagopyritol A1 (3-O-alpha-d-galactopyranosyl-d-chiro-inositol) and fagopyritol B1 (2-O-alpha-d-galactopyranosyl-d-chiro-inositol) have been synthesized by glycosylation of the diequatorial diol 1,4,5,6-tetra-O-benzoyl-d-chiro-inositol, readily obtained from d-chiro-inositol, with 2,3,4,6-tetra-O-benzyl-d-galactopyranosyl trichloroacetimidate.

  5. Human Sodium/Inositol Cotransporter 2 (SMIT2) Transports Inositols But Not Glucose in L6 Cells

    PubMed Central

    Lin, Xiaobo; Ma, Lina; Fitzgerald, Robin L.; Ostlund, Richard E.

    2013-01-01

    Summary To characterize the function of the sodium/inositol symporter SMIT2 in skeletal muscle, human SMIT2 cDNA was transfected into L6 myoblasts using pcDNA3.1 expression vector. Compared with the pcDNA3.1 vector only transfection, this overexpression increased the uptake of [3H]D-chiro-inositol (DCI) by 159-fold. [3H]myo-Inositol uptake increased by 37-fold. In contrast, [14C]D-glucose, [14C]2-deoxy-D-glucose, or [14C]3-O-methyl-D-glucose uptake remained unchanged in the presence of either 0, 5.5, or 25 mM unlabeled glucose. The Km of DCI and myo-inositol for DCI uptake was 111.0 and 158.0 μM, respectively, whereas glucose competed for DCI uptake with a Ki of 6.1 mM. Insulin treatment of non-transfected L6 cells (2 μM for 24 hours) increased [3H]DCI specific uptake 18-fold. DCI transport is up regulated by insulin and competitively inhibited by millimolar levels of glucose. Therefore, expression and/or function of SMIT2, a high affinity transporter specific for DCI and myo-inositol, may be reduced in diabetes mellitus, insulin resistance and polycystic ovary syndrome causing the abnormal DCI metabolism observed in these conditions. PMID:19032932

  6. SCS3 and YFT2 Link Transcription of Phospholipid Biosynthetic Genes to ER Stress and the UPR

    PubMed Central

    Moir, Robyn D.; Gross, David A.; Silver, David L.; Willis, Ian M.

    2012-01-01

    The ability to store nutrients in lipid droplets (LDs) is an ancient function that provides the primary source of metabolic energy during periods of nutrient insufficiency and between meals. The Fat storage-Inducing Transmembrane (FIT) proteins are conserved ER–resident proteins that facilitate fat storage by partitioning energy-rich triglycerides into LDs. FIT2, the ancient ortholog of the FIT gene family first identified in mammals has two homologs in Saccharomyces cerevisiae (SCS3 and YFT2) and other fungi of the Saccharomycotina lineage. Despite the coevolution of these genes for more than 170 million years and their divergence from higher eukaryotes, SCS3, YFT2, and the human FIT2 gene retain some common functions: expression of the yeast genes in a human embryonic kidney cell line promotes LD formation, and expression of human FIT2 in yeast rescues the inositol auxotrophy and chemical and genetic phenotypes of strains lacking SCS3. To better understand the function of SCS3 and YFT2, we investigated the chemical sensitivities of strains deleted for either or both genes and identified synthetic genetic interactions against the viable yeast gene-deletion collection. We show that SCS3 and YFT2 have shared and unique functions that connect major biosynthetic processes critical for cell growth. These include lipid metabolism, vesicular trafficking, transcription of phospholipid biosynthetic genes, and protein synthesis. The genetic data indicate that optimal strain fitness requires a balance between phospholipid synthesis and protein synthesis and that deletion of SCS3 and YFT2 impacts a regulatory mechanism that coordinates these processes. Part of this mechanism involves a role for SCS3 in communicating changes in the ER (e.g. due to low inositol) to Opi1-regulated transcription of phospholipid biosynthetic genes. We conclude that SCS3 and YFT2 are required for normal ER membrane biosynthesis in response to perturbations in lipid metabolism and ER stress. PMID

  7. LIPID PEROXIDATION GENERATES BIOLOGICALLY ACTIVE PHOSPHOLIPIDS INCLUDING OXIDATIVELY N-MODIFIED PHOSPHOLIPIDS

    PubMed Central

    Davies, Sean S.; Guo, Lilu

    2014-01-01

    Peroxidation of membranes and lipoproteins converts “inert” phospholipids into a plethora of oxidatively modified phospholipids (oxPL) that can act as signaling molecules. In this review, we will discuss four major classes of oxPL: mildly oxygenated phospholipids, phospholipids with oxidatively truncated acyl chains, phospholipids with cyclized acyl chains, and phospholipids that have been oxidatively N-modified on their headgroups by reactive lipid species. For each class of oxPL we will review the chemical mechanisms of their formation, the evidence for their formation in biological samples, the biological activities and signaling pathways associated with them, and the catabolic pathways for their elimination. We will end by briefly highlighting some of the critical questions that remain about the role of oxPL in physiology and disease. PMID:24704586

  8. Brain inositol is a novel stimulator for promoting Cryptococcus penetration of the blood-brain barrier.

    PubMed

    Liu, Tong-Bao; Kim, Jong-Chul; Wang, Yina; Toffaletti, Dena L; Eugenin, Eliseo; Perfect, John R; Kim, Kee Jun; Xue, Chaoyang

    2013-01-01

    Cryptococcus neoformans is the most common cause of fungal meningitis, with high mortality and morbidity. The reason for the frequent occurrence of Cryptococcus infection in the central nervous system (CNS) is poorly understood. The facts that human and animal brains contain abundant inositol and that Cryptococcus has a sophisticated system for the acquisition of inositol from the environment suggests that host inositol utilization may contribute to the development of cryptococcal meningitis. In this study, we found that inositol plays an important role in Cryptococcus traversal across the blood-brain barrier (BBB) both in an in vitro human BBB model and in in vivo animal models. The capacity of inositol to stimulate BBB crossing was dependent upon fungal inositol transporters, indicated by a 70% reduction in transmigration efficiency in mutant strains lacking two major inositol transporters, Itr1a and Itr3c. Upregulation of genes involved in the inositol catabolic pathway was evident in a microarray analysis following inositol treatment. In addition, inositol increased the production of hyaluronic acid in Cryptococcus cells, which is a ligand known to binding host CD44 receptor for their invasion. These studies suggest an inositol-dependent Cryptococcus traversal of the BBB, and support our hypothesis that utilization of host-derived inositol by Cryptococcus contributes to CNS infection.

  9. Anion exchange chromatographic separation of inositol phosphates and their quantification by gas chromatography.

    PubMed

    Heathers, G P; Juehne, T; Rubin, L J; Corr, P B; Evers, A S

    1989-01-01

    The direct measurement of mass of inositol trisphosphate from biologic samples is described. Separation of inositol monophosphate, bisphosphate, trisphosphate, and inositol tetrakisphosphate was achieved using anion exchange chromatography with a sodium sulfate gradient. In addition, separation of the isomers of each inositol phosphate was performed using HPLC procedures. The individual inositol phosphate fractions were subsequently dephosphorylated and desalted. The myo-inositol from each fraction was then derivatized to the hexatrimethylsilyl derivative and the myo-inositol derivatives were quantified by a novel gas chromatographic analysis using the hexatrimethylsilyl derivative of chiro-inositol as an internal concentration reference. This method is a reproducible and relatively rapid procedure for the direct quantification of inositol phosphate mass which overcomes many of the problems associated with the use of radiolabeled precursors. The method is a significant improvement over existing procedures for the quantitative determination of the mass of inositol phosphate by virtue of improved recovery, sensitivity, and technical simplicity. The applicability of this method is illustrated by the quantitative determination of inositol trisphosphate in response to norepinephrine stimulation of adult canine myocytes and cerebral cortical brain slices and by measurement of the isomers of inositol trisphosphate in isolated myocytes.

  10. Sleep Disturbance Preceding Completed Suicide in Adolescents

    ERIC Educational Resources Information Center

    Goldstein, Tina R.; Bridge, Jeffrey A.; Brent, David A.

    2008-01-01

    We examined sleep difficulties preceding death in a sample of adolescent suicide completers as compared with a matched sample of community control adolescents. Sleep disturbances were assessed in 140 adolescent suicide victims with a psychological autopsy protocol and in 131 controls with a similar semistructured psychiatric interview. Rates of…

  11. Generation of precedence relations for mechanical assemblies

    NASA Technical Reports Server (NTRS)

    Zhang, Hui; Sanderson, A. C.

    1989-01-01

    Planning of assembly sequences is essential to the manufacturing system design process. Several methodologies have been proposed to represent all the feasible assembly sequences. In this thesis, three algorithms are presented to generate three sets of precedence relations based on all the infeasible assembly tasks, all the infeasible assembly states, and all the feasible assembly sequences, respectively. The equivalence of the resulting sets of precedence relations to the AND/OR graph is established. A new property, the real time property, of a representation of assembly sequences is defined and discussed. A representation of assembly sequences is said to have the real time property, if it is possible to generate the next assembly task by testing locally in the representation, and it will guarantee that the generated assembly task will not lead the assembly sequence to a dead end situation, in which no feasible assembly task can be performed any more. It is shown that the correctness and completeness of one representation can not guarantee the real time property of the representation. It is proven that the directed graph representation and the set of precedence relations based on all the infeasible assembly states have the real time property, while the AND/OR graph representation and the set of precedence relations based on all the infeasible assembly tasks do not have the real time property. Finally in the thesis, the PLEIDEAS system, a PLanning Environment for Integrated DEsign of Assembly Systems, is described and illustrated by an example.

  12. Sleep Disturbance Preceding Completed Suicide in Adolescents

    ERIC Educational Resources Information Center

    Goldstein, Tina R.; Bridge, Jeffrey A.; Brent, David A.

    2008-01-01

    We examined sleep difficulties preceding death in a sample of adolescent suicide completers as compared with a matched sample of community control adolescents. Sleep disturbances were assessed in 140 adolescent suicide victims with a psychological autopsy protocol and in 131 controls with a similar semistructured psychiatric interview. Rates of…

  13. Chronotropic incompetence precedes silent pulmonary embolism.

    PubMed

    Mahadevan, Karunasai; Silverman, Lawrence M; Becker, Daniel M

    2014-01-01

    A patient with recurrent pulmonary emboli collected heart rate data during exercise, which provided important premorbid clues to changes in cardiopulmonary exercise tolerance coincident with accrual of thrombus in the central circulation. On both occasions, chronotropic incompetence (CI) preceded the pulmonary emboli events. When patients with programmed exercise goals notice CI, they should seek professional guidance.

  14. On the Rhetoric and Precedents of Racism.

    ERIC Educational Resources Information Center

    Villanueva, Victor

    1999-01-01

    Considers contribution of rhetorical training of the Aztecs prior to the European conquest as well as other early philosophers from the Americas. Encourages breaking precedent in order to battle racism by looking to rhetorical training developed in the Americas and Puerto Rico in addition to the European thinkers. (SC)

  15. On the Rhetoric and Precedents of Racism.

    ERIC Educational Resources Information Center

    Villanueva, Victor

    1999-01-01

    Considers contribution of rhetorical training of the Aztecs prior to the European conquest as well as other early philosophers from the Americas. Encourages breaking precedent in order to battle racism by looking to rhetorical training developed in the Americas and Puerto Rico in addition to the European thinkers. (SC)

  16. Thrombotic thrombocytopenic purpura preceding systemic lupus erythematosus.

    PubMed Central

    Simeon-Aznar, C P; Cuenca-Luque, R; Fonollosa-Pla, V; Bosch-Gil, J A

    1992-01-01

    The case of a patient admitted with thrombotic thrombocytopenic purpura nine years after developing systemic lupus erythematosus (SLE) is reported. Thrombotic thrombocytopenic purpura associated with SLE has been described on other occasions, but in most patients the diagnosis of SLE precedes that of thrombotic thrombocytopenic purpura. The unusual sequence and the chronological separation of the two diseases is emphasised. PMID:1575591

  17. More Than the Rules of Precedence

    ERIC Educational Resources Information Center

    Liang, Yawei

    2005-01-01

    In a fundamental computer-programming course, such as CSE101, questions about how to evaluate an arithmetic expression are frequently used to check if our students know the rules of precedence. The author uses two of our final examination questions to show that more knowledge of computer science is needed to answer them correctly. Furthermore,…

  18. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In...

  19. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In...

  20. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In...

  1. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In...

  2. 32 CFR 700.501 - Precedence.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commandant of the Marine Corps § 700.501 Precedence. The Commandant of the Marine Corps, while so serving, has the grade of general. In...

  3. Inositol Hexaphosphate and Inositol Inhibit Colorectal Cancer Metastasis to the Liver in BALB/c Mice

    PubMed Central

    Fu, Min; Song, Yang; Wen, Zhaoxia; Lu, Xingyi; Cui, Lianhua

    2016-01-01

    Inositol hexaphosphate (IP6) and inositol (Ins), naturally occurring carbohydrates present in most mammals and plants, inhibit the growth of numerous cancers both in vitro and in vivo. In this study, we first examined the anti-metastatic effects of IP6 and Ins using a liver metastasis model of colorectal cancer (CRC) in BALB/c mice. CT-26 cells were injected into the splenic capsule of 48 BALB/c mice. The mice were then randomly divided into four groups: IP6, Ins, IP6 + Ins and normal saline control (n = 12 per group). IP6 and/or Ins (80 mg/kg each, 0.2 mL/day) were injected into the gastrointestinal tracts of the mice on the second day after surgery. All mice were sacrificed after 20 days, and the tumor inhibition rates were determined. The results demonstrated that the tumor weights of liver metastases and the tumor inhibition rates were reduced in the experimental groups compared to the control group and that treatment with the combination of IP6 and Ins resulted in greater inhibition of tumor growth than treatment with either compound alone. These findings suggest that IP6 and Ins prevent the development and metastatic progression of colorectal cancer to the liver in mice by altering expression of the extracellular matrix proteins collagen IV, fibronectin and laminin; the adhesion factor receptor integrin-β1; the proteolytic enzyme matrix metalloproteinase 9; and the angiogenic factors vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor beta in the tumor metastasis microenvironment. In conclusion, IP6 and Ins inhibited the development and metastatic progression of colorectal cancer to the liver in BALB/c mice, and the effect of their combined application was significantly greater than the effect of either compound alone. This evidence supports further testing of the combined application of IP6 and Ins for the prevention of colorectal cancer metastasis to the liver in clinical studies. PMID:27187454

  4. Inositol Hexaphosphate and Inositol Inhibit Colorectal Cancer Metastasis to the Liver in BALB/c Mice.

    PubMed

    Fu, Min; Song, Yang; Wen, Zhaoxia; Lu, Xingyi; Cui, Lianhua

    2016-05-12

    Inositol hexaphosphate (IP6) and inositol (Ins), naturally occurring carbohydrates present in most mammals and plants, inhibit the growth of numerous cancers both in vitro and in vivo. In this study, we first examined the anti-metastatic effects of IP6 and Ins using a liver metastasis model of colorectal cancer (CRC) in BALB/c mice. CT-26 cells were injected into the splenic capsule of 48 BALB/c mice. The mice were then randomly divided into four groups: IP6, Ins, IP6 + Ins and normal saline control (n = 12 per group). IP6 and/or Ins (80 mg/kg each, 0.2 mL/day) were injected into the gastrointestinal tracts of the mice on the second day after surgery. All mice were sacrificed after 20 days, and the tumor inhibition rates were determined. The results demonstrated that the tumor weights of liver metastases and the tumor inhibition rates were reduced in the experimental groups compared to the control group and that treatment with the combination of IP6 and Ins resulted in greater inhibition of tumor growth than treatment with either compound alone. These findings suggest that IP6 and Ins prevent the development and metastatic progression of colorectal cancer to the liver in mice by altering expression of the extracellular matrix proteins collagen IV, fibronectin and laminin; the adhesion factor receptor integrin-β1; the proteolytic enzyme matrix metalloproteinase 9; and the angiogenic factors vascular endothelial growth factor, basic fibroblast growth factor, and transforming growth factor beta in the tumor metastasis microenvironment. In conclusion, IP6 and Ins inhibited the development and metastatic progression of colorectal cancer to the liver in BALB/c mice, and the effect of their combined application was significantly greater than the effect of either compound alone. This evidence supports further testing of the combined application of IP6 and Ins for the prevention of colorectal cancer metastasis to the liver in clinical studies.

  5. Calcium-dependent phospholipid catabolism and arachidonic acid mobilization in cerebral minces

    SciTech Connect

    Damron, D.S.; Dorman, R.V. )

    1990-06-01

    Cerebral minces were used to investigate the role of calcium influx on trauma-induced alterations of brain lipid metabolism. Cerebral phospholipids, nonpolar lipids, and free fatty acids were radiolabeled in vivo with ({sup 3}H)arachidonic acid. Tissue incubation stimulated the time-dependent catabolism of choline and inositol glycerophospholipids, and resulted in the accumulation of ({sup 3}H)free fatty acids. These effects were attenuated in Ca{sup 2}{sup +}-free incubations, and when EGTA or verapamil were present. The inhibition of calcium influx also reduced the labeling of diglycerides, whereas ethanolamine and serine glycerophospholipids were not affected by incubation or treatments. Replacing Ca{sup 2}{sup +} with other cations also attenuated the incubation-dependent alterations in lipid metabolism. However, only cadmium was able to compete with calcium and reduce the accumulation of ({sup 3}H)free fatty acids. It appeared that about half of the observed phospholipid catabolism was dependent on Ca{sup 2}{sup +} influx and that at least 80% of the ({sup 3}H)free fatty acid accumulation required calcium.

  6. Role of an Expanded Inositol Transporter Repertoire in Cryptococcus neoformans Sexual Reproduction and Virulence

    PubMed Central

    Xue, Chaoyang; Liu, Tongbao; Chen, Lydia; Li, Wenjun; Liu, Iris; Kronstad, James W.; Seyfang, Andreas; Heitman, Joseph

    2010-01-01

    ABSTRACT Cryptococcus neoformans and Cryptococcus gattii are globally distributed human fungal pathogens and the leading causes of fungal meningitis. Recent studies reveal that myo-inositol is an important factor for fungal sexual reproduction. That C. neoformans can utilize myo-inositol as a sole carbon source and the existence of abundant inositol in the human central nervous system suggest that inositol is important for Cryptococcus development and virulence. In accord with this central importance of inositol, an expanded myo-inositol transporter (ITR) gene family has been identified in Cryptococcus. This gene family contains two phylogenetically distinct groups, with a total of 10 or more members in C. neoformans and at least six members in the sibling species C. gattii. These inositol transporter genes are differentially expressed under inositol-inducing conditions based on quantitative real-time PCR analyses. Expression of ITR genes in a Saccharomyces cerevisiae itr1 itr2 mutant lacking inositol transport can complement the slow-growth phenotype of this strain, confirming that ITR genes are bona fide inositol transporters. Gene mutagenesis studies reveal that the Itr1 and Itr1A transporters are important for myo-inositol stimulation of mating and that functional redundancies among the myo-inositol transporters likely exist. Deletion of the inositol 1-phosphate synthase gene INO1 in an itr1 or itr1a mutant background compromised virulence in a murine inhalation model, indicating the importance of inositol sensing and acquisition for fungal infectivity. Our study provides a platform for further understanding the roles of inositol in fungal physiology and virulence. PMID:20689743

  7. Gravimetric determination of phospholipid concentration.

    PubMed

    Tejera-Garcia, Roberto; Connell, Lisa; Shaw, Walter A; Kinnunen, Paavo K J

    2012-09-01

    Accurate determination of lipid concentrations is an obligatory routine in a research laboratory engaged in studies using this class of biomaterials. For phospholipids, this is frequently accomplished using the phosphate assay (Bartlett, G.R. Phosphorus Assay in Column Chromatography. J. Biol. Chem. 234, 466-468, 1959). Given the purity of the currently commercially available synthetic and isolated natural lipids, we have observed that determination of the dry weight of lipid stock solutions provides the fastest, most accurate, and generic method to assay their concentrations. The protocol described here takes advantage of the high resolution and accuracy obtained by modern weighing technology. We assayed by this technique the concentrations of a number of phosphatidylcholine samples, with different degrees of acyl chain saturation and length, and in different organic solvents. The results were compared with those from Bartlett assay, (31)P NMR, and Langmuir compression isotherms. The data obtained show that the gravimetric assay yields lipid concentrations with a resolution similar or better than obtained by the other techniques. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  8. Dielectrophoresis of Functional Phospholipid Vesicles

    NASA Astrophysics Data System (ADS)

    Froude, Victoria; Zhu, Yingxi Elaine

    2008-03-01

    Recently, there has been an emerging interest in using AC-dielectrophoresis (DEP) to transport and assemble phospholipid vesicles (liposomes) and nanoparticles to form functional bio-assemblies where the underlying charge polarization mechanism of colloids in AC fields strongly depends on nano-scaled surface charge. In this work, we study liposomes segregation and aggregation in the presence of nanocolloids and salts in which the biological functionality of liposomes is augmented by the physical functionality of inorganic coating and particles. Liposomes, synthesized by sonication with 1,2-Dioleoyl-sn-Glycero-3-Phosphate (DOPA), are manipulated at varied AC-field frequencies across fabricated micro-electrodes in a quadrapole configuration on glass. We observe the co-assembly of liposome and opposite-charged nanocolloids by confocal microscopy and SEM, where the smaller nanocolloids are captured in between liposome junctions to form stabilized composite vesicles at several distinct frequencies. We observe a strong dependence of the liposome DEP mobility on the number of nanoparticles present in suspension and propose a new mechanism based on charge segregation and charged nanocolloid entrainment in the double layer.

  9. Method for lipidomic analysis: p53 expression modulation of sulfatide, ganglioside, and phospholipid composition of U87 MG glioblastoma cells.

    PubMed

    He, Huan; Conrad, Charles A; Nilsson, Carol L; Ji, Yongjie; Schaub, Tanner M; Marshall, Alan G; Emmett, Mark R

    2007-11-15

    Lipidomics can complement genomics and proteomics by providing new insight into dynamic changes in biomembranes; however, few reports in the literature have explored, on an organism-wide scale, the functional link between nonenzymatic proteins and cellular lipids. Here, we report changes induced by adenovirus-delivered wild-type p53 gene and chemotherapy of U87 MG glioblastoma cells, a treatment known to trigger apoptosis and cell cycle arrest. We compare polar lipid changes in treated cells and control cells by use of a novel, sensitive method that employs lipid extraction, one-step liquid chromatography separation, high-resolution mass analysis, and Kendrick mass defect analysis. Nano-LC FT-ICR MS and quadrupole linear ion trap MS/MS analysis of polar lipids yields hundreds of unique assignments of glyco- and phospholipids at sub-ppm mass accuracy and high resolving power (m/Deltam50% = 200 000 at m/z 400) at 1 s/scan. MS/MS data confirm molecular structures in many instances. Sulfatides are most highly modulated by wild-type p53 treatment. The treatment also leads to an increase in phospholipids such as phosphatidyl inositols, phosphatidyl serines, phosphatidyl glycerols, and phosphatidyl ethanolamines. An increase in hydroxylated phospholipids is especially noteworthy. Also, a decrease in the longer chain gangliosides, GD1 and GM1b, is observed in wild-type p53 (treated) cells.

  10. Chemoprevention of pulmonary carcinogenesis by myo-inositol.

    PubMed

    Wattenberg, L W

    1999-01-01

    This abstract summarizes material presented at the "First International Symposium on Disease Prevention by IP6 and other Rice Components "held in Kyoto, Japan in June, 1998. The presentation deals primarily with studies of chemoprevention of pulmonary carcinogenesis by myo-inositol. This compound is largely formed by the dephosphorylation of inositol hexaphosphate (IP6, phytate) within the gastrointestinal tract in humans and animals. myo-Inositol is one of a relatively few compounds that has an inhibitory effect on carcinogenesis of the lung in experimental animals when administered during the post-initiation period. It prevents pulmonary adenoma formation in A/J mice when fed in the diet subsequent to administrations of benzo[a]pyrene or the tobacco specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) to the mice. A second compound, dexamethasone, also prevents pulmonary neoplasia under the same conditions. Experiments in which both myo-inositol and dexamethasone were administered together in the diet showed an additive inhibitory effect. The significance and utility of the chemopreventive properties of these agents remains to be determined.

  11. Using inositol as a biocompatible ligand for efficient transgene expression

    PubMed Central

    Zhang, Lei; Bellis, Susan L; Fan, Yiwen; Wu, Yunkun

    2015-01-01

    Transgene transfection techniques using cationic polymers such as polyethylenimines (PEIs) and PEI derivatives as gene vectors have shown efficacy, although they also have shortcomings. PEIs have decent DNA-binding capability and good cell internalization performance, but they cannot deliver gene payloads very efficiently to cell nuclei. In this study, three hyperbranched polyglycerol-polyethylenimine (PG6-PEI) polymers conjugated with myo-inositol (INO) molecules were developed. The three resulting PG6-PEI-INO polymers have an increased number of INO ligands per molecule. PG6-PEI-INO 1 had only 14 carboxymethyl INO (CMINO) units per molecule. PG6-PEI-INO 2 had approximately 130 CMINO units per molecule. PG6-PEI-INO 3 had as high as 415 CMINO units approximately. Mixing PG6-PEI-INO polymers with DNA produced compact nanocomposites. We then performed localization studies using fluorescent microscopy. As the number of conjugated inositol ligands increased in PG6-PEI-INO polymers, there was a corresponding increase in accumulation of the polymers within 293T cell nuclei. Transfection performed with spherical 293T cells yielded 82% of EGFP-positive cells when using PG6-PEI-INO 3 as the vehicle. Studies further revealed that extracellular adenosine triphosphate (eATP) can inhibit the transgene efficiency of PG6-PEI-INO polymers, as compared with PEI and PG6-PEI that were not conjugated with inositol. Our work unveiled the possibility of using inositol as an effective ligand for transgene expression. PMID:25926732

  12. Comparison between effects of myo-inositol and D-chiro-inositol on ovarian function and metabolic factors in women with PCOS.

    PubMed

    Pizzo, Alfonsa; Laganà, Antonio Simone; Barbaro, Luisa

    2014-03-01

    Myo-inositol and D-chiro-inositol are capable of improving the ovarian function and metabolism of polycystic ovary syndrome (PCOS) patients. The aim of this work is to compare the effects of myo-inositol and D-chiro-inositol in PCOS. We enrolled 50 patients, with homogeneous bio-physical features, affected by PCOS and menstrual irregularities, and we randomly divided them into two groups: 25 were treated with 4 g of myo-inositol/die plus 400 mcg of folic acid/die orally for six months, 25 with 1 g of D-chiro-inositol/die plus 400 mcg of folic acid/die orally for six months. We analyzed in both groups pre-treatment and post-treatment BMI, systolic and diastolic blood pressure, Ferriman-Gallwey score, Cremoncini score, serum LH, LH/FSH ratio, total and free testosterone, dehydroepiandrosterone sulfate (DHEA-S), Δ-4-androstenedione, SHBG, prolactin, glucose/immunoreactive insulin (IRI) ratio, homeostatic model assessment (HOMA) index, and the resumption of regular menstrual cycles. Both the isoforms of inositol were effective in improving ovarian function and metabolism in patients with PCOS, although myo-inositol showed the most marked effect on the metabolic profile, whereas D-chiro-inositol reduced hyperandrogenism better.

  13. Patterns of seismic activity preceding large earthquakes

    NASA Technical Reports Server (NTRS)

    Shaw, Bruce E.; Carlson, J. M.; Langer, J. S.

    1992-01-01

    A mechanical model of seismic faults is employed to investigate the seismic activities that occur prior to major events. The block-and-spring model dynamically generates a statistical distribution of smaller slipping events that precede large events, and the results satisfy the Gutenberg-Richter law. The scaling behavior during a loading cycle suggests small but systematic variations in space and time with maximum activity acceleration near the future epicenter. Activity patterns inferred from data on seismicity in California demonstrate a regional aspect; increased activity in certain areas are found to precede major earthquake events. One example is given regarding the Loma Prieta earthquake of 1989 which is located near a fault section associated with increased activity levels.

  14. Metabolomic change precedes apple superficial scald symptoms.

    PubMed

    Rudell, David R; Mattheis, James P; Hertog, Maarten L A T M

    2009-09-23

    Untargeted metabolic profiling was employed to characterize metabolomic changes associated with 'Granny Smith' apple superficial scald development following 1-MCP or DPA treatment. Partial least-squares discriminant analyses were used to link metabolites with scald, postharvest treatments, and storage duration. Models revealed metabolomic differentiation between untreated controls and fruit treated with DPA or 1-MCP within 1 week following storage initiation. Metabolic divergence between controls and DPA-treated fruit after 4 weeks of storage preceded scald symptom development by 2 months. alpha-Farnesene oxidation products with known associations to scald, including conjugated trienols, 6-methyl-5-hepten-2-one, and 6-methyl-5-hepten-2-ol, were associated with presymptomatic as well as scalded control fruit. Likewise, a large group of putative triterpenoids with mass spectral features similar to those of ursolic acid and beta-sitosterol were associated with control fruit and scald. Results demonstrate that extensive metabolomic changes associated with scald precede actual symptom development.

  15. Patterns of seismic activity preceding large earthquakes

    NASA Technical Reports Server (NTRS)

    Shaw, Bruce E.; Carlson, J. M.; Langer, J. S.

    1992-01-01

    A mechanical model of seismic faults is employed to investigate the seismic activities that occur prior to major events. The block-and-spring model dynamically generates a statistical distribution of smaller slipping events that precede large events, and the results satisfy the Gutenberg-Richter law. The scaling behavior during a loading cycle suggests small but systematic variations in space and time with maximum activity acceleration near the future epicenter. Activity patterns inferred from data on seismicity in California demonstrate a regional aspect; increased activity in certain areas are found to precede major earthquake events. One example is given regarding the Loma Prieta earthquake of 1989 which is located near a fault section associated with increased activity levels.

  16. Membrane-Derived Phospholipids Control Synaptic Neurotransmission and Plasticity

    PubMed Central

    García-Morales, Victoria; Montero, Fernando; González-Forero, David; Rodríguez-Bey, Guillermo; Gómez-Pérez, Laura; Medialdea-Wandossell, María Jesús; Domínguez-Vías, Germán; García-Verdugo, José Manuel; Moreno-López, Bernardo

    2015-01-01

    Synaptic communication is a dynamic process that is key to the regulation of neuronal excitability and information processing in the brain. To date, however, the molecular signals controlling synaptic dynamics have been poorly understood. Membrane-derived bioactive phospholipids are potential candidates to control short-term tuning of synaptic signaling, a plastic event essential for information processing at both the cellular and neuronal network levels in the brain. Here, we showed that phospholipids affect excitatory and inhibitory neurotransmission by different degrees, loci, and mechanisms of action. Signaling triggered by lysophosphatidic acid (LPA) evoked rapid and reversible depression of excitatory and inhibitory postsynaptic currents. At excitatory synapses, LPA-induced depression depended on LPA1/Gαi/o-protein/phospholipase C/myosin light chain kinase cascade at the presynaptic site. LPA increased myosin light chain phosphorylation, which is known to trigger actomyosin contraction, and reduced the number of synaptic vesicles docked to active zones in excitatory boutons. At inhibitory synapses, postsynaptic LPA signaling led to dephosphorylation, and internalization of the GABAAγ2 subunit through the LPA1/Gα12/13-protein/RhoA/Rho kinase/calcineurin pathway. However, LPA-induced depression of GABAergic transmission was correlated with an endocytosis-independent reduction of GABAA receptors, possibly by GABAAγ2 dephosphorylation and subsequent increased lateral diffusion. Furthermore, endogenous LPA signaling, mainly via LPA1, mediated activity-dependent inhibitory depression in a model of experimental synaptic plasticity. Finally, LPA signaling, most likely restraining the excitatory drive incoming to motoneurons, regulated performance of motor output commands, a basic brain processing task. We propose that lysophospholipids serve as potential local messengers that tune synaptic strength to precedent activity of the neuron. PMID:25996636

  17. Phospholipid interactions in model membrane systems. II. Theory.

    PubMed Central

    Stigter, D; Mingins, J; Dill, K A

    1992-01-01

    We describe statistical thermodynamic theory for the lateral interactions among phospholipid head groups in monolayers and bilayers. Extensive monolayer experiments show that at low surface densities, PC head groups have strong lateral repulsions which increase considerably with temperature, whereas PE interactions are much weaker and have no significant temperature dependence (see the preceding paper). In previous work, we showed that the second virial coefficients for these interactions can be explained by: (a) steric repulsions among the head groups, and (b) a tilting of the P-N+ dipole of PC so that the N+ end enters the oil phase, to an extent that increases with temperature. It was also predicted that PE interactions should be weaker and less temperature dependent because the N+ terminal of the PE head-group is hydrophilic, hence, it is tilted into the water phase, so dipolar contributions among PE's are negligible due to the high dielectric constant of water. In the present work, we broaden the theory to treat phospholipid interactions up to higher lateral surface densities. We generalize the Hill interfacial virial expansion to account for dipoles and to include the third virial term. We show that to account for the large third virial coefficients for both PC and PE requires that the short range lateral attractions among the head groups also be taken into account. In addition, the third virial coefficient includes fluctuating head group dipoles, computed by Monte Carlo integration assuming pairwise additivity of the instantaneous pair potentials. We find that because the dipole fluctuations are correlated, the average triplet interactions do not equal the sum of the average dipole pair potentials. This is important for predicting, the magnitude and the independence of temperature of the third virial coefficients for PC. The consistency of the theory with data of both the second and the third virial coefficients extends the applicability of the head

  18. Health effects of dietary phospholipids.

    PubMed

    Küllenberg, Daniela; Taylor, Lenka A; Schneider, Michael; Massing, Ulrich

    2012-01-05

    Beneficial effects of dietary phospholipids (PLs) have been mentioned since the early 1900's in relation to different illnesses and symptoms, e.g. coronary heart disease, inflammation or cancer. This article gives a summary of the most common therapeutic uses of dietary PLs to provide an overview of their approved and proposed benefits; and to identify further investigational needs.From the majority of the studies it became evident that dietary PLs have a positive impact in several diseases, apparently without severe side effects. Furthermore, they were shown to reduce side effects of some drugs. Both effects can partially be explained by the fact that PL are highly effective in delivering their fatty acid (FA) residues for incorporation into the membranes of cells involved in different diseases, e.g. immune or cancer cells. The altered membrane composition is assumed to have effects on the activity of membrane proteins (e.g. receptors) by affecting the microstructure of membranes and, therefore, the characteristics of the cellular membrane, e.g. of lipid rafts, or by influencing the biosynthesis of FA derived lipid second messengers. However, since the FAs originally bound to the applied PLs are increased in the cellular membrane after their consumption or supplementation, the FA composition of the PL and thus the type of PL is crucial for its effect. Here, we have reviewed the effects of PL from soy, egg yolk, milk and marine sources. Most studies have been performed in vitro or in animals and only limited evidence is available for the benefit of PL supplementation in humans. More research is needed to understand the impact of PL supplementation and confirm its health benefits.

  19. Nonenzymatic Reactions above Phospholipid Surfaces of Biological Membranes: Reactivity of Phospholipids and Their Oxidation Derivatives

    PubMed Central

    Solís-Calero, Christian; Ortega-Castro, Joaquín; Frau, Juan; Muñoz, Francisco

    2015-01-01

    Phospholipids play multiple and essential roles in cells, as components of biological membranes. Although phospholipid bilayers provide the supporting matrix and surface for many enzymatic reactions, their inherent reactivity and possible catalytic role have not been highlighted. As other biomolecules, phospholipids are frequent targets of nonenzymatic modifications by reactive substances including oxidants and glycating agents which conduct to the formation of advanced lipoxidation end products (ALEs) and advanced glycation end products (AGEs). There are some theoretical studies about the mechanisms of reactions related to these processes on phosphatidylethanolamine surfaces, which hypothesize that cell membrane phospholipids surface environment could enhance some reactions through a catalyst effect. On the other hand, the phospholipid bilayers are susceptible to oxidative damage by oxidant agents as reactive oxygen species (ROS). Molecular dynamics simulations performed on phospholipid bilayers models, which include modified phospholipids by these reactions and subsequent reactions that conduct to formation of ALEs and AGEs, have revealed changes in the molecular interactions and biophysical properties of these bilayers as consequence of these reactions. Then, more studies are desirable which could correlate the biophysics of modified phospholipids with metabolism in processes such as aging and diseases such as diabetes, atherosclerosis, and Alzheimer's disease. PMID:25977746

  20. Cutaneous presentation preceding acute monocytic leukemia

    PubMed Central

    Jin, Xianhua; Li, Fuqiu; Li, Xue; Zhu, Wenjing; Mou, Yan; Huang, Yang; Zhao, Huanyu; Gao, Wei; Xia, Jianxin

    2017-01-01

    Abstract Rationale: Cutaneous presentation preceding acute myeloid leukemia (AML) is rare, and the prognosis is poor. Patient concerns: We report 4 cases of AML cutis, where skin infiltration precedes any blood or bone marrow evidence of leukemia. We also reviewed 13 cases reported in English and Chinese literature. The 4 cases all presented typical cutaneous lesions without any systemic evidence of leukemia. Histopathological examination found that dense monomorphous cell infiltration involved the dermis. Some cells surrounded blood vessels and skin appendages in a concentric manner or showed single-row arrangement in the collagen fiber bundles. Uninvolved papillary dermis was found to separate normal epidermis from dermal infiltration. Minor cells had a large kidney-shaped or oval nucleus with nucleoli and slightly eosinophilic cytoplasm. Immunohistochemical analysis was positive for CD4, CD56, while CD123 was negative in all cases. Diagnoses: AML-M5. Interventions: 2 patients received chemotherapy ,but others rejected treatment. Outcomes: Most patients died within 1 year after the onset of skin lesions. Lessons: These findings suggest that skin infiltration of AML may precede any systemic evidence, and typical cutaneous lesions in elderly individuals may be indicative for AML. PMID:28272239

  1. Nontransitivity of sperm precedence in Drosophila.

    PubMed

    Clark, A G; Dermitzakis, E T; Civetta, A

    2000-06-01

    Sperm competition is an important component of fitness in Drosophila, but we still do not have a clear understanding of the unit of selection that is relevant to sperm competition. Here we demonstrate that sperm competitive ability is not a property of the sperm haplotype, but rather of the diploid male's genotype. Then we test whether the relative sperm competitive ability of males can be ranked on a linear array or whether competitive ability instead depends on particular pairwise contests among males. Sperm precedence of six chromosome-extracted lines was tested against three different visible marker lines (cn bw, bwD, and Cy), and the rank order of the six lines differed markedly among the mutant lines. Population genetic theory has shown that departures from transitivity of sperm precedence may be important to the maintenance of polymorphism for genes that influence sperm competitive ability. The nontransitivity seen in sperm precedence should theoretically increase the opportunity for polymorphism in genes that influence this phenotype.

  2. Solution structure and phospholipid interactions of the isolated voltage-sensor domain from KvAP.

    PubMed

    Butterwick, Joel A; MacKinnon, Roderick

    2010-11-05

    Voltage-sensor domains (VSDs) are specialized transmembrane segments that confer voltage sensitivity to many proteins such as ion channels and enzymes. The activities of these domains are highly dependent on both the chemical properties and the physical properties of the surrounding membrane environment. To learn about VSD-lipid interactions, we used nuclear magnetic resonance spectroscopy to determine the structure and phospholipid interface of the VSD from the voltage-dependent K(+) channel KvAP (prokaryotic Kv from Aeropyrum pernix). The solution structure of the KvAP VSD solubilized within phospholipid micelles is similar to a previously determined crystal structure solubilized by a nonionic detergent and complexed with an antibody fragment. The differences observed include a previously unidentified short amphipathic α-helix that precedes the first transmembrane helix and a subtle rigid-body repositioning of the S3-S4 voltage-sensor paddle. Using (15)N relaxation experiments, we show that much of the VSD, including the pronounced kink in S3 and the S3-S4 paddle, is relatively rigid on the picosecond-to-nanosecond timescale. In contrast, the kink in S3 is mobile on the microsecond-to-millisecond timescale and may act as a hinge in the movement of the paddle during channel gating. We characterized the VSD-phospholipid micelle interactions using nuclear Overhauser effect spectroscopy and showed that the micelle uniformly coats the KvAP VSD and approximates the chemical environment of a phospholipid bilayer. Using paramagnetically labeled phospholipids, we show that bilayer-forming lipids interact with the S3 and S4 helices more strongly than with S1 and S2.

  3. Quantification of phospholipids classes in human milk.

    PubMed

    Giuffrida, Francesca; Cruz-Hernandez, Cristina; Flück, Brigitte; Tavazzi, Isabelle; Thakkar, Sagar K; Destaillats, Frédéric; Braun, Marcel

    2013-10-01

    Phospholipids are integral constituents of the milk fat globule membranes and they play a central role in infants' immune and inflammatory responses. A methodology employing liquid chromatography coupled with evaporative light scattering detector has been optimized and validated to quantify the major phospholipids classes in human milk. Phospholipids were extracted using chloroform and methanol and separated on C18 column. Repeatability, intermediate reproducibility, and recovery values were calculated and a large sample set of human milk analyzed. In human milk, phospholipid classes were quantified at concentrations of 0.6 mg/100 g for phosphatidylinositol; 4.2 mg/100 g for phosphatidylethanolamine, 0.4 mg/100 g for phosphatidylserine, 2.8 mg/100 g for phosphatidylcholine, and 4.6 mg/100 g for sphingomyelin. Their relative standard deviation of repeatability and intermediate reproducibility values ranging between 0.8 and 13.4 % and between 2.4 and 25.7 %, respectively. The recovery values ranged between 67 and 112 %. Finally, the validated method was used to quantify phospholipid classes in human milk collected from 50 volunteers 4 weeks postpartum providing absolute content of these lipids in a relatively large cohort. The average content of total phospholipids was 23.8 mg/100 g that corresponds to an estimated mean intake of 140 mg phospholipids/day in a 4-week old infant when exclusively breast-fed.

  4. Filamentous Fungi with High Cytosolic Phospholipid Transfer Activity in the Presence of Exogenous Phospholipid

    PubMed Central

    Record, Eric; Lesage, Laurence; Cahagnier, Bernard; Marion, Didier; Asther, Marcel

    1994-01-01

    The phospholipid transfer activity of cell extracts from 15 filamentous fungus strains grown on a medium containing phospholipids as the carbon source was measured by a fluorescence assay. This assay was based on the transfer of pyrene-labeled phosphatidylcholines forming the donor vesicles to acceptor vesicles composed of egg phosphatidylcholines. The highest phosphatidylcholine transfer activity was obtained with cell extracts from Aspergillus oryzae. The presence of exogenous phospholipids in the culture medium of A. oryzae was shown to increase markedly the activity of phospholipid transfer as well as the pool of exocellular proteins during the primary phase of growth. Modifications in the biochemical marker activities of cellular organelles were observed: succinate dehydrogenase, a mitochondrial marker; inosine diphosphatase, a Golgi system marker; and cytochrome c oxidoreductase, an endoplasmic reticulum marker, were increased 7.3-, 2-, and 22-fold, respectively, when A. oryzae was grown in the presence of phospholipids. PMID:16349388

  5. Inositol-phosphodihydroceramides in the periodontal pathogen Tannerella forsythia: Structural analysis and incorporation of exogenous myo-inositol

    PubMed Central

    Megson, Zoë Anne; Pittenauer, Ernst; Duda, Katarzyna Anna; Engel, Regina; Ortmayr, Karin; Koellensperger, Gunda; Mach, Lukas; Allmaier, Günter; Holst, Otto; Messner, Paul; Schäffer, Christina

    2015-01-01

    Background Unique phosphodihydroceramides containing phosphoethanolamine and glycerol have been previously described in Porphyromonas gingivalis. Importantly, they were shown to possess pro-inflammatory properties. Other common human bacteria were screened for the presence of these lipids, and they were found, amongst others, in the oral pathogen Tannerella forsythia. To date, no detailed study into the lipids of this organism has been performed. Methods Lipids were extracted, separated and purified by HPTLC, and analyzed using GC-MS, ESI–MS and NMR. Of special interest was how T. forsythia acquires the metabolic precursors for the lipids studied here. This was assayed by radioactive and stable isotope incorporation using carbon-14 and deuterium labeled myo-inositol, added to the growth medium. Results T. forsythia synthesizes two phosphodihydroceramides (Tf GL1, Tf GL2) which are constituted by phospho-myo-inositol linked to either a 17-, 18-, or 19-carbon sphinganine, N-linked to either a branched 17:0(3-OH) or a linear 16:0(3-OH) fatty acid which, in Tf GL2, is, in turn, ester-substituted with a branched 15:0 fatty acid. T. forsythia lacks the enzymatic machinery required for myo-inositol synthesis but was found to internalize inositol from the medium for the synthesis of both Tf GL1 and Tf GL2. Conclusion The study describes two novel glycolipids in T. forsythia which could be essential in this organism. Their synthesis could be reliant on an external source of myo-inositol. General significance The effects of these unique lipids on the immune system and their role in bacterial virulence could be relevant in the search for new drug targets. PMID:26277409

  6. Autistic disorder and phospholipids: A review.

    PubMed

    Brown, Christine M; Austin, David W

    2011-01-01

    Dysregulated phospholipid metabolism has been proposed as an underlying biological component of neurodevelopmental disorders such as autistic disorder (AD) and attention-deficit/hyperactivity disorder (ADHD). This review provides an overview of fatty acid and phospholipid metabolism and evidence for phospholipid dysregulation with reference to the membrane hypothesis of schizophrenia. While there is evidence that phospholipid metabolism is at least impaired in individuals with AD, it has not been established whether phospholipid metabolism is implicated in causal, mechanistic or epiphenomenological models. More research is needed to ascertain whether breastfeeding, and specifically, the administration of colostrum or an adequate substitute can play a preventative role by supplying the neonate with essential fatty acids (EFAs) at a critical juncture in their development. Regarding treatment, further clinical trials of EFA supplementation are essential to determine the efficacy of EFAs in reducing AD symptomatology and whether supplementation can serve as a cost-effective and readily available intervention. Crown Copyright © 2010. Published by Elsevier Ltd. All rights reserved.

  7. Polyhydroxyalkanoate (PHA) Granules Have no Phospholipids

    PubMed Central

    Bresan, Stephanie; Sznajder, Anna; Hauf, Waldemar; Forchhammer, Karl; Pfeiffer, Daniel; Jendrossek, Dieter

    2016-01-01

    Polyhydroxybutyrate (PHB) granules, also designated as carbonosomes, are supra-molecular complexes in prokaryotes consisting of a PHB polymer core and a surface layer of structural and functional proteins. The presence of suspected phospholipids in the surface layer is based on in vitro data of isolated PHB granules and is often shown in cartoons of the PHB granule structure in reviews on PHB metabolism. However, the in vivo presence of a phospholipid layer has never been demonstrated. We addressed this topic by the expression of fusion proteins of DsRed2EC and other fluorescent proteins with the phospholipid-binding domain (LactC2) of lactadherin in three model organisms. The fusion proteins specifically localized at the cell membrane of Ralstonia eutropha but did not co-localize with PHB granules. The same result was obtained for Pseudomonas putida, a species that accumulates another type of polyhydroxyalkanoate (PHA) granules related to PHB. Notably, DsRed2EC-LactC2 expressed in Magnetospirillum gryphiswaldense was detected at the position of membrane-enclosed magnetosome chains and at the cytoplasmic membrane but not at PHB granules. In conclusion, the carbonosomes of representatives of α-proteobacteria, β-proteobacteria and γ-proteobacteria have no phospholipids in vivo and we postulate that the PHB/PHA granule surface layers in natural producers generally are free of phospholipids and consist of proteins only. PMID:27222167

  8. Degradation of cholesterol crystals in phospholipids

    NASA Astrophysics Data System (ADS)

    Koren, Eugen; Koscec, Mirna; Fugate, Robert D.

    1993-02-01

    Based on previous studies from the laboratory that demonstrated degradation of cholesterol crystals ingested by macrophages in a cell culture system and indicated that intracellular phospholipids could play an important role in mobilization of crystalline cholesterol, the role of each of the three major intracellular phospholipid species in degradation of crystals is further explored. Fluorescently labeled cholesterol crystals are incubated with phospholipids over a period of 5 d. Morphological changes in crystals are monitored using digital imaging fluorescence microscopy, fluorescence redistribution after photobleaching, confocal microscopy, and epifluorescent and phase contrast microscopy. Results clearly demonstrate that all three phospholipids are able to mobilize crystalline cholesterol. However, the mechanisms by which they exert mobilization are different. Sphingomyelin and phosphatidylchloline are found to cause gradual and uniform dissolution of crystals, more or less preserving their original shape. Phosphatidylethanolamine appear to penetrate into the crystal, causing its fragmentation and solubilization. In the mixture of all three phospholipids representing the composition found in macrophages, both of the described mechanisms are working simultaneously.

  9. Functional redundancy of CDP-ethanolamine and CDP-choline pathway enzymes in phospholipid biosynthesis: ethanolamine-dependent effects on steady-state membrane phospholipid composition in Saccharomyces cerevisiae.

    PubMed Central

    McGee, T P; Skinner, H B; Bankaitis, V A

    1994-01-01

    It has been established that yeast membrane phospholipid content is responsive to the inositol and choline content of the growth medium. Alterations in the levels of transcription of phospholipid biosynthetic enzymes contribute significantly to this response. We now describe conditions under which ethanolamine can exert significant influence on yeast membrane phospholipid composition. We demonstrate that mutations which block a defined subset of the reactions required for the biosynthesis of phosphatidylcholine (PC) via the CDP-choline pathway cause ethanolamine-dependent effects on the steady-state levels of bulk PC in yeast membranes. Such an ethanolamine-dependent reduction in bulk membrane PC content was observed for both choline kinase (cki) and choline phosphotransferase (cpt1) mutants, but it was not observed for mutants defective in cholinephosphate cytidylyltransferase, the enzyme that catalyzes the penultimate reaction of the CDP-choline pathway for PC biosynthesis. Moreover, the ethanolamine effect observed for cki and cpt1 mutants was independent of the choline content of the growth medium. Finally, we found that haploid yeast strains defective in the activity of both the choline and ethanolamine phosphotransferases experienced an ethanolamine-insensitive reduction in steady-state PC content, an effect which was not observed in strains defective in either one of these activities alone. The collective data indicate that specific enzymes of the CDP-ethanolamine pathway for phosphatidylethanolamine biosynthesis, while able to contribute to PC synthesis when yeast cells are grown under conditions of ethanolamine deprivation, do not do so when yeast cells are presented with this phospholipid headgroup precursor. Images PMID:7961445

  10. Electrochemical modelling of QD-phospholipid interactions.

    PubMed

    Zhang, Shengwen; Chen, Rongjun; Malhotra, Girish; Critchley, Kevin; Vakurov, Alexander; Nelson, Andrew

    2014-04-15

    The aggregation of quantum dots (QDs) and capping of individual QDs affects their activity towards biomembrane models. Electrochemical methods using a phospholipid layer on mercury (Hg) membrane model have been used to determine the phospholipid monolayer activity of thioglycollic acid (TGA) coated quantum dots (QDs) as an indicator of biomembrane activity. The particles were characterised for size and charge. The activity of the QDs towards dioleoyl phosphatidylcholine (DOPC) monolayers is pH dependent, and is most active at pH 8.2 within the pH range 8.2-6.5 examined in this work. This pH dependent activity is the result of increased particle aggregation coupled to decreasing surface charge emanating from the TGA carboxylic groups employed to stabilize the QD dispersion in aqueous media. Capping the QDs with CdS/ZnS lowers the particles' activity to phospholipid monolayers. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Metabolism of myo-[2-3H]Inositol and scyllo-[R-3H]Inositol in Ripening Wheat Kernels 1

    PubMed Central

    Sasaki, Ken; Loewus, Frank A.

    1980-01-01

    Injection of myo-[2-3H]inositol or scyllo-[R-3H]inositol into the peduncular cavity of wheat stalks about 2 to 4 weeks postanthesis led to rapid translocation into the spike and accumulation of label in developing kernels, especially the bran fraction. With myo-[2-3H]inositol, about 50 to 60% of the label was incorporated into high molecular weight cell wall substance in the region of the injection. That portion translocated to the kernels was utilized primarily for cell wall polysaccharide formation and phytate biosynthesis. A small amount was recovered as free myo-inositol and galactinol. When scyllo-[R-3H]inositol was supplied, most of the label was translocated into the developing kernels where it accumulated as free scyllo-inositol and O-α-d-galactopyranosyl-scyllo-inositol in approximately equal amount. None of the label from scyllo-[R-3H]inositol was utilized for either phytate biosynthesis or cell wall polysaccharide formation. PMID:16661513

  12. Haemolytic uraemic syndrome preceding acute lymphoblastic leukaemia

    PubMed Central

    Piel, Barbara; Brittain, Christine; Dixon, Alexander

    2011-01-01

    An 11-year-old girl presented with diarrhoea associated haemolytic uraemic syndrome (HUS) requiring haemodialysis. Four weeks following the resolution of her renal impairment, she was found to have cervical lymphadenopathy alongside deterioration in her renal function. While blood films during her acute illness were indicative of sepsis only, subsequent film revealed a diagnosis of acute lymphoblastic leukaemia (ALL). Thus, this report describes a rare case of diarrhoea associated HUS preceding the diagnosis of ALL, and may represent an unusual presentation of the malignancy. PMID:22679186

  13. Oral lichen planus preceding concomitant lichen planopilaris.

    PubMed

    Stoopler, Eric T; Alfaris, Sausan; Alomar, Dalal; Alawi, Faizan

    2016-09-01

    Lichen planus (LP) is an immune-mediated mucocutaneous disorder with a wide array of clinical presentations. Oral lichen planus (OLP) is characterized clinically by striae, desquamation, and/or ulceration. Lichen planopilaris (LPP), a variant of LP, affects the scalp, resulting in perifollicular erythema and scarring of cutaneous surfaces accompanied by hair loss. The association between OLP and LPP has been reported previously with scant information on concomitant or sequential disease presentation. We describe a patient with concomitant OLP and LPP, and to the best of our knowledge, this is the first report on OLP preceding the onset of LPP. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Symptoms of schizotypy precede cannabis use.

    PubMed

    Schiffman, Jason; Nakamura, Brad; Earleywine, Mitchell; LaBrie, Joseph

    2005-03-30

    The current investigation uses a large non-clinical sample of undergraduate college students (N=189) to investigate schizotypal traits among cannabis and non-cannabis users, as well as the temporal order of the onset of these traits and cannabis use. Findings suggest that regular cannabis users are significantly more prone to cognitive and perceptual distortions as well as disorganization, but not interpersonal deficits, than non-regular users and those who have never used. Additionally, the onset of schizotypal symptoms generally precedes the onset of cannabis use. The findings do not support a causal link between cannabis use and schizotypal traits.

  15. Yeast PAH1-encoded phosphatidate phosphatase controls the expression of CHO1-encoded phosphatidylserine synthase for membrane phospholipid synthesis.

    PubMed

    Han, Gil-Soo; Carman, George M

    2017-08-11

    The PAH1-encoded phosphatidate phosphatase (PAP), which catalyzes the committed step for the synthesis of triacylglycerol in Saccharomyces cerevisiae, exerts a negative regulatory effect on the level of phosphatidate used for the de novo synthesis of membrane phospholipids. This raises the question whether PAP thereby affects the expression and activity of enzymes involved in phospholipid synthesis. Here, we examined the PAP-mediated regulation of CHO1-encoded phosphatidylserine synthase (PSS), which catalyzes the committed step for the synthesis of major phospholipids via the CDP-diacylglycerol pathway. The lack of PAP in the pah1Δ mutant highly elevated PSS activity, exhibiting a growth-dependent up-regulation from the exponential to the stationary phase of growth. Immunoblot analysis showed that the elevation of PSS activity results from an increase in the level of the enzyme encoded by CHO1 Truncation analysis and site-directed mutagenesis of the CHO1 promoter indicated that Cho1 expression in the pah1Δ mutant is induced through the inositol-sensitive upstream activation sequence (UASINO), a cis-acting element for the phosphatidate-controlled Henry (Ino2-Ino4/Opi1) regulatory circuit. The abrogation of Cho1 induction and PSS activity by a CHO1 UASINO mutation suppressed pah1Δ effects on lipid synthesis, nuclear/endoplasmic reticulum membrane morphology, and lipid droplet formation, but not on growth at elevated temperature. Loss of the DGK1-encoded diacylglycerol kinase, which converts diacylglycerol to phosphatidate, partially suppressed the pah1Δ-mediated induction of Cho1 and PSS activity. Collectively, these data showed that PAP activity controls the expression of PSS for membrane phospholipid synthesis. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Activation of inositol trisphosphate-sensitive Ca2+ channels of sarcoplasmic reticulum from frog skeletal muscle.

    PubMed Central

    Suárez-Isla, B A; Alcayaga, C; Marengo, J J; Bull, R

    1991-01-01

    1. The modulation by Ca2+ of the activation by inositol 1,4,5-trisphosphate (IP3) of Ca2+ channels present in native sarcoplasmic reticulum membranes from frog skeletal muscle was studied after channel incorporation into planar phospholipid bilayers in the presence of Ca2+ or Ba2+ as current carrier species. 2. Channel activity expressed as fractional open time (Po) was low (less than or equal to 0.15) in the presence of varying free Ca2+ concentrations bathing the myoplasmic face of the channel (cis side), and did not increase significantly between 0.01 and 30 microM-Ca2+. 3. Channel activation mediated by IP3 could be elicited from free Ca2+ levels similar to those of resting skeletal muscle (about 0.1 microM) and was found to be strongly regulated by the free Ca2+ concentration present at the myoplasmic moiety of the channel. 4. Channel activation by 10 microM-IP3 depended on the Ca2+ concentration on the cis side. Po reached a maximum between pCa 7.0 and 6.0, but decreased at higher concentrations of free Ca2+. Thus, Ca2+ exerted a modulatory influence on IP3-mediated activation in a concentration range where the channel was insensitive to Ca2+. 5. The results indicate that Ca2+ ions act as modulators of IP3 efficacy to open the channel. This could arise from an interaction of Ca2+ with the channel gating mechanism or with the agonist binding site. PMID:1667801

  17. Inositol hexaphosphate inhibits tumor growth, vascularity, and metabolism in TRAMP mice: a multiparametric magnetic resonance study.

    PubMed

    Raina, Komal; Ravichandran, Kameswaran; Rajamanickam, Subapriya; Huber, Kendra M; Serkova, Natalie J; Agarwal, Rajesh

    2013-01-01

    Herein, employing anatomical and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI), we evaluated noninvasively, the in vivo, chemopreventive efficacy of inositol hexaphosphate (IP6), a major constituent of high-fiber diets, against prostate tumor growth and progression in transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Male TRAMP mice, beginning at 4 weeks of age, were fed with 1%, 2%, or 4% (w/v) IP6 in drinking water or only drinking water till 28 weeks of age and monitored using MRI over the course of study. Longitudinal assessment of prostate volumes by conventional MRI and tumor vascularity by gadolinium-based DCE-MRI showed a profound reduction in tumor size, partly due to antiangiogenic effects by IP6 treatment. As potential mechanisms of IP6 efficacy, decrease in the expression of glucose transporter GLUT-4 protein together with an increase in levels of phospho-AMP-activated kinase (AMPK(Th172)) were observed in prostate tissues of mice from IP6 fed-groups, suggesting that IP6 is interfering with the metabolic events occurring in TRAMP prostate. Investigative metabolomics study using quantitative high-resolution (1)H-NMR on prostate tissue extracts showed that IP6 significantly decreased glucose metabolism and membrane phospholipid synthesis, in addition to causing an increase in myoinositol levels in the prostate. Together, these findings show that oral IP6 supplement blocks growth and angiogenesis of prostate cancer in the TRAMP model in conjunction with metabolic events involved in tumor sustenance. This results in energy deprivation within the tumor, suggesting a practical and translational potential of IP6 treatment in suppressing growth and progression of prostate cancer in humans. ©2012 AACR.

  18. Identification of inhibitors of inositol 5-phosphatases through multiple screening strategies.

    PubMed

    Pirruccello, Michelle; Nandez, Ramiro; Idevall-Hagren, Olof; Alcazar-Roman, Abel; Abriola, Laura; Berwick, Shana Alexandra; Lucast, Louise; Morel, Dayna; De Camilli, Pietro

    2014-06-20

    Phosphoinositides are low abundance membrane phospholipids that have key roles in signaling, membrane trafficking, and cytoskeletal dynamics in all cells. Until recently, strategies for robust and quantitative development of pharmacological tools for manipulating phosphoinositide levels have focused selectively on PI(3,4,5)P3 due to the importance of this lipid in growth factor signaling and cell proliferation. However, drugs that affect levels of other phosphoinositides have potential therapeutic applications and will be powerful research tools. Here, we describe methodology for the high-throughput screening of small molecule modulators of the inositol 5-phosphatases, which dephosphorylate PI(4,5)P2 (the precursor for PI(3,4,5)P3) and PI(3,4,5)P3). We developed three complementary in vitro activity assays, tested hit compounds on a panel of 5-phosphatases, and monitored efficacy toward various substrates. Two prominent chemical scaffolds were identified with high nanomolar/low micromolar activity, with one class showing inhibitory activity toward all 5-phosphatases tested and the other selective activity toward OCRL and INPP5B, which are closely related to each other. One highly soluble OCRL/INPP5B-specific inhibitor shows a direct interaction with the catalytic domain of INPP5B. The efficacy of this compound in living cells was validated through its property to enhance actin nucleation at the cell cortex, a PI(4,5)P2 dependent process, and to inhibit PI(4,5)P2 dephosphorylation by OCRL (both overexpressed and endogenous enzyme). The assays and screening strategies described here are applicable to other phosphoinositide-metabolizing enzymes, at least several of which have major clinical relevance. Most importantly, this study identifies the first OCRL/INPP5B specific inhibitor and provides a platform for the design of more potent inhibitors of this family of enzymes.

  19. Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Marto, J A; White, F M; Seldomridge, S; Marshall, A G

    1995-11-01

    Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode.

  20. [Psychosocial stress preceding drug-related deaths].

    PubMed

    Kraus, L; Müller-Kalthoff, T

    2002-10-01

    This article analyses drug-related deaths in the German Federal States of Bavaria (Munich, Nuremberg and Augsburg counties) during 1999 and Baden-Wurttemberg (Stuttgart and Mannheim counties) during 1999 and in the first half of 2000. The persons who had been in contact with drug care services were studied for psychosocial stress preceding drug-related deaths. Epidemiological data from different sources (police, relatives, counselling centres, detoxification clinics, therapy and substitution treatment) were collated to estimate factors of psychosocial stress preceding drug deaths. The results in both Laender indicate high prevalence rates of a history of at least one non-fatal overdose (approx. 50%) or a suicide attempt (approx. 35%). More than 40% of the deceased had been suffering from at least one additional mental disorder, in most cases from depression. At least one critical life event (in most cases, a relapse) or a period of abstinence (i.e., due to imprisonment, therapy or detoxification) during the past three months before death was reported for more than half of the addicts. The results were discussed in the light of data on opiate users and the general population. Improved specialist training of therapeutic and medical workers as well as of any other co-operating professionals is considered a necessary prerequisite for an early detection of risk factors.

  1. Inositol lipid phosphatases in membrane trafficking and human disease.

    PubMed

    Billcliff, Peter G; Lowe, Martin

    2014-07-15

    The specific interaction of phosphoinositides with proteins is critical for a plethora of cellular processes, including cytoskeleton remodelling, mitogenic signalling, ion channel regulation and membrane traffic. The spatiotemporal restriction of different phosphoinositide species helps to define compartments within the cell, and this is particularly important for membrane trafficking within both the secretory and endocytic pathways. Phosphoinositide homoeostasis is tightly regulated by a large number of inositol kinases and phosphatases, which respectively phosphorylate and dephosphorylate distinct phosphoinositide species. Many of these enzymes have been implicated in regulating membrane trafficking and, accordingly, their dysregulation has been linked to a number of human diseases. In the present review, we focus on the inositol phosphatases, concentrating on their roles in membrane trafficking and the human diseases with which they have been associated.

  2. Protection against cancer by dietary IP6 and inositol.

    PubMed

    Vucenik, Ivana; Shamsuddin, AbulKalam M

    2006-01-01

    Inositol hexaphosphate (IP(6)) is a naturally occurring polyphosphorylated carbohydrate, abundantly present in many plant sources and in certain high-fiber diets, such as cereals and legumes. In addition to being found in plants, IP(6) is contained in almost all mammalian cells, although in much smaller amounts, where it is important in regulating vital cellular functions such as signal transduction, cell proliferation, and differentiation. For a long time IP(6) has been recognized as a natural antioxidant. Recently IP(6) has received much attention for its role in cancer prevention and control of experimental tumor growth, progression, and metastasis. In addition, IP(6) possesses other significant benefits for human health, such as the ability to enhance immune system, prevent pathological calcification and kidney stone formation, lower elevated serum cholesterol, and reduce pathological platelet activity. In this review we show the efficacy and discuss some of the molecular mechanisms that govern the action of this dietary agent. Exogenously administered IP(6) is rapidly taken up into cells and dephosphorylated to lower inositol phosphates, which further affect signal transduction pathways resulting in cell cycle arrest. A striking anticancer action of IP(6) was demonstrated in different experimental models. In addition to reducing cell proliferation, IP(6) also induces differentiation of malignant cells. Enhanced immunity and antioxidant properties also contribute to tumor cell destruction. Preliminary studies in humans show that IP(6) and inositol, the precursor molecule of IP(6), appear to enhance the anticancer effect of conventional chemotherapy, control cancer metastases, and improve quality of life. Because it is abundantly present in regular diet, efficiently absorbed from the gastrointestinal tract, and safe, IP(6) + inositol holds great promise in our strategies for cancer prevention and therapy. There is clearly enough evidence to justify the

  3. Membrane interaction and functional plasticity of inositol polyphosphate 5-phosphatases.

    PubMed

    Braun, Werner; Schein, Catherine H

    2014-05-06

    In this issue of Structure, Trésaugues and colleagues determined the interaction of membrane-bound phosphoinositides with three clinically significant human inositol polyphosphate 5-phosphatases (I5Ps). A comparison to the structures determined with soluble substrates revealed differences in the binding mode and suggested how the I5Ps and apurinic endonuclease (APE1) activities evolved from the same metal-binding active center.

  4. Myoinositol and D-Chiro Inositol in Improving Insulin Resistance in Obese Male Children: Preliminary Data

    PubMed Central

    Andreassi, Alice; Salvioni, Michela; Pelliccione, Fiore; Mantellassi, Gianna; Banderali, Giuseppe

    2016-01-01

    Myoinositol and D-chiro inositol, which are inositol isomers, have been shown to possess insulin-mimetic properties and to improve insulin resistance, especially in women with polycystic ovary syndrome. However, it has not been determined if this relationship exists also in children. Based on these previous findings, we hypothesized that inositol could be effective in improving insulin sensitivity in children with insulin resistance. To evaluate this hypothesis, we administered both inositol formulations before carrying out an oral glucose tolerance test (OGTT) in a group of obese insulin-resistant male children with high basal insulin levels and compared the values obtained with an OGTT previously conducted without inositol, in the same group, with unchanged BMI. Our results confirm that myoinositol and D-chiro inositol acutely reduce insulin increase after glucose intake mainly in children with high basal insulin level. PMID:27882052

  5. Inhibition by Ca2+ of inositol trisphosphate-mediated Ca2+ liberation: a possible mechanism for oscillatory release of Ca2+.

    PubMed Central

    Parker, I; Ivorra, I

    1990-01-01

    Light-flash photolysis of caged inositol 1,4,5-trisphosphate (InsP3) was used to generate reproducible transients of free InsP3 in Xenopus oocytes, and the resulting liberation of Ca2+ from intracellular stores was monitored by recording Ca2+-activated membrane currents and by use of the fluorescent Ca2+ indicator fluo-3. InsP3-mediated Ca2+ release was inhibited by elevating the intracellular free Ca2+ level, either by microinjecting Ca2+ into the cell or by applying conditioning light flashes to liberate Ca2+. This inhibition followed a slow time course, being maximal after about 2 s and subsequently declining over several seconds. Negative feedback of Ca2+ ions on InsP3-mediated Ca2+ liberation may explain the oscillatory release of Ca2+ seen during activation of inositol phospholipid signaling in the oocyte, and the time course of the inhibition is consistent with the period of the oscillations. PMID:2296584

  6. A femtomole-sensitivity mass assay for inositol hexakisphosphate.

    PubMed

    Letcher, Andrew J; Schell, Michael J; Irvine, Robin F

    2010-01-01

    Inositol hexakisphosphate (InsP(6)) is an important component of cells, and its mass levels are usually assayed by either (a) equilibrium labelling of cell cultures with radiolabelled inositol or (b) by a variety of mass assays of differing sensitivities and ambiguities. Here, we describe a mass assay for InsP(6) that is based on phosphorylating InsP(6) with [(32)P]-ATP to 5-(PP)InsP(5) using a recombinant Giardia InsP(6) kinase and quantification of the radiolabelled 5-[(32)P](PP)InsP(5) product by anion exchange HPLC with an internal [(3)H]-(PP)InsP(5) standard. Interference with the enzyme reaction by other factors in the tissue extract is corrected for by assay of identical aliquots of tissue spiked with known amounts of InsP(6). This assay only measures InsP(6) (and not other inositol phosphates), and although it is simple in principle and requires no dedicated or specialised equipment, it is quite time-consuming. But the assay is unambiguous and is capable of quantifying accurately as little as 10 fmol of InsP(6) in a cell extract.

  7. Structural Studies and Protein Engineering of Inositol Phosphate Multikinase*

    PubMed Central

    Endo-Streeter, Stuart; Tsui, Man-Kin Marco; Odom, Audrey R.; Block, Jeremy; York, John D.

    2012-01-01

    Inositol phosphates (IPs) regulate vital processes in eukaryotes, and their production downstream of phospholipase C activation is controlled through a network of evolutionarily conserved kinases and phosphatases. Inositol phosphate multikinase (IPMK, also called Ipk2 and Arg82) accounts for phosphorylation of IP3 to IP5, as well as production of several other IP molecules. Here, we report the structure of Arabidopsis thaliana IPMKα at 2.9 Å and find it is similar to the yeast homolog Ipk2, despite 17% sequence identity, as well as the active site architecture of human IP3 3-kinase. Structural comparison and substrate modeling were used to identify a putative basis for IPMK selectivity. To test this model, we re-engineered binding site residues predicted to have restricted substrate specificity. Using steady-state kinetics and in vivo metabolic labeling studies in modified yeast strains, we observed that K117W and K117W:K121W mutants exhibited nearly normal 6-kinase function but harbored significantly reduced 3-kinase activity. These mutants complemented conditional nutritional growth defects observed in ipmk null yeast and, remarkably, suppressed lethality observed in ipmk null flies. Our data are consistent with the hypothesis that IPMK 6-kinase activity and production of Ins(1,4,5,6)P4 are critical for cellular signaling. Overall, our studies provide new insights into the structure and function of IPMK and utilize a synthetic biological approach to redesign inositol phosphate signaling pathways. PMID:22896696

  8. Intracellular delivery of phosphoinositides and inositol phosphates using polyamine carriers

    PubMed Central

    Ozaki, Shoichiro; DeWald, Daryll B.; Shope, Joseph C.; Chen, Jian; Prestwich, Glenn D.

    2000-01-01

    Phosphoinositide signaling regulates events in endocytosis and exocytosis, vesicular trafficking of proteins, transduction of extracellular signals, remodeling of the actin cytoskeleton, regulation of calcium flux, and apoptosis. Obtaining mechanistic insights in living cells is impeded by the membrane impermeability of these anionic lipids. We describe a carrier system for intracellular delivery of phosphoinositide polyphosphates (PIPns) and fluorescently labeled PIPns into living cells, such that intracellular localization can be directly observed. Preincubation of PIPns or inositol phosphates with carrier polyamines produced complexes that entered mammalian, plant, yeast, bacterial, and protozoal cells in seconds to minutes via a nonendocytic mechanism. Time-dependent transit of both PIPns and the carrier to specific cytosolic and nuclear compartments was readily visualized by fluorescence microscopy. Platelet-derived growth factor treatment of NIH 3T3 fibroblasts containing carrier-delivered phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]-7-nitrobenz-2-oxa-1,3-diazole resulted in the redistribution of the fluorescent signal, suggesting that fluorescent PtdIns(4,5)P2 was a substrate for phospholipase C. We also observed a calcium flux in NIH 3T3 cells when complexes of carrier and PtdIns(4,5)P2 or inositol 1,4,5-trisphosphate were added extracellularly. This simple intracellular delivery system allows for the efficient translocation of biologically active PIPns, inositol phosphates, and their fluorescent derivatives into living cells in a physiologically relevant context. PMID:11005844

  9. Fish Oil Supplementation in Humans: Effects on Platelet Responses, Phospholipid Composition and Metabolism.

    NASA Astrophysics Data System (ADS)

    Skeaff, Clark Murray

    Platelets are believed to play a significant role in the development of occlusive vascular diseases. Epidemiological reports have correlated the high intake of marine foods, rich in omega3 fatty acids, with diminished platelet responses and a low incidence of arterial thrombosis and myocardial infarction. The activation of platelet responses is mediated by the accelerated metabolism of membrane phospholipid; therefore, it was of interest to examine, in human volunteers, the effect of a dietary fish oil concentrate (MaxEPA), enriched in omega 3 polyunsaturated fatty acids, on platelet aggregation and phospholipid composition/metabolism. For the complete separation of cellular phospholipids, a one-dimensional thin-layer chromatography system using silica-gel pre-coated glass plates was developed. The solvent system consisted of CHCl_3/CH_3OH/CH _3COOH/H_2O (50/37.5/3.5/2.0, by vol), required approximately 90-120 minutes for full phospholipid separation, and was highly reproducible even under conditions of variable humidity and temperature. The consumption of a fish oil concentrate (MaxEPA) for 6 weeks (3.6 g of 20:5omega 3 and 2.4 g of 22:6omega3 per day) diminished both the collagen- and platelet activating factor-induced maximum aggregation responses in washed human platelet suspensions by 50.1% and 27.2%, respectively, as compared to initial unsupplemented baseline responses. Thrombin -induced aggregation remained unchanged. Thrombin stimulation of intact human platelets produced a significant decrease in the mass of phosphatidylinositol in plasma membrane. In platelets pre-labelled with (2-^3H) glycerol and stimulated with either thrombin or low-dose collagen, the loss of (^3H) phosphatidylinositol did not differ between those subjects consuming olive oil or fish oil. Likewise, the thrombin-stimulated accumulation of diacylglycerol, an activator of protein kinase C, was unaffected by fish oil consumption. The ratio of collagen -induced increase in radioactivity

  10. PLA2-responsive and SPIO-loaded phospholipid micelles

    PubMed Central

    Gao, Qiang; Yan, Lesan; Chiorazzo, Michael; Delikatny, E. James; Tsourkas, Andrew; Cheng, Zhiliang

    2015-01-01

    A PLA2-responsive and superparamagnetic iron oxide (SPIO) nanoparticle-loaded phospholipid micelle was developed. The release of phospholipid-conjugated dye from these micelles was triggered due to phospholipid degradation by phospholipase A2. High relaxivity of the encapsulated SPIO could enable non-invasive magnetic resonance imaging. PMID:26139589

  11. An evaluation of serum high density lipoproteins-phospholipids.

    PubMed

    Ide, H; Tsuji, M; Shimada, M; Kondo, T; Fujiya, S; Asanuma, Y; Agishi, Y

    1988-07-01

    Phospholipids in high density lipoproteins (HDL) is being used as a negative risk indicator of atherosclerosis. Phospholipids in HDL may not demonstrate the actual level of HDL-phospholipids when determined by the precipitation or ultracentrifugal methods, because HDL fractions contain very high density lipoproteins (VHDL) and albumin. In the present study, the true level of phospholipids in HDL was estimated using high performance liquid chromatography (HPLC), and it was compared with the level of phospholipids in HDL determined by the precipitation method. Sera from 18 healthy subjects were used as materials. In the HPLC method, the HDL fraction was extracted making sure that it contained no free albumin, which is albumin not bound to phospholipids. The HDL fraction was separated into subfractions. It was found that phospholipids in the VHDL fraction make a 20.2 +/- 7.3% (mean +/- S.D.) part of the total HDL-phospholipids. A large part of the VHDL fraction was constituted of albumin-bound phospholipids. A significant correlation was observed between HDL-phospholipids determined by the precipitation method, which contain albumin, and the actual HDL fraction phospholipids determined by HPLC, which do not contain VHDL (r = 0.903, p less than 0.01). These results suggest that HDL-phospholipids values determined by the precipitation method give useful clinical data.

  12. Myo-inositol products in polycystic ovary syndrome (PCOS) treatment: quality, labeling accuracy, and cost comparison.

    PubMed

    Papaleo, E; Molgora, M; Quaranta, L; Pellegrino, M; De Michele, F

    2011-02-01

    To evaluate the labeling accuracy of four myo-inositol products, designed for polycystic ovary syndrome (PCOS) treatment, available on the italian market and to perform a cost comparison based on myo-inositol content in milligrams for products analyzed. Four (4) myo-inositol products (3 sachet and 1 tablet formulations) were dissolved using water, and each sample was analyzed for myo-inositol content using a high-performance liquid chromatography (HPLC) method with index refraction detector. The amount of myo-inositol per purchased product was then divided into its purchase price in order to make cost comparisons between the products based on a 2 and 4 g/day dose. A significant difference in the myo-inositol content, compared with the labeling was found for the products. Only 1 product contained more than 95% of the myo-inositol content claimed on the label, and there was a product with less than 75% of the labeling amount. Based on a 2-g myo-inositol per day dose, the cost of a 30-day supply ranged from Euro 20,77 and Euro 71,86, after correction by actual amount of myo-inositol. There is a lack of conformity between declared and actual amount of myo-inositol among the products tested and the majority of the products contained less than 95% of labeled amounts. There should be a better control in the manufacturing process in order to ensure more quality and accuracy. Nowadays consumers cannot trust myo-inositol product labels to represent the product's content accurately or that product pricing is a reflection of myo-inositol content.

  13. Phospholipids of New Zealand Edible Brown Algae.

    PubMed

    Vyssotski, Mikhail; Lagutin, Kirill; MacKenzie, Andrew; Mitchell, Kevin; Scott, Dawn

    2017-07-01

    Edible brown algae have attracted interest as a source of beneficial allenic carotenoid fucoxanthin, and glyco- and phospholipids enriched in polyunsaturated fatty acids. Unlike green algae, brown algae contain no or little phosphatidylserine, possessing an unusual aminophospholipid, phosphatidyl-O-[N-(2-hydroxyethyl) glycine], PHEG, instead. When our routinely used technique of (31)P-NMR analysis of phospholipids was applied to the samples of edible New Zealand brown algae, a number of signals corresponding to unidentified phosphorus-containing compounds were observed in total lipids. NI (negative ion) ESI QToF MS spectra confirmed the presence of more familiar phospholipids, and also suggested the presence of PHEG or its isomers. The structure of PHEG was confirmed by comparison with a synthetic standard. An unusual MS fragmentation pattern that was also observed prompted us to synthesise a number of possible candidates, and was found to follow that of phosphatidylhydroxyethyl methylcarbamate, likely an extraction artefact. An unexpected outcome was the finding of ceramidephosphoinositol that has not been reported previously as occurring in brown algae. An uncommon arsenic-containing phospholipid has also been observed and quantified, and its TLC behaviour studied, along with that of the newly synthesised lipids.

  14. Feruloyl Dioleoyglycerol Antioxidant Capacity in Phospholipid Vesicles

    USDA-ARS?s Scientific Manuscript database

    Ferulic acid and its esters are known to be effective antioxidants. Feruloyl dioleoylglycerol was assessed for its ability to serve as an antioxidant in model membrane phospholipid vesicles. The molecule was incorporated into single-lamellar vesicles of 1,2-dioleoyl-sn-glycero-3-phosphocholine at ...

  15. Inositols and methylinositols in sea buckthorn (Hippophaë rhamnoides) berries.

    PubMed

    Kallio, Heikki; Lassila, Marika; Järvenpää, Eila; Haraldsson, Gudmundur G; Jonsdottir, Sigridur; Yang, Baoru

    2009-05-15

    Sea buckthorn (Hippophaë rhamnoides L.) berries, especially of ssp. sinensis, contain significant quantities of an unknown, water-soluble compound, evidently a cyclitol derivative. The compound was isolated by HPLC and analyzed by GC-MS [trimethylsilyl (TMS) derivative, selected ion monitoring (SIM) and total ion chromatogram (TIC) analyses], by (1)H and (13)C NMR and by optical activity measurements. The results together with analyses of reference compound verified the unambiguous structure (-)-2-O-methyl-L-chiro-inositol (L-quebrachitol). In addition, chiro-inositol and myo-inositol existing in trace amounts were identified based on reference compounds, chromatographic data and mass spectra of the TMS derivatives. Methyl-myo-inositol was tentatively identified based on chromatography and mass spectrometry. Inositols and methyl inositols are bioactive compounds essential for regulating physiological processes of plants and humans. To our knowledge, this is the first report on the presence of chiro-inositol and myo-inositol in sea buckthorn and L-quebrachitol in edible berries. The identification of the inositols and l-quebrachitol in sea buckthorn may bring new insights into the sensory properties and also mechanisms behind the health effects of the berry.

  16. [Wide QRS tachycardia preceded by pacemaker spikes].

    PubMed

    Romero, M; Aranda, A; Gómez, F J; Jurado, A

    2014-04-01

    The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral.

  17. Blood clotting reactions on nanoscale phospholipid bilayers.

    PubMed

    Morrissey, James H; Pureza, Vincent; Davis-Harrison, Rebecca L; Sligar, Stephen G; Ohkubo, Y Zenmei; Tajkhorshid, Emad

    2008-01-01

    Blood clotting reactions, such as those catalyzed by the tissue factor:factor VIIa complex (TF:FVIIa), assemble on membrane surfaces containing anionic phospholipids such as phosphatidylserine (PS). In fact, membrane binding is critical for the function of most of the steps in the blood clotting cascade. In spite of this, our understanding of how the membrane contributes to catalysis, or even how these proteins interact with phospholipids, is incomplete. Making matters more complicated, membranes containing mixtures of PS and neutral phospholipids are known to spontaneously form PS-rich membrane microdomains in the presence of plasma concentrations of calcium ions, and it is likely that blood-clotting proteases such as TF:FVIIa partition into these PS-rich microdomains. Unfortunately, little is known about how membrane microdomain composition influences the activity of blood-clotting proteases, which is typically not under experimental control even in "simple" model membranes. Our laboratories have developed and applied new technologies for studying membrane proteins to gain insights into how blood-clotting protease-cofactor pairs assemble and function on membrane surfaces. This includes using a novel, nanoscale bilayer system (Nanodiscs) that permits assembling blood-clotting protease-cofactor pairs on stable bilayers containing from 65 to 250 phospholipid molecules per leaflet. We have used this system to investigate how local (nanometer-scale) changes in phospholipid bilayer composition modulate TF:FVIIa activity. We have also used detailed molecular-dynamics simulations of nanoscale bilayers to provide atomic-scale predictions of how the membrane-binding domain of factor VIIa interacts with PS in membranes.

  18. Blood clotting reactions on nanoscale phospholipid bilayers

    PubMed Central

    Morrissey, James H.; Pureza, Vincent; Davis-Harrison, Rebecca L.; Sligar, Stephen G.; Ohkubo, Y. Zenmei; Tajkhorshid, Emad

    2010-01-01

    Blood clotting reactions, such as those catalyzed by the tissue factor/factor VIIa complex (TF:VIIa), assemble on membrane surfaces containing anionic phospholipids such as phosphatidylserine (PS). In fact, membrane binding is critical for the function of most of the steps in the blood clotting cascade. In spite of this, our understanding of how the membrane contributes to catalysis, or even how these proteins interact with phospholipids, is incomplete. Making matters more complicated, membranes containing mixtures of PS and neutral phospholipids are known to spontaneously form PS-rich membrane microdomains in the presence of plasma concentrations of calcium ions, and it is likely that blood clotting proteases such as TF:VIIa partition into these PS-rich microdomains. Unfortunately, little is known about how membrane microdomain composition influences the activity of blood clotting proteases, which is typically not under experimental control even in “simple” model membranes. Our laboratories have developed and applied new technologies for studying membrane proteins to gain insights into how blood clotting protease-cofactor pairs assemble and function on membrane surfaces. This includes using a novel, nanoscale bilayer system (Nanodiscs) that permits assembling blood clotting protease-cofactor pairs on stable bilayers containing from 65 to 250 phospholipid molecules per leaflet. We have used this system to investigate how local (nanometer-scale) changes in phospholipid bilayer composition modulate TF:VIIa activity. We have also used detailed molecular dynamics simulations of nanoscale bilayers to provide atomic-scale predictions of how the membrane-binding domain of factor VIIa interacts with PS in membranes. PMID:18691494

  19. Synthesis of mannosylglucosaminylinositol phospholipids in normal but not paroxysmal nocturnal hemoglobinuria cells.

    PubMed

    Hirose, S; Ravi, L; Prince, G M; Rosenfeld, M G; Silber, R; Andresen, S W; Hazra, S V; Medof, M E

    1992-07-01

    To identify mannosyl (Man)-containing intermediates of the human glycoinositol phospholipid (GPI) anchor pathway and examine their expression in paroxysmal nocturnal hemoglobinuria (PNH), mannolipid products deriving from in vitro guanosine diphosphate [3H]Man labeling of HeLa cell microsomes were characterized. The defined GPI species were correlated with products deriving from in vivo [3H]Man labeling of normal and (GPI-anchor defective) affected leukocytes. In vitro analyses in HeLa cells showed dolichol-phosphoryl (Dol-P)-[3H]Man and a spectrum of [3H]Man lipids exhibiting TLC mobilities approximating those of Trypanosoma brucei (Tryp) GPI precursors. Iatrobead HPLC separations and partial characterizations of the major isolated [3H]Man species (designated H1-H8) showed that all but H1 (Dol-P-Man) were sensitive to HNO2 deamination and serum GPI-specific phospholipase D digestion but were resistant to phosphatidylinositol-specific phospholipase C digestion unless previously deacylated with mild alkali. [3H]Man label in H3, H4, and H6 but not in H5 or H7 was efficiently released into the aqueous phase by jack bean alpha-mannosidase digestion. BioGel P-4 and AX-5 sizing of the dephosphorylated core glycan fragments of H6 and H7 gave values that coincided precisely with the corresponding glycan fragments from the fully assembled Tryp anchor donor A' (P2). Affected leukocytes from four patients with PNH supported formation of GlcNAc- and GlcN-PI but all failed to express H6 and H7 as well as H8 and two showed complete absence of earlier Man-containing intermediates. These findings argue that human intracellular GPI mannolipids are built on acylated inositol phospholipids, that H6 and H7 contain differentially phosphoethanolamine-substituted Man3-GlcN-inositol cores, and that PNH cells are defective in conversion of GlcN-PI into these more mature mannolipid structures.

  20. Cerebral Hypoperfusion Precedes Nausea During Centrifugation

    NASA Technical Reports Server (NTRS)

    Serrador, Jorge M.; Schlegel, Todd T.; Black, F. Owen; Wood, Scott J.

    2004-01-01

    Nausea and motion sickness are important operational concerns for aviators and astronauts. Understanding underlying mechanisms associated with motion sickness may lead to new treatments. The goal of this work was to determine if cerebral blood flow changes precede the development of nausea in motion sick susceptible subjects. Cerebral flow velocity in the middle cerebral artery (transcranial Doppler), blood pressure (Finapres) and end-tidal CO2 were measured while subjects were rotated on a centrifuge (250 degrees/sec). Following 5 min of rotation, subjects were translated 0.504 m off-center, creating a +lGx centripetal acceleration in the nasal-occipital plane. Ten subjects completed the protocol without symptoms while 5 developed nausea (4 while 6ff-center and 1 while rotating on-center). Prior to nausea, subjects had significant increases in blood pressure (+13plus or minus 3 mmHg, P less than 0.05) and cerebrovascular resistance (+46 plus or minus 17%, P less than 0.05) and decreases in cerebral flow velocity both in the second (-13 plus or minus 4%) and last minute (-22 plus or minus 5%) before symptoms (P less than 0.05). In comparison, controls demonstrated no change in blood pressure or cerebrovascular resistance in the last minute of off-center rotation and only a 7 plus or minus 2% decrease in cerebral flow velocity. All subjects had significant hypocapnia (-3.8 plus or minus 0.4 mmHg, P less than 0.05), however this hypocapnia could not fully explain the cerebral hypoperfusion associated with the development of nausea. These data indicate that reductions in cerebral blood flow precede the development of nausea. Further work is necessary to determine what role cerebral hypoperfusion plays in motion sickness and whether cerebral hypoperfusion can be used to predict the development of nausea in susceptible individuals.

  1. Cochlear contributions to the precedence effect.

    PubMed

    Verhulst, Sarah; Bianchi, Federica; Dau, Torsten

    2013-01-01

    Normal-hearing individuals have sharply tuned auditory filters, and consequently their basilar-membrane (BM) impulse responses (IRs) have durations of several ms at frequencies in the range from 0 to 5 kHz. When presenting clicks that are several ms apart, the BM IRs to the individual clicks will overlap in time, giving rise to complex interactions that have not been fully understood in the human cochlea. The perceptual consequences of these BM IR interactions are of interest as lead-lag click pairs are often used to study localization and the precedence effect. The present study aimed at characterizing perceptual consequences of BM IR interactions in individual listeners based on click-evoked otoacoustic emissions (CEOAEs) and auditory brainstem responses (ABRs). Lag suppression, denoting the level difference between the CEOAE or wave-V response amplitude evoked by the first and the second clicks, was observed for inter-click intervals (ICIs) between 1 and 4 ms. Behavioral correlates of lag suppression were obtained for the same individuals by investigating the percept of the lead-lag click pairs presented either monaurally or binaurally. The click pairs were shown to give rise to fusion (i.e., the inability to hear out the second click in a lead-lag click pair), regardless of monaural or binaural presentation. In both cases, the ICI range where the percept was a fused image correlated well with the ICI range for which monaural lag suppression occurred in the CEOAE and ABR (i.e., for ICIs below 4.3 ms). Furthermore, the lag suppression observed in the wave-V amplitudes to binaural stimulation did not show additional contributions to the lag suppression obtained monaurally, suggesting that peripheral lag suppression up to the level of the brainstem is dominant in the perception of the precedence effect.

  2. Comparative genomics of pneumocystis species suggests the absence of genes for myo-inositol synthesis and reliance on inositol transport and metabolism.

    PubMed

    Porollo, Aleksey; Sesterhenn, Thomas M; Collins, Margaret S; Welge, Jeffrey A; Cushion, Melanie T

    2014-11-04

    In the context of deciphering the metabolic strategies of the obligate pathogenic fungi in the genus Pneumocystis, the genomes of three species (P. carinii, P. murina, and P. jirovecii) were compared among themselves and with the free-living, phylogenetically related fission yeast (Schizosaccharomyces pombe). The underrepresentation of amino acid metabolism pathways compared to those in S. pombe, as well as the incomplete steroid biosynthesis pathway, were confirmed for P. carinii and P. jirovecii and extended to P. murina. All three Pneumocystis species showed overrepresentation of the inositol phosphate metabolism pathway compared to that in the fission yeast. In addition to those known in S. pombe, four genes, encoding inositol-polyphosphate multikinase (EC 2.7.1.151), inositol-pentakisphosphate 2-kinase (EC 2.7.1.158), phosphoinositide 5-phosphatase (EC 3.1.3.36), and inositol-1,4-bisphosphate 1-phosphatase (EC 3.1.3.57), were identified in the two rodent Pneumocystis genomes, P. carinii and P. murina. The P. jirovecii genome appeared to contain three of these genes but lacked phosphoinositide 5-phosphatase. Notably, two genes encoding enzymes essential for myo-inositol synthesis, inositol-1-phosphate synthase (INO1) and inositol monophosphatase (INM1), were absent from all three genomes, suggesting that Pneumocystis species are inositol auxotrophs. In keeping with the need to acquire exogenous inositol, two genes with products homologous to fungal inositol transporters, ITR1 and ITR2, were identified in P. carinii and P. murina, while P. jirovecii contained only the ITR1 homolog. The ITR and inositol metabolism genes in P. murina and P. carinii were expressed during fulminant infection as determined by reverse transcriptase real-time PCR of cDNA from infected lung tissue. Supplementation of in vitro culture with inositol yielded significant improvement of the viability of P. carinii for days 7 through 14. Microbes in the genus Pneumocystis are obligate

  3. Results from the International Consensus Conference on Myo-inositol and d-chiro-inositol in Obstetrics and Gynecology: the link between metabolic syndrome and PCOS.

    PubMed

    Facchinetti, Fabio; Bizzarri, Mariano; Benvenga, Salvatore; D'Anna, Rosario; Lanzone, Antonio; Soulage, Christophe; Di Renzo, Gian Carlo; Hod, Moshe; Cavalli, Pietro; Chiu, Tony T; Kamenov, Zdravko A; Bevilacqua, Arturo; Carlomagno, Gianfranco; Gerli, Sandro; Oliva, Mario Montanino; Devroey, Paul

    2015-12-01

    In recent years, interest has been focused to the study of the two major inositol stereoisomers: myo-inositol (MI) and d-chiro-inositol (DCI), because of their involvement, as second messengers of insulin, in several insulin-dependent processes, such as metabolic syndrome and polycystic ovary syndrome. Although these molecules have different functions, very often their roles have been confused, while the meaning of several observations still needs to be interpreted under a more rigorous physiological framework. With the aim of clarifying this issue, the 2013 International Consensus Conference on MI and DCI in Obstetrics and Gynecology identified opinion leaders in all fields related to this area of research. They examined seminal experimental papers and randomized clinical trials reporting the role and the use of inositol(s) in clinical practice. The main topics were the relation between inositol(s) and metabolic syndrome, polycystic ovary syndrome (with a focus on both metabolic and reproductive aspects), congenital anomalies, gestational diabetes. Clinical trials demonstrated that inositol(s) supplementation could fruitfully affect different pathophysiological aspects of disorders pertaining Obstetrics and Gynecology. The treatment of PCOS women as well as the prevention of GDM seem those clinical conditions which take more advantages from MI supplementation, when used at a dose of 2g twice/day. The clinical experience with MI is largely superior to the one with DCI. However, the existence of tissue-specific ratios, namely in the ovary, has prompted researchers to recently develop a treatment based on both molecules in the proportion of 40 (MI) to 1 (DCI).

  4. Comparative Genomics of Pneumocystis Species Suggests the Absence of Genes for myo-Inositol Synthesis and Reliance on Inositol Transport and Metabolism

    PubMed Central

    Sesterhenn, Thomas M.; Collins, Margaret S.; Welge, Jeffrey A.

    2014-01-01

    ABSTRACT In the context of deciphering the metabolic strategies of the obligate pathogenic fungi in the genus Pneumocystis, the genomes of three species (P. carinii, P. murina, and P. jirovecii) were compared among themselves and with the free-living, phylogenetically related fission yeast (Schizosaccharomyces pombe). The underrepresentation of amino acid metabolism pathways compared to those in S. pombe, as well as the incomplete steroid biosynthesis pathway, were confirmed for P. carinii and P. jirovecii and extended to P. murina. All three Pneumocystis species showed overrepresentation of the inositol phosphate metabolism pathway compared to that in the fission yeast. In addition to those known in S. pombe, four genes, encoding inositol-polyphosphate multikinase (EC 2.7.1.151), inositol-pentakisphosphate 2-kinase (EC 2.7.1.158), phosphoinositide 5-phosphatase (EC 3.1.3.36), and inositol-1,4-bisphosphate 1-phosphatase (EC 3.1.3.57), were identified in the two rodent Pneumocystis genomes, P. carinii and P. murina. The P. jirovecii genome appeared to contain three of these genes but lacked phosphoinositide 5-phosphatase. Notably, two genes encoding enzymes essential for myo-inositol synthesis, inositol-1-phosphate synthase (INO1) and inositol monophosphatase (INM1), were absent from all three genomes, suggesting that Pneumocystis species are inositol auxotrophs. In keeping with the need to acquire exogenous inositol, two genes with products homologous to fungal inositol transporters, ITR1 and ITR2, were identified in P. carinii and P. murina, while P. jirovecii contained only the ITR1 homolog. The ITR and inositol metabolism genes in P. murina and P. carinii were expressed during fulminant infection as determined by reverse transcriptase real-time PCR of cDNA from infected lung tissue. Supplementation of in vitro culture with inositol yielded significant improvement of the viability of P. carinii for days 7 through 14. PMID:25370490

  5. Metabolism of myo-Inositol by Legionella pneumophila Promotes Infection of Amoebae and Macrophages

    PubMed Central

    Manske, Christian; Schell, Ursula

    2016-01-01

    ABSTRACT Legionella pneumophila is a natural parasite of environmental amoebae and the causative agent of a severe pneumonia termed Legionnaires' disease. The facultative intracellular pathogen employs a bipartite metabolism, where the amino acid serine serves as the major energy supply, while glycerol and glucose are mainly utilized for anabolic processes. The L. pneumophila genome harbors the cluster lpg1653 to lpg1649 putatively involved in the metabolism of the abundant carbohydrate myo-inositol (here termed inositol). To assess inositol metabolism by L. pneumophila, we constructed defined mutant strains lacking lpg1653 or lpg1652, which are predicted to encode the inositol transporter IolT or the inositol-2-dehydrogenase IolG, respectively. The mutant strains were not impaired for growth in complex or defined minimal media, and inositol did not promote extracellular growth. However, upon coinfection of Acanthamoeba castellanii, the mutants were outcompeted by the parental strain, indicating that the intracellular inositol metabolism confers a fitness advantage to the pathogen. Indeed, inositol added to L. pneumophila-infected amoebae or macrophages promoted intracellular growth of the parental strain, but not of the ΔiolT or ΔiolG mutant, and growth stimulation by inositol was restored by complementation of the mutant strains. The expression of the Piol promoter and bacterial uptake of inositol required the alternative sigma factor RpoS, a key virulence regulator of L. pneumophila. Finally, the parental strain and ΔiolG mutant bacteria but not the ΔiolT mutant strain accumulated [U-14C6]inositol, indicating that IolT indeed functions as an inositol transporter. Taken together, intracellular L. pneumophila metabolizes inositol through the iol gene products, thus promoting the growth and virulence of the pathogen. IMPORTANCE The environmental bacterium Legionella pneumophila is the causative agent of a severe pneumonia termed Legionnaires' disease. The

  6. Quantitative imaging of inositol distribution in yeast using multi-isotope imaging mass spectrometry (MIMS).

    PubMed

    Saiardi, A; Guillermier, C; Loss, O; Poczatek, J C; Lechene, C

    2014-11-01

    Despite the widely recognized importance of the several species of inositol polyphosphates in cell biology, inositol has not been successfully imaged and quantified inside cells using traditional spectrophotometry. Multi-isotope imaging mass spectrometry (MIMS) technology, however, has facilitated direct imaging and measurement of cellular inositol. After pulsing cells with inositol labeled with the stable isotope Carbon-13 ((13)C), the label was detected in subcellular volumes by MIMS. The tridimensional localization of (13)C within the cell illustrated cellular distribution and local accumulation of inositol. In parallel, we performed control experiments with (13)C-Glucose to compare a different (13)C distribution pattern. Because many functions recently attributed to inositol polyphosphates are localized in the nucleus, we analyzed its relative nuclear concentration. We engineered yeast with human thymidine permease and viral thymidine kinase, then fed them with (15)N-thymidine. This permitted direct analysis of the nuclear DNA through the detection of the (15)N isotopic signal. We found practically no co-localization between inositol signal ((13)C-isotope) and nuclear signal ((15)N-isotope). The (13)C-tag (inositol) accumulation was highest at the plasma membrane and in cytoplasmic domains. In time-course labeling experiments performed with wild type yeast (WT) or modified yeast unable to synthesize inositol from glucose (ino1Δ), the half-time of labeled inositol accumulation was ~1 hour in WT and longer in ino1Δ. These studies should serve as a template to study metabolism and physiological role of inositol using genetically modified yeasts.

  7. Amyloid plaque formation precedes dendritic spine loss.

    PubMed

    Bittner, Tobias; Burgold, Steffen; Dorostkar, Mario M; Fuhrmann, Martin; Wegenast-Braun, Bettina M; Schmidt, Boris; Kretzschmar, Hans; Herms, Jochen

    2012-12-01

    Amyloid-beta plaque deposition represents a major neuropathological hallmark of Alzheimer's disease. While numerous studies have described dendritic spine loss in proximity to plaques, much less is known about the kinetics of these processes. In particular, the question as to whether synapse loss precedes or follows plaque formation remains unanswered. To address this question, and to learn more about the underlying kinetics, we simultaneously imaged amyloid plaque deposition and dendritic spine loss by applying two-photon in vivo microscopy through a cranial window in double transgenic APPPS1 mice. As a result, we first observed that the rate of dendritic spine loss in proximity to plaques is the same in both young and aged animals. However, plaque size only increased significantly in the young cohort, indicating that spine loss persists even many months after initial plaque appearance. Tracking the fate of individual spines revealed that net spine loss is caused by increased spine elimination, with the rate of spine formation remaining constant. Imaging of dendritic spines before and during plaque formation demonstrated that spine loss around plaques commences at least 4 weeks after initial plaque formation. In conclusion, spine loss occurs, shortly but with a significant time delay, after the birth of new plaques, and persists in the vicinity of amyloid plaques over many months. These findings hence give further hope to the possibility that there is a therapeutic window between initial amyloid plaque deposition and the onset of structural damage at spines.

  8. White Dwarf Convection Preceding Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Zingale, Michael; Almgren, A. S.; Bell, J. B.; Malone, C. M.; Nonaka, A.; Woosley, S. E.

    2010-01-01

    In the single degenerate scenario for Type Ia supernovae, a Chandrasekhar mass white dwarf `simmers' for centuries preceding the ultimate explosion. During this period, reactions near the center drive convection throughout most of the interior of the white dwarf. The details of this convective flow determine how the first flames in the white dwarf ignite. Simulating this phase is difficult because the flows are highly subsonic. Using the low Mach number hydrodynamics code, MAESTRO, we present 3-d, full star models of the final hours of this convective phase, up to the point of ignition of a Type Ia supernova. We discuss the details of the convective velocity field and the locations of the initial hot spots. Finally, we show some preliminary results with rotation. Support for this work came from the DOE/Office of Nuclear Physics, grant No. DE-FG02-06ER41448 (Stony Brook), the SciDAC Program of the DOE Office of Mathematics, Information, and Computational Sciences under the DOE under contract No. DE-AC02-05CH11231 (LBNL), and the DOE SciDAC program, under grant No. DE-FC02-06ER41438 (UCSC). We made use of the jaguar machine via a DOE INCITE allocation at the Oak Ridge Leadership Computational Facility.

  9. What precedes development of rheumatoid arthritis?

    PubMed Central

    Klareskog, L; Alfredsson, L; Rantapaa-Dahlqvis..., S; Berglin, E; Stolt, P; Padyukov, L

    2004-01-01

    Studies on aetiology of inflammatory diseases such as rheumatoid arthritis (RA) need to investigate the potential environmental triggers that are active before onset of disease, the genetic context in which these triggers act, and whether the presence of such triggers in an arthritis prone genetic context will give rise to the immune reactions associated with/preceding RA. Such knowledge would help not only to address much better the issue of causality of these potential triggers and the immune reactions, but also to carry out various interventions aimed at influencing the disease provoking immune events before development of clinical signs of disease. This short report summarises recent data demonstrating (a) the presence of anticitrullin antibodies or rheumatoid factors in between a third and half of patients with RA before development of clinical signs; (b) long term smoking is associated with a high risk of future development of seropositive but not seronegative RA; and (c) a strong gene–environment interaction between smoking and SE genes in the development of seropositive RA. We conclude that, in a certain genetic context, smoking is a potential trigger of RA, and a combination of the two factors is associated with the occurrence of immune reactions long before the onset of RA. PMID:15479868

  10. Segmentation precedes face categorization under suboptimal conditions

    PubMed Central

    Van Den Boomen, Carlijn; Fahrenfort, Johannes J.; Snijders, Tineke M.; Kemner, Chantal

    2015-01-01

    Both categorization and segmentation processes play a crucial role in face perception. However, the functional relation between these subprocesses is currently unclear. The present study investigates the temporal relation between segmentation-related and category-selective responses in the brain, using electroencephalography (EEG). Surface segmentation and category content were both manipulated using texture-defined objects, including faces. This allowed us to study brain activity related to segmentation and to categorization. In the main experiment, participants viewed texture-defined objects for a duration of 800 ms. EEG results revealed that segmentation-related responses precede category-selective responses. Three additional experiments revealed that the presence and timing of categorization depends on stimulus properties and presentation duration. Photographic objects were presented for a long and short (92 ms) duration and evoked fast category-selective responses in both cases. On the other hand, presentation of texture-defined objects for a short duration only evoked segmentation-related but no category-selective responses. Category-selective responses were much slower when evoked by texture-defined than by photographic objects. We suggest that in case of categorization of objects under suboptimal conditions, such as when low-level stimulus properties are not sufficient for fast object categorization, segmentation facilitates the slower categorization process. PMID:26074838

  11. Interaction of isopropylthioxanthone with phospholipid liposomes.

    PubMed

    Momo, Federico; Fabris, Sabrina; Stevanato, Roberto

    2007-04-01

    Isopropylthioxanthone (ITX) is a highly lipophilic molecule which can be released in foods and beverages from the packages, where it is present as photoinitiator of inks in printing processes. Recently it was found in babies milk, and its toxicity cannot be excluded. The structure of the molecule suggests a possible strong interaction with the lipid moiety of biological membranes, and this is the first study of its effects on phospholipid organization, using differential scanning calorimetry (DSC) and spin labelling techniques. The data obtained with multilamellar liposomes of saturated phospholipids of different length, with and without cholesterol, point out that the molecule changes the lipid structure; in particular, in the gel state, behaving like a disordering agent it increases the mobility of the bilayer, while, in the fluid state, tends to rigidify the membrane, in a cholesterol like way. This behavior supports the hypothesis that ITX experiences a relocation process when the lipid matrix passes from the gel to the fluid state.

  12. Phospholipid Bilayers: Stability and Encapsulation of Nanoparticles

    NASA Astrophysics Data System (ADS)

    Alipour, Elnaz; Halverson, Duncan; McWhirter, Samantha; Walker, Gilbert C.

    2017-05-01

    Nanoparticles are widely studied for their potential medical uses in diagnostics and therapeutics. The interface between a nanoparticle and its target has been a focus of research, both to guide the nanoparticle and to prevent it from deactivating. Given nature's frequent use of phospholipid vesicles as carriers, much attention has been paid to phospholipids as a vehicle for drug delivery. The physical chemistry of bilayer formation and nanoparticle encapsulation is complex, touching on fundamental properties of hydrophobicity. Understanding the design rules for particle synthesis and encapsulation is an active area of research. The aim of this review is to provide a perspective on what preparative guideposts have been empirically discovered and how these are related to theoretical understanding. In addition, we aim to summarize how modern theory is beginning to help guide the design of functional particles that can effectively cross biological membranes.

  13. Isolation and Characterization of a myo-inositol-1-phosphate Synthase Gene from Yellow Passion Fruit (Passiflora edulis f. flavicarpa) Expressed During Seed Development and Environmental Stress

    PubMed Central

    Abreu, Emanuel F. M.; Aragão, Francisco J. L.

    2007-01-01

    Background and Aims Myo-inositol-1l-phosphate synthase (MIPS) catalyses the conversion of d-glucose 6-phosphate to 1-l-myo-inositol-1-phosphate, the first and rate-limiting step in the biosynthesis of all inositol-containing compounds. Inositol phospholipids play a vital role in membrane trafficking and signalling pathways, auxin storage and transport, phytic acid biosynthesis, cell wall biosynthesis and production of stress-related molecules. In the present study, an MIPS cDNA from developing Passiflora edulis f. flavicarpa seeds was characterized and an investigation made into its spatial and differential expression, as well as changes in its transcription during exposure of growing plants to cold and heat stresses. Methods The MIPS-encoding gene was isolated by polymerase chain reaction (PCR) methods, and transcript levels were examined using semi-quantitative reverse transcription–PCR (RT–PCR) during seed development and in response to heat and cold stress. In addition, the copy number of the cloned PeMIPS1 gene in the genome of Passiflora edulis, P. eichleriana, P. caerulea, P. nitida and P. coccinea was determined by Southern blot analyses. Key Results A full-length cDNA clone of the PeMIPS1 from P. edulis was isolated and characterized. Southern blot analyses indicated that the genomic DNA might have diverse sequences of MIPS-encoding genes and one copy of the cloned PeMIPS1 gene in the genomes of P. edulis, P. eichleriana, P. caerulea, P. nitida and P. coccinea. RT–PCR expression analyses revealed the presence of PeMIPS1 transcripts in ovules, pollen grains and leaves, and during the seed developmental stages, where it peaked at 9 d after pollination. The PeMIPS1 gene is differentially regulated under cold and heat stress, presenting a light-responsive transcription. Conclusions Experimental data suggest that PeMIPS1 transcription plays an important role in the establishment of developmental programmes and during the response of plants to

  14. Isolation and characterization of a myo-inositol-1-phosphate synthase gene from yellow passion fruit (Passiflora edulis f. flavicarpa) expressed during seed development and environmental stress.

    PubMed

    Abreu, Emanuel F M; Aragão, Francisco J L

    2007-02-01

    Myo-inositol-1l-phosphate synthase (MIPS) catalyses the conversion of d-glucose 6-phosphate to 1-l-myo-inositol-1-phosphate, the first and rate-limiting step in the biosynthesis of all inositol-containing compounds. Inositol phospholipids play a vital role in membrane trafficking and signalling pathways, auxin storage and transport, phytic acid biosynthesis, cell wall biosynthesis and production of stress-related molecules. In the present study, an MIPS cDNA from developing Passiflora edulis f. flavicarpa seeds was characterized and an investigation made into its spatial and differential expression, as well as changes in its transcription during exposure of growing plants to cold and heat stresses. The MIPS-encoding gene was isolated by polymerase chain reaction (PCR) methods, and transcript levels were examined using semi-quantitative reverse transcription-PCR (RT-PCR) during seed development and in response to heat and cold stress. In addition, the copy number of the cloned PeMIPS1 gene in the genome of Passiflora edulis, P. eichleriana, P. caerulea, P. nitida and P. coccinea was determined by Southern blot analyses. A full-length cDNA clone of the PeMIPS1 from P. edulis was isolated and characterized. Southern blot analyses indicated that the genomic DNA might have diverse sequences of MIPS-encoding genes and one copy of the cloned PeMIPS1 gene in the genomes of P. edulis, P. eichleriana, P. caerulea, P. nitida and P. coccinea. RT-PCR expression analyses revealed the presence of PeMIPS1 transcripts in ovules, pollen grains and leaves, and during the seed developmental stages, where it peaked at 9 d after pollination. The PeMIPS1 gene is differentially regulated under cold and heat stress, presenting a light-responsive transcription. Experimental data suggest that PeMIPS1 transcription plays an important role in the establishment of developmental programmes and during the response of plants to environmental changes. The PeMIPS1 is differentially transcribed

  15. Metabolic effects of a novel silicate inositol complex of the nitric oxide precursor arginine in the obese insulin-resistant JCR:LA-cp rat.

    PubMed

    Proctor, Spencer D; Kelly, Sandra E; Vine, Donna F; Russell, James C

    2007-10-01

    Insulin resistance is a major contributor to macro- and microvascular complications, particularly in the presence of the metabolic syndrome, and is also associated with polycystic ovary syndrome. Impaired nitric oxide metabolism and endothelial function are important components of the vascular disease. Increasing the bioavailability of arginine, the precursor of nitric oxide, thus potentially offers protection against end-stage disease. We have recently demonstrated that dietary supplementation with a novel silicate inositol arginine complex reduces vasculopathy and glomerular sclerosis in the insulin-resistant JCR:LA-cp rat. The objective of this study was to address the absorption of, and the underlying metabolic alterations caused by, the arginine silicate inositol complex and arginine HCl (as a reference agent) in obese insulin-resistant male and female JCR:LA-cp rats. Male and female rats were treated with the preparations at 1.0 mg/(kg d) (expressed as arginine HCl) from 8 to 12 and 12 to 18 weeks of age, respectively. Obese female, but not male, rats treated with the arginine silicate inositol complex showed a reduced rate of weight gain without concomitant reduction in food intake. Plasma silicon levels were raised very significantly in arginine silicate-treated rats, consistent with significant absorption of the complex. In male rats, arginine levels were elevated by treatment with arginine silicate only; and female rats responded to both preparations. Plasma concentrations of oxides of nitrogen in rats treated with the silicate complex showed a dimorphism, decreasing in male and increasing in female rats. Fasting insulin levels were elevated in male rats treated with the arginine silicate complex, whereas fasting and postprandial insulin levels were decreased in female rats. Furthermore, female, but not male, rats treated with either of the arginine preparations showed significant reductions in cholesterol, triglyceride, and phospholipid concentrations

  16. Metabolomics uncovers a link between inositol metabolism and osteosarcoma metastasis

    PubMed Central

    Ren, Ling; Hong, Ellen S.; Mendoza, Arnulfo; Issaq, Sameer; Hoang, Christine Tran; Lizardo, Michael; LeBlanc, Amy; Khanna, Chand

    2017-01-01

    Cancer development and progression are characterized by complex molecular events. The acquisition of these events is primarily believed to result from alterations in gene and protein expression/function. Recent studies have also suggested the role of metabolic alterations, or “metabolic reprogramming,” that may similarly contribute to these events. Indeed, our previous investigations in osteosarcoma (OS) identified metabolic changes uniquely linked to metastasis. Based on those findings, here we sought to build a more detailed understanding of the specific alterations in metabolites or metabolic pathways that may be responsible for the observed metastasis-associated metabolic alterations, suggested by gene expression data. This was pursued using a combination of high-throughput liquid- and gas-chromatography-based mass spectrometry (LC/MS and GC/MS) for a global metabolic profiling/subtraction of four pairs of high/low metastatic OS cell lines. By comparing the identity and level of the metabolites between high/low metastatic cells, several metabolic pathways were identified to be differentially activated, such as arginine, glutathione, inositol and fatty acid metabolic pathways. To further interrogate these results, we investigated the effects of inositol pathway dysregulation, through the exposure of metastatic OS cells to IP6 (inositol hexaphosphate). Although IP6 exposures had modest to minimal effects on cell proliferation, we observed reduced cellular glycolysis, down-regulation of PI3K/Akt signaling and suppression of OS metastatic progression. Collectively these data supported further investigation of metabolic sensitivities as anti-metastatic strategies in a clinical setting as well as investigation of altered metabolomics associated with metastatic progression. PMID:28404949

  17. Colorimetric estimation of phospholipids in aqueous dispersions.

    PubMed

    Hallen, R M

    1980-05-01

    A method for the estimation of phospholipids in aqueous dispersions is described. The method is based on the formation of a lipid-molybdenum blue complex, which is extracted into chloroform from the aqueous phase. Phosphate ions, detergents, proteins, neutral lipids and various other ions do not interfere in the lipid estimation. The method is sensitive down to a lipid concentration of 0.1 mumol/ml, with an accuracy better than +/- 3%.

  18. Visualization of Ca2+-Induced Phospholipid Domains

    NASA Astrophysics Data System (ADS)

    Haverstick, Doris M.; Glaser, Michael

    1987-07-01

    Large vesicles (5-15 μ m) were formed by hydrating a dried lipid film containing phospholipids labeled with a fluorophore in one fatty acid chain. By using a fluorescence microscope attached to a low-light-intensity charge-coupled-device camera and digital-image processor, the vesicles were easily viewed and initially showed uniform fluorescence intensity across the surface. The fluorescence pattern of vesicles made with a fluorophore attached to phosphatidylcholine or phosphatidylethanolamine was unaffected by the presence of divalent cations such as Ca2+, Mg2+, Mn2+, Zn2+, or Cd2+. The fluorescence pattern of vesicles containing a fluorophore attached to the acidic phospholipids phosphatidylserine or phosphatidic acid showed distinct differences when treated with Ca2+ or Cd2+, although they were unaffected by Mg2+, Mn2+, or Zn2+. Treatment with 2.0 mM Ca2+ or Cd2+ resulted in the movement of the fluorophore to a single large patch on the surface of the vesicle. When vesicles were formed in the presence of 33 mol% cholesterol, patching was seen at a slightly lower Ca2+ concentration (1.0 mM). The possibility of interactions between Ca2+ and acidic phospholipids in plasma membranes was investigated by labeling erythrocytes and erythrocyte ghosts with fluorescent phosphatidic acid. When Ca2+ was added, multiple (five or six) small patches were seen per individual cell. The same pattern was observed when vesicles formed from whole lipid extracts of erythrocytes were labeled with fluorescent phosphatidic acid and then treated with Ca2+. This shows that the size and distribution of the Ca2+-induced domains depend on phospholipid composition.

  19. Defective Craniofacial Development and Brain Function in a Mouse Model for Depletion of Intracellular Inositol Synthesis*

    PubMed Central

    Ohnishi, Tetsuo; Murata, Takuya; Watanabe, Akiko; Hida, Akiko; Ohba, Hisako; Iwayama, Yoshimi; Mishima, Kazuo; Gondo, Yoichi; Yoshikawa, Takeo

    2014-01-01

    myo-Inositol is an essential biomolecule that is synthesized by myo-inositol monophosphatase (IMPase) from inositol monophosphate species. The enzymatic activity of IMPase is inhibited by lithium, a drug used for the treatment of mood swings seen in bipolar disorder. Therefore, myo-inositol is thought to have an important role in the mechanism of bipolar disorder, although the details remain elusive. We screened an ethyl nitrosourea mutant mouse library for IMPase gene (Impa) mutations and identified an Impa1 T95K missense mutation. The mutant protein possessed undetectable enzymatic activity. Homozygotes died perinatally, and E18.5 embryos exhibited striking developmental defects, including hypoplasia of the mandible and asymmetric fusion of ribs to the sternum. Perinatal lethality and morphological defects in homozygotes were rescued by dietary myo-inositol. Rescued homozygotes raised on normal drinking water after weaning exhibited a hyper-locomotive trait and prolonged circadian periods, as reported in rodents treated with lithium. Our mice should be advantageous, compared with those generated by the conventional gene knock-out strategy, because they carry minimal genomic damage, e.g. a point mutation. In conclusion, our results reveal critical roles for intracellular myo-inositol synthesis in craniofacial development and the maintenance of proper brain function. Furthermore, this mouse model for cellular inositol depletion could be beneficial for understanding the molecular mechanisms underlying the clinical effect of lithium and myo-inositol-mediated skeletal development. PMID:24554717

  20. Retinoic acid treatment of fibroblasts causes a rapid decrease in ( sup 3 H)inositol uptake

    SciTech Connect

    Sinha, R.; Creek, K.E.; Silverman-Jones, C.; de Luca, L.M. )

    1989-04-01

    NIH 3T3 fibroblasts treated with all-trans-retinoic acid (RA) showed a dramatic decrease in the uptake of ({sup 3}H)inositol compared to solvent-treated controls. The onset of RA-induced inhibition of ({sup 3}H)inositol uptake was rapid with a 10-15% decrease occurring after 2-3 h of RA exposure and 60-70% reduction after 16 h of RA treatment. A progressive dose-dependent decrease in inositol uptake was found as the concentration of RA increased from 10{sup {minus}8} to 10{sup {minus}5} M and the effect was fully reversible within 48 h after RA removal. RA inhibition of inositol uptake was also observed in 3T3-Swiss and Balb/3T3 cells but not in two virally transformed 3T3 cell lines. Phlorizin, amiloride, and monensin inhibited inositol uptake by 66, 74, and 58%, respectively, and this inhibition was additive when the cells were treated with RA as well as these inhibitors. A decreased incorporation of ({sup 3}H)inositol into polyphosphoinositides was also observed in RA-treated cells but not to the same extent as for ({sup 3}H)inositol uptake. In conclusion, RA treatment of 3T3 fibroblasts decreases the uptake of ({sup 3}H)inositol by up to 70% within 8 to 10 h at near physiological concentrations in a reversible and specific manner.

  1. The nutritional significance, metabolism, and function of myo-inositol and phosphatidylinositol in health and disease.

    PubMed

    Holub, B J

    1982-01-01

    Recent advances in nutritional and biochemical research have substantiated the importance of inositol as a dietary and cellular constituent. The processes involved in the metabolism of inositol and its derivatives in mammalian tissues have been characterized both in vivo and at the enzyme level. Biochemical functions elucidated for phosphatidylinositol in biological membranes include the mediation of cellular responses to external stimuli, nerve transmission, and the regulation of enzyme activity through specific interactions with various proteins. Inositol deficiency in animals has been shown to produce an accumulation of triglyceride in liver, intestinal lipodystrophy, and other abnormalities. The metabolic mechanisms giving rise to these latter phenomena have been extensively studied as a function of dietary inositol. Altered metabolism of inositol has been documented in patients with diabetes mellitus, chronic renal failure, galactosemia, and multiple sclerosis. A moderate increase in plasma and nerve inositol levels by dietary supplementation has been suggested as a means of treating diabetic neuropathy, although excessively high levels, such as are found in uremic patients, may be neurotoxic. A thorough consideration of the biochemical functions of inositol and a further characterization of various diseases with the aid of appropriate animal models may suggest a possible role for inositol and other dietary components in their prevention and treatment

  2. GIPC: Glycosyl Inositol Phospho Ceramides, the major sphingolipids on earth.

    PubMed

    Gronnier, Julien; Germain, Véronique; Gouguet, Paul; Cacas, Jean-Luc; Mongrand, Sébastien

    2016-01-01

    What are the most abundant sphingolipids on earth? The answer is Glycosyl Inositol Phosphoryl Ceramides (GIPCs) present in fungi and the green lineage. In this review, we discuss the putative role of plant GIPCs in the lipid bilayer asymmetry, in the lateral organization of membrane rafts and in the very long chain fatty acid inter-leaflet coupling of lipids in the plant plasma membrane (PM). A special focus on the structural similarities -and putative functions- of GIPCs is discussed by comparison with animal gangliosides, structural homologs of plant GIPCs.

  3. GIPC: Glycosyl Inositol Phospho Ceramides, the major sphingolipids on earth

    PubMed Central

    Gronnier, Julien; Germain, Véronique; Gouguet, Paul; Cacas, Jean-Luc; Mongrand, Sébastien

    2016-01-01

    ABSTRACT What are the most abundant sphingolipids on earth? The answer is Glycosyl Inositol Phosphoryl Ceramides (GIPCs) present in fungi and the green lineage. In this review, we discuss the putative role of plant GIPCs in the lipid bilayer asymmetry, in the lateral organization of membrane rafts and in the very long chain fatty acid inter-leaflet coupling of lipids in the plant plasma membrane (PM). A special focus on the structural similarities -and putative functions- of GIPCs is discussed by comparison with animal gangliosides, structural homologs of plant GIPCs. PMID:27074617

  4. Protein pyrophosphorylation by inositol pyrophosphates is a posttranslational event

    PubMed Central

    Bhandari, Rashna; Saiardi, Adolfo; Ahmadibeni, Yousef; Snowman, Adele M.; Resnick, Adam C.; Kristiansen, Troels Z.; Molina, Henrik; Pandey, Akhilesh; Werner, J. Kent; Juluri, Krishna R.; Xu, Yong; Prestwich, Glenn D.; Parang, Keykavous; Snyder, Solomon H.

    2007-01-01

    In a previous study, we showed that the inositol pyrophosphate diphosphoinositol pentakisphosphate (IP7) physiologically phosphorylates mammalian and yeast proteins. We now report that this phosphate transfer reflects pyrophosphorylation. Thus, proteins must be prephosphorylated by ATP to prime them for IP7 phosphorylation. IP7 phosphorylates synthetic phosphopeptides but not if their phosphates have been masked by methylation or pyrophosphorylation. Moreover, IP7 phosphorylated peptides are more acid-labile and more resistant to phosphatases than ATP phosphorylated peptides, indicating a different type of phosphate bond. Pyrophosphorylation may represent a novel mode of signaling to proteins. PMID:17873058

  5. Characterization of Inositol-containing Phosphosphingolipids from Tobacco Leaves

    PubMed Central

    Kaul, Karan; Lester, Robert L.

    1975-01-01

    A method for a large scale extraction of phosphoglycosphingolipids from the leaves of Nicotiana tabacum L. has been developed. The phosphosphingolipid concentrate consists of a dozen or more polar lipids as judged by thin layer chromatography. Two of these lipids were purified by chromatography on porous silica beads and partially characterized. These lipids are formulated as: N-acetylglucosamidoglucuronidoinositol phosphorylceramide and glucosamidoglucuronidoinositol phosphorylceramide. Although not fully characterized, the other lipids in the concentrate are inositol-containing phosphosphingolipids with a higher carbohydrate content. PMID:16659016

  6. Phylogenomic investigation of phospholipid synthesis in archaea.

    PubMed

    Lombard, Jonathan; López-García, Purificación; Moreira, David

    2012-01-01

    Archaea have idiosyncratic cell membranes usually based on phospholipids containing glycerol-1-phosphate linked by ether bonds to isoprenoid lateral chains. Since these phospholipids strongly differ from those of bacteria and eukaryotes, the origin of the archaeal membranes (and by extension, of all cellular membranes) was enigmatic and called for accurate evolutionary studies. In this paper we review some recent phylogenomic studies that have revealed a modified mevalonate pathway for the synthesis of isoprenoid precursors in archaea and suggested that this domain uses an atypical pathway of synthesis of fatty acids devoid of any acyl carrier protein, which is essential for this activity in bacteria and eukaryotes. In addition, we show new or updated phylogenetic analyses of enzymes likely responsible for the isoprenoid chain synthesis from their precursors and the phospholipid synthesis from glycerol phosphate, isoprenoids, and polar head groups. These results support that most of these enzymes can be traced back to the last archaeal common ancestor and, in many cases, even to the last common ancestor of all living organisms.

  7. Phospholipid nanodisc engineering for drug delivery systems.

    PubMed

    Murakami, Tatsuya

    2012-06-01

    Biocompatible mesoscale nanoparticles (5-100 nm in diameter) are attractive tools for drug delivery. Among them are several types of liposomes and polymer micelles already in clinical trial or use. Generally, biocompatibility of such particles is achieved by coating them with polyethylene glycol (PEG). Without PEG coating, particles are quickly trapped in the reticuloendothelial system when intravenously administered. However, recent studies have revealed several potential problems with PEG coating, including antigenicity and restriction of cellular uptake. This has motivated the development of alternative drug and gene delivery vehicles, including chemically and genetically engineered high-density lipoprotein (HDL)-like nanodiscs or "bicelles". HDL is a naturally occurring mesoscale nanoparticle that normally ferries cholesterol around in the body. Its initial "nascent" form is thought to be a simple 10 nm disc of phospholipids in a bilayer, and can be easily synthesized in vitro by mixing recombinant apoA-I proteins with various phospholipids. In this review, the use of synthetic HDL-like phospholipid nanodiscs as biocompatible drug carriers is summarized, focussing on manufacturing, size-control, drug loading and cell targeting. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Cholesterol autoxidation in phospholipid membrane bilayers

    SciTech Connect

    Sevanian, A.; McLeod, L.L.

    1987-09-01

    Lipid peroxidation in unilamellar liposomes of known cholesterol-phospholipid composition was monitored under conditions of autoxidation or as induced by a superoxide radical generating system, gamma-irradiation or cumene hydroperoxide. Formation of cholesterol oxidation products was indexed to the level of lipid peroxidation. The major cholesterol oxidation products identified were 7-keto-cholesterol, isomeric cholesterol 5,6-epoxides, isomeric 7-hydroperoxides and isomeric 3,7-cholestane diols. Other commonly encountered products included 3,5-cholestadiene-7-one and cholestane-3 beta, 5 alpha, 6 beta-triol. Superoxide-dependent peroxidation required iron and produced a gradual increase in 7-keto-cholesterol and cholesterol epoxides. Cholesterol oxidation was greatest in liposomes containing high proportions of unsaturated phospholipid to cholesterol (4:1 molar ratio), intermediate with low phospholipid to cholesterol ratios (2:1) and least in liposomes prepared with dipalmitoylphosphatidylcholine and cholesterol. This relationship held regardless of the oxidizing conditions used. Cumene hydroperoxide-dependent lipid peroxidation and/or more prolonged oxidations with other oxidizing systems yielded a variety of products where cholesterol-5 beta,6 beta-epoxide, 7-ketocholesterol and the 7-hydroperoxides were most consistently elevated. Oxyradical initiation of lipid peroxidation produced a pattern of cholesterol oxidation products distinguishable from the pattern derived by cumene hydroperoxide-dependent peroxidation.

  9. Abnormalities in myo-inositol metabolism associated with type 2 diabetes in mice fed a high-fat diet: benefits of a dietary myo-inositol supplementation.

    PubMed

    Croze, Marine L; Géloën, Alain; Soulage, Christophe O

    2015-06-28

    We previously reported that a chronic supplementation with myo-inositol (MI) improved insulin sensitivity and reduced fat accretion in mice. We then tested the potency of such dietary intervention in the prevention of insulin resistance in C57BL/6 male mouse fed a high-fat diet (HFD). In addition, some abnormalities in inositol metabolism were reported to be associated with insulin resistance in several animal and human studies. We then investigated the presence of such anomalies (i.e. inosituria and an inositol intra-tissue depletion) in this diet-induced obesity (DIO) mouse model, as well as the potential benefit of a MI supplementation for inositol intra-tissue deficiency correction. HFD (60 % energy from fat) feeding was associated with inosituria and inositol intra-tissue depletion in the liver and kidneys. MI supplementation (0·58 mg/g per d) restored inositol pools in kidneys (partially) and liver (fully). HFD feeding for 4 months induced ectopic lipid redistribution to liver and muscles, fasting hyperglycaemia and hyperinsulinaemia, insulin resistance and obesity that were not prevented by MI supplementation, despite a significant improvement in insulin sensitivity parameter K insulin tolerance test and a reduction in white adipose tissue (WAT) mass ( - 17 %, P< 0·05). MI supplementation significantly reduced fatty acid synthase activity in epididymal WAT, which might explain its beneficial, but modest, effect on WAT accretion in HFD-fed mice. Finally, we found some abnormalities in inositol metabolism in association with a diabetic phenotype (i.e. insulin resistance and fasting hyperglycaemia) in a DIO mouse model. Dietary MI supplementation was efficient in the prevention of inositol intra-tissue depletion, but did not prevent insulin resistance or obesity efficiently in this mouse model.

  10. Degradation of myo-inositol hexakisphosphate by a phytate-degrading enzyme from Pantoea agglomerans.

    PubMed

    Greiner, Ralf

    2004-11-01

    High-pressure liquid chromatography (HPLC) analysis established myo-inositol pentakisphosphate as the final product of phytate dephosphorylation by the phytate-degrading enzyme from Pantoea agglomerans. Neither product inhibition by phosphate nor inactivation of the Pantoea enzyme during the incubation period were responsible for the limited phytate hydrolysis as shown by addition of phytate-degrading enzyme and phytate, respectively, after the observed stop of enzymatic phytate degradation. In additon, the Pantoea enzyme did not possess activity toward the purified myo-inositol pentakisphosphate. Using a combination of High-Performance Ion Chromatography (HPIC) analysis and kinetic studies, the nature of the generated myo-inositol pentakisphosphate was established. The data demonstrate that the phytate-degrading enzyme from Pantoea agglomerans dephosphorylates myo-inositol hexakisphosphate in a stereospecific way to finally D-myo-inositol(1,2,4,5,6)pentakisphosphate.

  11. Levoprotiline ((-)-oxaprotiline) effects on inositol phosphate generation in human peripheral lymphocytes.

    PubMed

    Schubert, T; Müller, W E

    1991-01-01

    The effects of the atypical antidepressant levoprotiline (LPT) on inositol phosphate metabolism were investigated in N-formyl-methionyl-leucylphenylalanine (fMLP) activated human lymphocytes. In the presence of LPT, stimulation of phosphoinositide hydrolysis by fMLP lead to an increased accumulation of inositol bisphosphates, an effect which could be detected within the range of therapuetic plasma concentrations and which is exerted by lithium in a similar way. Furthermore, incubation of lymphocytes with LPT and subsequent stimulation with fMLP lead to a pronounced decrease in the level of free intracellular [3H]inositol. Both LPT effects, the increased accumulation of inositol bisphosphates and the reduction of free intracellular [3H]inositol, were found to be more pronounced for LPT than for its enantiomer (+)-oxaprotiline. The results are discussed in view of a possible biochemical mechanism which may contribute to the antidepressive activity of LPT.

  12. Specificity determinants in phosphoinositide dephosphorylation: crystal structure of an archetypal inositol polyphosphate 5-phosphatase.

    PubMed

    Tsujishita, Y; Guo, S; Stolz, L E; York, J D; Hurley, J H

    2001-05-04

    Inositol polyphosphate 5-phosphatases are central to intracellular processes ranging from membrane trafficking to Ca(2+) signaling, and defects in this activity result in the human disease Lowe syndrome. The 1.8 resolution structure of the inositol polyphosphate 5-phosphatase domain of SPsynaptojanin bound to Ca(2+) and inositol (1,4)-bisphosphate reveals a fold and an active site His and Asp pair resembling those of several Mg(2+)-dependent nucleases. Additional loops mediate specific inositol polyphosphate contacts. The 4-phosphate of inositol (1,4)-bisphosphate is misoriented by 4.6 compared to the reactive geometry observed in the apurinic/apyrimidinic endonuclease 1, explaining the dephosphorylation site selectivity of the 5-phosphatases. Based on the structure, a series of mutants are described that exhibit altered substrate specificity providing general determinants for substrate recognition.

  13. Ion chromatographic determination of inositol in infant formulae and clinical products for enteral feeding.

    PubMed

    Tagliaferri, E G; Bonetti, G; Blake, C J

    2000-05-26

    An ion chromatographic method is described for the determination of inositol in infant formula and products for enteral feeding. A two-step procedure for hydrolysis and extraction of total inositol has been developed, involving alkaline hydrolysis with 3 M potassium hydroxide and enzymatic dephosphorylation. Substances having a long chromatographic retention time were removed with an ion-exchange resin. Inositol was separated on a high-resolution ion-exchange column and detected by pulsed amperometric detection. Phytic acid interferes only slightly in the analysis. This method can be used for determination of total inositol in infant formulae, and enteral feeding products. The analytical method gave an average recovery of 94% from infant formula samples spiked with inositol and a recovery of 86+/-3% from products spiked with lecithin.

  14. Insights into the activation mechanism of class I HDAC complexes by inositol phosphates

    PubMed Central

    Watson, Peter J.; Millard, Christopher J.; Riley, Andrew M.; Robertson, Naomi S.; Wright, Lyndsey C.; Godage, Himali Y.; Cowley, Shaun M.; Jamieson, Andrew G.; Potter, Barry V. L.; Schwabe, John W. R.

    2016-01-01

    Histone deacetylases (HDACs) 1, 2 and 3 form the catalytic subunit of several large transcriptional repression complexes. Unexpectedly, the enzymatic activity of HDACs in these complexes has been shown to be regulated by inositol phosphates, which bind in a pocket sandwiched between the HDAC and co-repressor proteins. However, the actual mechanism of activation remains poorly understood. Here we have elucidated the stereochemical requirements for binding and activation by inositol phosphates, demonstrating that activation requires three adjacent phosphate groups and that other positions on the inositol ring can tolerate bulky substituents. We also demonstrate that there is allosteric communication between the inositol-binding site and the active site. The crystal structure of the HDAC1:MTA1 complex bound to a novel peptide-based inhibitor and to inositol hexaphosphate suggests a molecular basis of substrate recognition, and an entropically driven allosteric mechanism of activation. PMID:27109927

  15. Cholinesterase inhibitor soman increases inositol trisphosphate in rat brain. (Reannouncement with new availability information)

    SciTech Connect

    Mobley, P.L.

    1990-12-31

    Studies were conducted to determine the effect of the cholinesterase inhibitor soman on the amount of inositol trisphosphate in the neocortex, striatum, cerebellum, and medulla-pons regions of rat brain in vivo. The studies indicate that treatment with soman increase inositol trisphosphate in the neocortex and striatum, but not in the cerebellum or medulla-pons region. In the neocortex the most pronounced increases were observed in animals with severe poisoning symptoms; however, inositol trisphophate was also found to be elevated in animals with only mild poisoning symptoms. A variety of evidence suggests that the receptor-mediated hydrolysis of phosphatidyl inositol results in the formation of inositol trisphosphate (IP3) and diacylglycerol, both of which function as intracellular signal messengers, and that this mechanism represents a major signal transduction system through which extracellular signals can influence intracellular events.

  16. PAH1-encoded phosphatidate phosphatase plays a role in the growth phase- and inositol-mediated regulation of lipid synthesis in Saccharomyces cerevisiae.

    PubMed

    Pascual, Florencia; Soto-Cardalda, Aníbal; Carman, George M

    2013-12-13

    In the yeast Saccharomyces cerevisiae, the synthesis of phospholipids in the exponential phase of growth occurs at the expense of the storage lipid triacylglycerol. As exponential phase cells progress into the stationary phase, the synthesis of triacylglycerol occurs at the expense of phospholipids. Early work indicates a role of the phosphatidate phosphatase (PAP) in this metabolism; the enzyme produces the diacylglycerol needed for the synthesis of triacylglycerol and simultaneously controls the level of phosphatidate for the synthesis of phospholipids. Four genes (APP1, DPP1, LPP1, and PAH1) encode PAP activity in yeast, and it has been unclear which gene is responsible for the synthesis of triacylglycerol throughout growth. An analysis of lipid synthesis and composition, as well as PAP activity in various PAP mutant strains, showed the essential role of PAH1 in triacylglycerol synthesis throughout growth. Pah1p is a phosphorylated enzyme whose in vivo function is dependent on its dephosphorylation by the Nem1p-Spo7p protein phosphatase complex. nem1Δ mutant cells exhibited defects in triacylglycerol synthesis and lipid metabolism that mirrored those imparted by the pah1Δ mutation, substantiating the importance of Pah1p dephosphorylation throughout growth. An analysis of cells bearing PPAH1-lacZ and PPAH1-DPP1 reporter genes showed that PAH1 expression was induced throughout growth and that the induction in the stationary phase was stimulated by inositol supplementation. A mutant analysis indicated that the Ino2p/Ino4p/Opi1p regulatory circuit and transcription factors Gis1p and Rph1p mediated this regulation.

  17. PAH1-encoded Phosphatidate Phosphatase Plays a Role in the Growth Phase- and Inositol-mediated Regulation of Lipid Synthesis in Saccharomyces cerevisiae*

    PubMed Central

    Pascual, Florencia; Soto-Cardalda, Aníbal; Carman, George M.

    2013-01-01

    In the yeast Saccharomyces cerevisiae, the synthesis of phospholipids in the exponential phase of growth occurs at the expense of the storage lipid triacylglycerol. As exponential phase cells progress into the stationary phase, the synthesis of triacylglycerol occurs at the expense of phospholipids. Early work indicates a role of the phosphatidate phosphatase (PAP) in this metabolism; the enzyme produces the diacylglycerol needed for the synthesis of triacylglycerol and simultaneously controls the level of phosphatidate for the synthesis of phospholipids. Four genes (APP1, DPP1, LPP1, and PAH1) encode PAP activity in yeast, and it has been unclear which gene is responsible for the synthesis of triacylglycerol throughout growth. An analysis of lipid synthesis and composition, as well as PAP activity in various PAP mutant strains, showed the essential role of PAH1 in triacylglycerol synthesis throughout growth. Pah1p is a phosphorylated enzyme whose in vivo function is dependent on its dephosphorylation by the Nem1p-Spo7p protein phosphatase complex. nem1Δ mutant cells exhibited defects in triacylglycerol synthesis and lipid metabolism that mirrored those imparted by the pah1Δ mutation, substantiating the importance of Pah1p dephosphorylation throughout growth. An analysis of cells bearing PPAH1-lacZ and PPAH1-DPP1 reporter genes showed that PAH1 expression was induced throughout growth and that the induction in the stationary phase was stimulated by inositol supplementation. A mutant analysis indicated that the Ino2p/Ino4p/Opi1p regulatory circuit and transcription factors Gis1p and Rph1p mediated this regulation. PMID:24196957

  18. Stereospecificity of myo-inositol hexakisphosphate hydrolysis by a protein tyrosine phosphatase-like inositol polyphosphatase from Megasphaera elsdenii.

    PubMed

    Puhl, Aaron A; Greiner, Ralf; Selinger, L Brent

    2009-02-01

    Inositol polyphosphatases (IPPases), particularly those that can hydrolyze myo-inositol hexakisphosphate (Ins P(6)), are of biotechnological interest for their ability to reduce the metabolically unavailable organic phosphate content of feedstuffs and to produce lower inositol polyphosphates (IPPs) for research and pharmaceutical applications. Here, the gene coding for a new protein tyrosine phosphatase (PTP)-like IPPase was cloned from Megasphaera elsdenii (phyAme), and the biochemical properties of the recombinant protein were determined. The deduced amino acid sequence of PhyAme is similar to known PTP-like IPPases (29-44% identity), and the recombinant enzyme displayed strict specificity for IPP substrates. Optimal IPPase activity was displayed at an ionic strength of 250 mM, a pH of 5.0, and a temperature of 60 degrees C. In order to elucidate its stereospecificity of Ins P(6) dephosphorylation, a combination of high-performance ion-pair chromatography and kinetic studies was conducted. PhyAme displayed a stereospecificity that is unique among enzymes belonging to this class in that it preferentially cleaved Ins P(6) at one of two phosphate positions, 1D-3 or 1D-4. PhyAme followed two distinct and specific routes of hydrolysis, predominantly degrading Ins P(6) to Ins(2)P via: (a) 1D-Ins(1,2,4,5,6)P(5), 1D-Ins(1,2,5,6)P(4), 1D-Ins(1,2,6)P(3), and 1D-Ins(1,2)P(2) (60%) and (b) 1D-Ins(1,2,3,5,6)P(5), 1D-Ins(1,2,3,6)P(4), Ins(1,2,3)P(3), and D/L-Ins(1,2)P(2)(35%).

  19. Results from the International Consensus Conference on myo-inositol and D-chiro-inositol in Obstetrics and Gynecology--assisted reproduction technology.

    PubMed

    Bevilacqua, Arturo; Carlomagno, Gianfranco; Gerli, Sandro; Montanino Oliva, Mario; Devroey, Paul; Lanzone, Antonio; Soulange, Christophe; Facchinetti, Fabio; Carlo Di Renzo, Gian; Bizzarri, Mariano; Hod, Moshe; Cavalli, Pietro; D'Anna, Rosario; Benvenga, Salvatore; Chiu, Tony T; Kamenov, Zdravko A

    2015-06-01

    A substantial body of research on mammalian gametogenesis and human reproduction has recently investigated the effect of myo-inositol (MyoIns) on oocyte and sperm cell quality, due to its possible application to medically assisted reproduction. With a growing number of both clinical and basic research papers, the meaning of several observations now needs to be interpreted under a solid and rigorous physiological framework. The 2013 Florence International Consensus Conference on Myo- and D-chiro-inositol in obstetrics and gynecology has answered a number of research questions concerning the use of the two stereoisomers in assisted reproductive technologies. Available clinical trials and studies on the physiological and pharmacological effects of these molecules have been surveyed. Specifically, the physiological involvement of MyoIns in oocyte maturation and sperm cell functions has been discussed, providing an answer to the following questions: (1) Are inositols physiologically involved in oocyte maturation? (2) Are inositols involved in the physiology of spermatozoa function? (3) Is treatment with inositols helpful within assisted reproduction technology cycles? (4) Are there any differences in clinical efficacy between MyoIns and D-chiro-inositol? The conclusions of this Conference, drawn depending on expert panel opinions and shared with all the participants, are summarized in this review paper.

  20. Antidiabetic phospholipid-nuclear receptor complex reveals the mechanism for phospholipid-driven gene regulation

    SciTech Connect

    Musille, Paul M; Pathak, Manish C; Lauer, Janelle L; Hudson, William H; Griffin, Patrick R; Ortlund, Eric A

    2013-01-31

    The human nuclear receptor liver receptor homolog-1 (LRH-1) has an important role in controlling lipid and cholesterol homeostasis and is a potential target for the treatment of diabetes and hepatic diseases. LRH-1 is known to bind phospholipids, but the role of phospholipids in controlling LRH-1 activation remains highly debated. Here we describe the structure of both apo LRH-1 and LRH-1 in complex with the antidiabetic phospholipid dilauroylphosphatidylcholine (DLPC). Together with hydrogen-deuterium exchange MS and functional data, our studies show that DLPC binding is a dynamic process that alters co-regulator selectivity. We show that the lipid-free receptor undergoes previously unrecognized structural fluctuations, allowing it to interact with widely expressed co-repressors. These observations enhance our understanding of LRH-1 regulation and highlight its importance as a new therapeutic target for controlling diabetes.

  1. myo-Inositol and d-Ribose Ligand Discrimination in an ABC Periplasmic Binding Protein

    PubMed Central

    Herrou, Julien

    2013-01-01

    The periplasmic binding protein (PBP) IbpA mediates the uptake of myo-inositol by the IatP-IatA ATP-binding cassette transmembrane transporter. We report a crystal structure of Caulobacter crescentus IbpA bound to myo-inositol at 1.45 Å resolution. This constitutes the first structure of a PBP bound to inositol. IbpA adopts a type I PBP fold consisting of two α-β lobes that surround a central hinge. A pocket positioned between the lobes contains the myo-inositol ligand, which binds with submicromolar affinity (0.76 ± 0.08 μM). IbpA is homologous to ribose-binding proteins and binds d-ribose with low affinity (50.8 ± 3.4 μM). On the basis of IbpA and ribose-binding protein structures, we have designed variants of IbpA with inverted binding specificity for myo-inositol and d-ribose. Five mutations in the ligand-binding pocket are sufficient to increase the affinity of IbpA for d-ribose by 10-fold while completely abolishing binding to myo-inositol. Replacement of ibpA with these mutant alleles unable to bind myo-inositol abolishes C. crescentus growth in medium containing myo-inositol as the sole carbon source. Neither deletion of ibpA nor replacement of ibpA with the high-affinity ribose binding allele affected C. crescentus growth on d-ribose as a carbon source, providing evidence that the IatP-IatA transporter is specific for myo-inositol. This study outlines the evolutionary relationship between ribose- and inositol-binding proteins and provides insight into the molecular basis upon which these two related, but functionally distinct, classes of periplasmic proteins specifically bind carbohydrate ligands. PMID:23504019

  2. Inositol trisphosphate stimulates calcium release from peeled skeletal muscle fibers.

    PubMed

    Donaldson, S K; Goldberg, N D; Walseth, T F; Huetteman, D A

    1987-01-19

    The effects of inositol phosphates (tris (InsP3), bis (InsP2), mono (InsP)) on rabbit adductor magnus and soleus muscles were determined using mechanically peeled fibers (sarcolemma removed). Isometric force generation of each fiber was continuously monitored and was used along with 45Ca to detect calcium release from internal fiber stores. All experiments were conducted at a physiological Mg2+ concentration (10(-3) M) of the bathing solutions. The inositol phosphates did not directly activate the contractile apparatus. At bath concentrations of 100-300 microM, only InsP3 was capable of stimulating Ca2+ release. In contrast, 1 microM InsP3 maximally and selectively stimulated Ca2+ release when microinjected into the myofilament lattice. Calcium releasing effects of InsP2 and InsP were manifested at 10 microM when they were microinjected. The end-to-end internal Ca2+ release and subsequent fiber force generation stimulated by the locally applied microinjected InsP3 suggests that the InsP3-induced Ca2+ release mechanism may involve propagation, but not via the Ca2+-induced Ca2+ release, since procaine did not inhibit this response. These findings support the possibility that InsP3 plays a role in skeletal muscle excitation-contraction coupling.

  3. Inositol Hexakisphosphate Kinase 3 Regulates Metabolism and Lifespan in Mice

    PubMed Central

    Moritoh, Yusuke; Oka, Masahiro; Yasuhara, Yoshitaka; Hozumi, Hiroyuki; Iwachidow, Kimihiko; Fuse, Hiromitsu; Tozawa, Ryuichi

    2016-01-01

    Inositol hexakisphosphate kinase 3 (IP6K3) generates inositol pyrophosphates, which regulate diverse cellular functions. However, little is known about its own physiological role. Here, we show the roles of IP6K3 in metabolic regulation. We detected high levels of both mouse and human IP6K3 mRNA in myotubes and muscle tissues. In human myotubes, IP6K3 was upregulated by dexamethasone treatment, which is known to inhibit glucose metabolism. Furthermore, Ip6k3 expression was elevated under diabetic, fasting, and disuse conditions in mouse skeletal muscles. Ip6k3−/− mice demonstrated lower blood glucose, reduced circulating insulin, deceased fat mass, lower body weight, increased plasma lactate, enhanced glucose tolerance, lower glucose during an insulin tolerance test, and reduced muscle Pdk4 expression under normal diet conditions. Notably, Ip6k3 deletion extended animal lifespan with concomitant reduced phosphorylation of S6 ribosomal protein in the heart. In contrast, Ip6k3−/− mice showed unchanged skeletal muscle mass and no resistance to the effects of high fat diet. The current observations suggest novel roles of IP6K3 in cellular regulation, which impact metabolic control and lifespan. PMID:27577108

  4. Effect of acute thioacetamide administration on rat brain phospholipid metabolism

    SciTech Connect

    Osada, J.; Aylagas, H.; Miro-Obradors, M.J.; Arce, C.; Palacios-Alaiz, E.; Cascales, M. )

    1990-09-01

    Brain phospholipid composition and the ({sup 32}P)orthophosphate incorporation into brain phospholipids of control and rats treated for 3 days with thioacetamide were studied. Brain phospholipid content, phosphatidylcholine, phosphatidylethanolamine, lysolecithin and phosphatidic acid did not show any significant change by the effect of thioacetamide. In contrast, thioacetamide induced a significant decrease in the levels of phosphatidylserine, sphingomyelin, phosphatidylinositol and diphosphatidylglycerol. After 75 minutes of intraperitoneal label injection, specific radioactivity of all the above phospholipids with the exception of phosphatidylethanolamine and phosphatidylcholine significantly increased. After 13 hours of isotope administration the specific radioactivity of almost all studied phospholipid classes was elevated, except for phosphatidic acid, the specific radioactivity of which did not change and for diphosphatidylglycerol which showed a decrease in specific radioactivity. These results suggest that under thioacetamide treatment brain phospholipids undergo metabolic transformations that may contribute to the hepatic encephalopathy induced by thioacetamide.

  5. The Lantibiotic Nisin Induces Transmembrane Movement of a Fluorescent Phospholipid

    PubMed Central

    Moll, Gert N.; Konings, Wil N.; Driessen, Arnold J. M.

    1998-01-01

    Nisin is a pore-forming antimicrobial peptide. The capacity of nisin to induce transmembrane movement of a fluorescent phospholipid in lipid vesicles was investigated. Unilamellar phospholipid vesicles that contained a fluorescent phospholipid (1-acyl-2-{6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]caproyl}-sn-glycero-3-phosphocholine) in the inner leaflet of the bilayer were used. Nisin-induced movement of the fluorescent phospholipid from the inner leaflet to the outer leaflet of the membrane reached stable levels, which were dependent on the concentration of nisin added. The rate constant k of this nisin-induced transmembrane movement increased with the nisin concentration but was not dependent on temperature within the range of 5 to 30°C. In contrast, the rate constant of movement of fluorescent phospholipid from vesicle to vesicle strongly depended on temperature. The data indicate that nisin transiently disturbs the phospholipid organization of the target membrane. PMID:9852000

  6. Inositol 1,3,4,5-tetrakisphosphate and not phosphatidylinositol 3,4-bisphosphate is the probable precursor of inositol 1,3,4-trisphosphate in agonist-stimulated parotid gland.

    PubMed Central

    Downes, C P; Hawkins, P T; Irvine, R F

    1986-01-01

    When [3H]inositol-prelabelled rat parotid-gland slices were stimulated with carbachol, noradrenaline or Substance P, the major inositol trisphosphate produced with prolonged exposure to agonists was, in each case, inositol 1,3,4-trisphosphate. Much lower amounts of radioactivity were present in the inositol 1,4,5-trisphosphate fraction separated by anion-exchange h.p.l.c. Analysis of the inositol trisphosphate head group of phosphatidylinositol bisphosphate in [32P]Pi-labelled parotid glands showed the presence of phosphatidylinositol 4,5-bisphosphate, but no detectable phosphatidylinositol 3,4-bisphosphate. Carbachol-stimulated [3H]inositol-labelled parotid glands contained an inositol polyphosphate with the chromatographic properties and electrophoretic mobility of an inositol tetrakisphosphate, the probable structure of which was determined to be inositol 1,3,4,5-tetrakisphosphate. Since an enzyme in erythrocyte membranes is capable of degrading this tetrakisphosphate to inositol 1,3,4-trisphosphate, it is suggested to be the precursor of inositol 1,3,4-trisphosphate in parotid glands. PMID:2432882

  7. Phospholipid methylation in starfish spermatozoa is linked to sperm chemoattraction.

    PubMed Central

    Tezon, J; Miller, R L; Bardin, C W

    1986-01-01

    The mechanism whereby ovarian peptides cause sperm attraction was studied in the starfish. Phospholipid methylation and protein-O-carboxyl methylation, reactions linked to chemotactic responses in a variety of systems, were studied in starfish sperm. When sperm were preincubated with [methyl-3H]methionine and then exposed to the attractant, a rapid drop in radioactivity occurred in the phospholipid fraction. Methylated phospholipids decreased by 90% in the first 2 sec; however, no change was observed in endogenous methylation of protein carboxyl groups. The effect on phospholipid methylation was dose dependent, with a 40% reduction in radioactive phospholipids in sperm occurring with the minimal amount of attractant necessary to obtain a positive response in a sperm attraction bioassay. Attractants from species of starfish with little or no cross-reactivity in the bioassay had a limited effect on phospholipid methylation. The transmethylase inhibitor, homocysteine, caused a marked decrease in the accumulation of methylated phospholipids under basal conditions, which was correlated with as much as a 50-fold increase in sperm sensitivity to the attractant. The addition of chemoattractant resulted in a reduction in the amount of all individual methylated phospholipids, but the amount of phosphatidylmono[3H]methylethanolamine relative to the other methylated phospholipid decreased by a factor of 4 after stimulation. Homocysteine had the same effect. The reduction in methylated phospholipids by attractants suggests that phospholipid methylation is linked to the mechanism of action of these peptides. Methylation of phospholipids may play a role in the rapid desensitization of sperm cells to the attractant, which would be required for the orientation of the spermatozoa in the gradient of ovarian peptide. PMID:3459145

  8. Specific determination of myo-inositol in multivitamin pharmaceutical preparations by a flow injection system using a myo-inositol dehydrogenase reactor coupled with a glucose eliminating enzyme reactor.

    PubMed

    Ono, Masaki; Nakajima, Toshiaki; Itoh, Yuji; Shimada, Kenji; Yamato, Susumu

    2003-12-04

    A flow injection system for myo-inositol determination in multivitamin pharmaceutical preparations using two enzyme reactors was developed. Myo-inositol was detected using a fluorophotometer, to measure the fluorescence of NADH produced from NAD+ by a myo-inositol dehydrogenase reactor (IDR) containing myo-inositol dehydrogenase immobilized on porous glass. Enhanced interference due to excess glucose included in a multivitamin pharmaceutical preparation as a sweetener was eliminated by a glucose eliminating reactor (GER) co-immobilized with three enzymes (glucose oxidase, mutarotase and catalase). The calibration coefficient for the standard curve was 0.9993 for myo-inositol detection in the range of 1-5 microg/ml. Myo-inositol was determined even in the presence of glucose concentrations of 140-420 microg/ml. The recovery of myo-inositol added to the multivitamin pharmaceutical preparation was 99.6% (n=9).

  9. Phospholipid biosynthesis and solvent tolerance in Pseudomonas putida strains.

    PubMed

    Pinkart, H C; White, D C

    1997-07-01

    The role of the cell envelope in the solvent tolerance mechanisms of Pseudomonas putida was investigated. The responses of a solvent-tolerant strain, P. putida Idaho, and a solvent-sensitive strain, P. putida MW1200, were examined in terms of phospholipid content and composition and of phospholipid biosynthetic rate following exposure to a nonmetabolizable solvent, o-xylene. Following o-xylene exposure, P. putida MW1200 exhibited a decrease in total phospholipid content. In contrast, P. putida Idaho demonstrated an increase in phospholipid content 1 to 6 h after exposure. Analysis of phospholipid biosynthesis showed P. putida Idaho to have a higher basal rate of phospholipid synthesis than MW1200. This rate increased significantly following exposure to xylene. Both strains showed little significant turnover of phospholipid in the absence of xylene. In the presence of xylene, both strains showed increased phospholipid turnover. The rate of turnover was significantly greater in P. putida Idaho than in P. putida MW1200. These results suggest that P. putida Idaho has a greater ability than the solvent-sensitive strain MW1200 to repair damaged membranes through efficient turnover and increased phospholipid biosynthesis.

  10. Phospholipid biosynthesis and solvent tolerance in Pseudomonas putida strains.

    PubMed Central

    Pinkart, H C; White, D C

    1997-01-01

    The role of the cell envelope in the solvent tolerance mechanisms of Pseudomonas putida was investigated. The responses of a solvent-tolerant strain, P. putida Idaho, and a solvent-sensitive strain, P. putida MW1200, were examined in terms of phospholipid content and composition and of phospholipid biosynthetic rate following exposure to a nonmetabolizable solvent, o-xylene. Following o-xylene exposure, P. putida MW1200 exhibited a decrease in total phospholipid content. In contrast, P. putida Idaho demonstrated an increase in phospholipid content 1 to 6 h after exposure. Analysis of phospholipid biosynthesis showed P. putida Idaho to have a higher basal rate of phospholipid synthesis than MW1200. This rate increased significantly following exposure to xylene. Both strains showed little significant turnover of phospholipid in the absence of xylene. In the presence of xylene, both strains showed increased phospholipid turnover. The rate of turnover was significantly greater in P. putida Idaho than in P. putida MW1200. These results suggest that P. putida Idaho has a greater ability than the solvent-sensitive strain MW1200 to repair damaged membranes through efficient turnover and increased phospholipid biosynthesis. PMID:9209036

  11. Looking beyond structure: membrane phospholipids of skeletal muscle mitochondria

    PubMed Central

    Heden, Timothy D.; Neufer, P. Darrell; Funai, Katsuhiko

    2016-01-01

    Skeletal muscle mitochondria are highly dynamic and capable of tremendous expansion to meet cellular energetic demands. Such proliferation in mitochondrial mass requires a synchronized supply of enzymes and structural phospholipids. While transcriptional regulation of mitochondrial enzymes has been extensively studied, there is limited information on how mitochondrial membrane lipids are generated in skeletal muscle. Herein we describe how each class of phospholipids that constitute mitochondrial membranes are synthesized and/or imported, and summarize genetic evidence indicating that membrane phospholipid composition represents a significant modulator of skeletal muscle mitochondrial respiratory function. We also discuss how skeletal muscle mitochondrial phospholipids may mediate the effect of diet and exercise on oxidative metabolism. PMID:27370525

  12. Loss-of-function of inositol polyphosphate-4-phosphatase reversibly increases the severity of allergic airway inflammation.

    PubMed

    Aich, Jyotirmoi; Mabalirajan, Ulaganathan; Ahmad, Tanveer; Agrawal, Anurag; Ghosh, Balaram

    2012-06-06

    Inositol polyphosphate phosphatases regulate the magnitude of phosphoinositide-3 kinase signalling output. Although inositol polyphosphate-4-phosphatase is known to regulate phosphoinositide-3 kinase signalling, little is known regarding its role in asthma pathogenesis. Here we show that modulation of inositol polyphosphate-4-phosphatase alters the severity of asthma. Allergic airway inflammation in mice led to calpain-mediated degradation of inositol polyphosphate-4-phosphatase. In allergic airway inflammation models, preventing inositol polyphosphate-4-phosphatase degradation by inhibiting calpain activity, or overexpression of inositol polyphosphate-4-phosphatase in mouse lungs, led to attenuation of the asthma phenotype. Conversely, knockdown of inositol polyphosphate-4-phosphatase severely aggravated the allergic airway inflammation and the asthma phenotype. Interestingly, inositol polyphosphate-4-phosphatase knockdown in lungs of naive mice led to spontaneous airway hyper-responsiveness, suggesting that inositol polyphosphate-4-phosphatase could be vital in maintaining the lung homeostasis. We suggest that inositol polyphosphate-4-phosphatase has an important role in modulating inflammatory response in asthma, and thus, uncover a new understanding of the complex interplay between inositol signalling and asthma, which could provide alternative strategies in asthma management.

  13. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES Treatment of Excess Distributions of Trusts Applicable to Taxable Years Beginning Before January 1, 1969 § 1.665(e)-1 Preceding taxable year. (a) Definition. For purposes of subpart D...

  14. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of this...

  15. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of this...

  16. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of this...

  17. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of this...

  18. 10 CFR 501.10 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Order of precedence. 501.10 Section 501.10 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 501.10 Order of precedence. If there is any conflict or inconsistency between the provisions of this...

  19. Phospholipid biosynthetic enzymes in human brain.

    PubMed

    Ross, B M; Moszczynska, A; Blusztajn, J K; Sherwin, A; Lozano, A; Kish, S J

    1997-04-01

    Growing evidence suggests an involvement of brain membrane phospholipid metabolism in a variety of neurodegenerative and psychiatric conditions. This has prompted the use of drugs (e.g., CDPcholine) aimed at elevating the rate of neural membrane synthesis. However, no information is available regarding the human brain enzymes of phospholipid synthesis which these drugs affect. Thus, the objective of our study was to characterize the enzymes involved, in particular, whether differences existed in the relative affinity of substrates for the enzymes of phosphatidylethanolamine (PE) compared to those of phosphatidylcholine (PC) synthesis. The concentration of choline in rapidly frozen human brain biopsies ranged from 32-186 nmol/g tissue, a concentration similar to that determined previously for ethanolamine. Since human brain ethanolamine kinase possessed a much lower affinity for ethanolamine (Km = 460 microM) than choline kinase did for choline (Km = 17 microM), the activity of ethanolamine kinase in vivo may be more dependent on substrate availability than that of choline kinase. In addition, whereas ethanolamine kinase was inhibited by choline, and to a lesser extent by phosphocholine, choline kinase activity was unaffected by the presence of ethanolamine, or phosphoethanolamine, and only weakly inhibited by phosphocholine. Phosphoethanolamine cytidylyltransferase (PECT) and phosphocholine cytidylyltransferase (PCCT) also displayed dissimilar characteristics, with PECT and PCCT being located predominantly in the cytosolic and particulate fractions, respectively. Both PECT and PCCT exhibited a low affinity for CTP (Km approximately 1.2 mM), suggesting that the activities of these enzymes, and by implication, the rate of phospholipid synthesis, are highly dependent upon the cellular concentration of CTP. In conclusion our data indicate different regulatory properties of PE and PC synthesis in human brain, and suggest that the rate of PE synthesis may be more

  20. Changes in inositol phosphates in wild carrot cells upon initiation of cell wall digestion

    SciTech Connect

    Rincon, M.; Boss, W.F.

    1987-04-01

    Previous studies have shown that inositol trisphosphate (IP/sub 3/) stimulated /sup 45/Ca/sup +2/ efflux from fusogenic carrot protoplasts and it was suggested that IP/sub 3/ may serve as a second messenger for the mobilization of intracellular Ca/sup +2/ in higher plant cells. To determine whether or not inositol phosphate metabolism changes in response to external stimuli, the cells were labeled with myo-(2-/sup 3/H) inositol for 18 h and exposed to cell wall digestion enzymes, Driselase. The inositol phosphates were extracted with ice cold 10% TCA and separated by anion exchange chromatography. The radioactivity of the fraction that contained IP/sub 3/ increased 2-3.8 fold and that which contained inositol bisphosphate increased 1.9-2.6 fold within 1.5 min of exposure to Driselase. After 6 min, the radioactivity of both fractions increased 6-7.7 fold and an increase in inositol monophosphate was observed. These data indicate that inositol phosphate metabolism is stimulated by Driselase and suggest polyphosphoinositide hydrolysis occurs upon initiation of cell wall digestion.

  1. D-chiro-inositol--its functional role in insulin action and its deficit in insulin resistance.

    PubMed

    Larner, Joseph

    2002-01-01

    In this review we discuss the biological significance of D-chiro-inositol, originally discovered as a component of a putative mediator of intracellular insulin action, where as a putative mediator, it accelerates the dephosphorylation of glycogen synthase and pyruvate dehydrogenase, rate limiting enzymes of non-oxidative and oxidative glucose disposal. Early studies demonstrated a linear relationship between its decreased urinary excretion and the degree of insulin resistance present. When tissue contents, including muscle, of type 2 diabetic subjects were assayed, they demonstrated a more general body deficiency. Administration of D-chiro-inositol to diabetic rats, Rhesus monkeys and now to humans accelerated glucose disposal and sensitized insulin action. A defect in vivo in the epimerization of myo-inositol to chiro-inositol in insulin sensitive tissues of the GK type 2 diabetic rat has been elucidated. Thus, administered D-chiro-inositol may act to bypass a defective normal epimerization of myo-inositol to D-chiro-inositol associated with insulin resistance and act to at least partially restore insulin sensitivity and glucose disposal.

  2. Effect of Treating Streptozotocin-Induced Diabetic Rats With Sorbinil, Myo-Inositol or Aminoguanidine on Endoneurial Blood Flow, Motor Nerve Conduction Velocity and Vascular Function of Epineurial Arterioles of the Sciatic Nerve

    PubMed Central

    Coppey, Lawrence J.; Gellett, Jill S.; Davidson, Eric P.; Dunlap, Joyce A.

    2002-01-01

    Previously we have demonstrated that diabetes causes impairment in vascular function of epineurial vessels, which precedes the slowing of motor nerve conduction velocity. Treatment of diabetic rats with aldose reductase inhibitors, aminoguanidine or myo-inositol supplementation have been shown to improve motor nerve conduction velocity and/or decreased endoneurial blood flow. However, the effect these treatments have on vascular reactivity of epineurial vessels of the sciatic nerve is unknown. In these studies we examined the effect of treating streptozotocininduced rats with sorbinil, aminoguanidine or myo-inositol on motor nerve conduction velocity, endoneurial blood flow and endothelium dependent vascular relaxation of arterioles that provide circulation to the region of the sciatic nerve. Treating diabetic rats with sorbinil, aminoguanidine or myo-inositol improved the reduction of endoneurial blood flow and motor nerve conduction velocity. However, only sorbinil treatment significantly improved the diabetes-induced impairment of acetylcholinemediated vasodilation of epineurial vessels of the sciatic nerve. All three treatments were efficacious in preventing the appropriate metabolic derangements associated with either activation of the polyol pathway or increased nonenzymatic glycation. In addition, sorbinil was shown to prevent the diabetes-induced decrease in lens glutathione level. However, other markers of oxidative stress were not vividly improved by these treatments. These studies suggest that sorbinil treatment may be more effective in preventing neural dysfunction in diabetes than either aminoguanidine or myoinositol. PMID:11900277

  3. Dietary Phospholipids and Intestinal Cholesterol Absorption

    PubMed Central

    Cohn, Jeffrey S.; Kamili, Alvin; Wat, Elaine; Chung, Rosanna W. S.; Tandy, Sally

    2010-01-01

    Experiments carried out with cultured cells and in experimental animals have consistently shown that phospholipids (PLs) can inhibit intestinal cholesterol absorption. Limited evidence from clinical studies suggests that dietary PL supplementation has a similar effect in man. A number of biological mechanisms have been proposed in order to explain how PL in the gut lumen is able to affect cholesterol uptake by the gut mucosa. Further research is however required to establish whether the ability of PLs to inhibit cholesterol absorption is of therapeutic benefit. PMID:22254012

  4. Phospholipid and sphingolipid metabolism in Leishmania

    PubMed Central

    Zhang, Kai; Beverley, Stephen M.

    2009-01-01

    In many eukaryotes, phospholipids (PLs) and sphingolipids (SLs) are abundant membrane components and reservoirs for important signaling molecules. In Leishmania, the composition, metabolism, and function of PLs and SLs differ significantly from those in mammalian cells. Although only a handful of enzymes have been experimentally characterized, available data suggest many steps of PL/SL metabolism are critical for Leishmania viability and/or virulence, and could be a source for new drug targets. Further studies of genes involved in the synthesis (de novo and salvage) and degradation of PLs and SLs will reveal their diverse effects on Leishmania pathogenesis. PMID:20026359

  5. Membrane phospholipid asymmetry in human thalassemia.

    PubMed

    Kuypers, F A; Yuan, J; Lewis, R A; Snyder, L M; Kiefer, C R; Bunyaratvej, A; Fucharoen, S; Ma, L; Styles, L; de Jong, K; Schrier, S L

    1998-04-15

    Phospholipid asymmetry in the red blood cell (RBC) lipid bilayer is well maintained during the life of the cell, with phosphatidylserine (PS) virtually exclusively located in the inner monolayer. Loss of phospholipid asymmetry, and consequently exposure of PS, is thought to play an important role in red cell pathology. The anemia in the human thalassemias is caused by a combination of ineffective erythropoiesis (intramedullary hemolysis) and a decreased survival of adult RBCs in the peripheral blood. This premature destruction of the thalassemic RBC could in part be due to a loss of phospholipid asymmetry, because cells that expose PS are recognized and removed by macrophages. In addition, PS exposure can play a role in the hypercoagulable state reported to exist in severe beta-thalassemia intermedia. We describe PS exposure in RBCs of 56 comparably anemic patients with different genetic backgrounds of the alpha- or beta-thalassemia phenotype. The use of fluorescently labeled annexin V allowed us to determine loss of phospholipid asymmetry in individual cells. Our data indicate that in a number of thalassemic patients, subpopulations of red cells circulate that expose PS on their outer surface. The number of such cells can vary dramatically from patient to patient, from as low as that found in normal controls (less than 0.2%) up to 20%. Analysis by fluorescent microscopy of beta-thalassemic RBCs indicates that PS on the outer leaflet is distributed either over the entire membrane or localized in areas possibly related to regions rich in membrane-bound alpha-globin chains. We hypothesize that these membrane sites in which iron carrying globin chains accumulate and cause oxidative damage, could be important in the loss of membrane lipid organization. In conclusion, we report the presence of PS-exposing subpopulations of thalassemic RBC that are most likely physiologically important, because they could provide a surface for enhancing hemostasis as recently reported

  6. Protein-phospholipid interactions in blood clotting.

    PubMed

    Morrissey, James H; Davis-Harrison, Rebecca L; Tavoosi, Narjes; Ke, Ke; Pureza, Vincent; Boettcher, John M; Clay, Mary C; Rienstra, Chad M; Ohkubo, Y Zenmei; Pogorelov, Taras V; Tajkhorshid, Emad

    2010-04-01

    Most steps of the blood clotting cascade require the assembly of a serine protease with its specific regulatory protein on a suitable phospholipid bilayer. Unfortunately, the molecular details of how blood clotting proteins bind to membrane surfaces remain poorly understood, owing to a dearth of techniques for studying protein-membrane interactions at high resolution. Our laboratories are tackling this question using a combination of approaches, including nanoscale membrane bilayers, solid-state NMR, and large-scale molecular dynamics simulations. These studies are now providing structural insights at atomic resolution into clotting protein-membrane interactions. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  7. Protein-Phospholipid Interactions in Blood Clotting

    PubMed Central

    Morrissey, James H.; Davis-Harrison, Rebecca L.; Tavoosi, Narjes; Ke, Ke; Pureza, Vincent; Boettcher, John M.; Clay, Mary C.; Rienstra, Chad M.; Ohkubo, Y. Zenmei; Pogorelov, Taras V.; Tajkhorshid, Emad

    2010-01-01

    Most steps of the blood clotting cascade require the assembly of a serine protease with its specific regulatory protein on a suitable phospholipid bilayer. Unfortunately, the molecular details of how blood clotting proteins bind to membrane surfaces remain poorly understood, owing to a dearth of techniques for studying protein-membrane interactions at high resolution. Our laboratories are tackling this question using a combination of approaches, including nanoscale membrane bilayers, solid-state NMR, and large-scale molecular dynamics simulations. These studies are now providing structural insights at atomic resolution into clotting protein-membrane interactions. PMID:20129649

  8. Inositol for the prevention of neural tube defects: a pilot randomised controlled trial.

    PubMed

    Greene, Nicholas D E; Leung, Kit-Yi; Gay, Victoria; Burren, Katie; Mills, Kevin; Chitty, Lyn S; Copp, Andrew J

    2016-03-28

    Although peri-conceptional folic acid (FA) supplementation can prevent a proportion of neural tube defects (NTD), there is increasing evidence that many NTD are FA non-responsive. The vitamin-like molecule inositol may offer a novel approach to preventing FA-non-responsive NTD. Inositol prevented NTD in a genetic mouse model, and was well tolerated by women in a small study of NTD recurrence. In the present study, we report the Prevention of Neural Tube Defects by Inositol (PONTI) pilot study designed to gain further experience of inositol usage in human pregnancy as a preliminary trial to a future large-scale controlled trial to evaluate efficacy of inositol in NTD prevention. Study subjects were UK women with a previous NTD pregnancy who planned to become pregnant again. Of 117 women who made contact, ninety-nine proved eligible and forty-seven agreed to be randomised (double-blind) to peri-conceptional supplementation with inositol plus FA or placebo plus FA. In total, thirty-three randomised pregnancies produced one NTD recurrence in the placebo plus FA group (n 19) and no recurrences in the inositol plus FA group (n 14). Of fifty-two women who declined randomisation, the peri-conceptional supplementation regimen and outcomes of twenty-two further pregnancies were documented. Two NTD recurred, both in women who took only FA in their next pregnancy. No adverse pregnancy events were associated with inositol supplementation. The findings of the PONTI pilot study encourage a large-scale controlled trial of inositol for NTD prevention, but indicate the need for a careful study design in view of the unwillingness of many high-risk women to be randomised.

  9. Transport and metabolism of indole-3-acetyl-myo-inositol-galactoside in seedlings of Zea mays

    NASA Technical Reports Server (NTRS)

    Komoszynski, M.; Bandurski, R. S.

    1986-01-01

    Indole-3-acetyl-myo-inositol galactoside labeled with 3H in the indole and 14C in the galactose moieties was applied to kernels of 5 day old germinating seedlings of Zea mays. Indole-3-acetyl-myo-inositol galactoside was not transported into either the shoot or root tissue as the intact molecule but was instead hydrolyzed to yield [3H]indole-3-acetyl-myo-inositol and [3H]indole-3-acetic acid which were then transported to the shoot with little radioactivity going to the root. With certain assumption concerning the equilibration of applied [3H]indole-3-acetyl-myo-inositol-[U-14C]galactose with the endogenous pool, it may be concluded that indole-3-acetyl-myo-inositol galactoside in the endosperm supplies about 2 picomoles per plant per hour of indole-3-acetyl-myo-inositol and 1 picomole per plant per hour of indole-3-acetic acid to the shoot and thus is comparable to indole-3-acetyl-myo-inositol as a source of indole-acetic acid for the shoot. Quantitative estimates of the amount of galactose in the kernels suggest that [3H]indole-3-acetyl-myo-inositol-[14C]galactose is hydrolyzed after the compound leaves the endosperm but before it reaches the shoot. In addition, [3H]indole-3-acetyl-myo-inositol-[14C]galactose supplies appreciable amounts of 14C to the shoot and both 14C and 3H to an uncharacterized insoluble fraction of the endosperm.

  10. Inositol pyrophosphates modulate cell cycle independently of alteration in telomere length.

    PubMed

    Banfic, Hrvoje; Crljen, Vladiana; Lukinovic-Skudar, Vesna; Dembitz, Vilma; Lalic, Hrvoje; Bedalov, Antonio; Visnjic, Dora

    2016-01-01

    Synthesis of inositol pyrophosphates through activation of Kcs1 plays an important role in the signalling response required for cell cycle progression after mating pheromone arrest. Overexpression of Kcs1 doubled the level of inositol pyrophosphates when compared to wild type cells and 30 min following the release from α-factor block further increase in inositol pyrophosphates was observed, which resulted that cells overexpressing Kcs1 reached G2/M phase earlier than wild type cells. Similar effect was observed in ipk1Δ cells, which are unable to synthesize IP6-derived inositol pyrophosphates (IP7 and IP8) but will synthesize IP5-derived inositol pyrophosphates (PP-IP4 and (PP)2-IP3). Although ipk1Δ cells have shorter telomeres than wild type cells, overexpression of Kcs1 in both strains have similar effect on cell cycle progression. As it is known that PP-IP4 regulates telomere length through Tel1, inositol polyphosphates, cell cycle and telomere length were determined in tel1Δ cells. The release of the cells from α-factor block and overexpression of Kcs1 in tel1Δ cells produced similar effects on inositol pyrophosphates level and cell cycle progression when compared to wild type cells, although tel1Δ cells possesses shorter telomeres than wild type cells. It can be concluded that telomere length does not affect cell cycle progression, since cells with short telomeres (ipk1Δ and tel1Δ) progress through cell cycle in a similar manner as wild type cells and that overexpression of Kcs1 in cells with either short or normal telomeres will increase S phase progression without affecting telomere length. Furthermore, IP5-derived inositol pyrophosphates can compensate for the loss of IP6-derived inositol pyrophosphates, in modulating S phase progression of the cell cycle.

  11. Transport and metabolism of indole-3-acetyl-myo-inositol-galactoside in seedlings of Zea mays

    NASA Technical Reports Server (NTRS)

    Komoszynski, M.; Bandurski, R. S.

    1986-01-01

    Indole-3-acetyl-myo-inositol galactoside labeled with 3H in the indole and 14C in the galactose moieties was applied to kernels of 5 day old germinating seedlings of Zea mays. Indole-3-acetyl-myo-inositol galactoside was not transported into either the shoot or root tissue as the intact molecule but was instead hydrolyzed to yield [3H]indole-3-acetyl-myo-inositol and [3H]indole-3-acetic acid which were then transported to the shoot with little radioactivity going to the root. With certain assumption concerning the equilibration of applied [3H]indole-3-acetyl-myo-inositol-[U-14C]galactose with the endogenous pool, it may be concluded that indole-3-acetyl-myo-inositol galactoside in the endosperm supplies about 2 picomoles per plant per hour of indole-3-acetyl-myo-inositol and 1 picomole per plant per hour of indole-3-acetic acid to the shoot and thus is comparable to indole-3-acetyl-myo-inositol as a source of indole-acetic acid for the shoot. Quantitative estimates of the amount of galactose in the kernels suggest that [3H]indole-3-acetyl-myo-inositol-[14C]galactose is hydrolyzed after the compound leaves the endosperm but before it reaches the shoot. In addition, [3H]indole-3-acetyl-myo-inositol-[14C]galactose supplies appreciable amounts of 14C to the shoot and both 14C and 3H to an uncharacterized insoluble fraction of the endosperm.

  12. Novel catecholate-type siderophore analogs based on a myo-inositol scaffold.

    PubMed

    Schnabelrauch, M; Egbe, D A; Heinisch, L; Reissbrodt, R; Möllmann, U

    1998-09-01

    A novel 1,3,5-triamino-myo-inositol derivative is presented as a readily available scaffold for the design of tripodal siderophore mimetics. Based on this scaffold, various hexadentate catecholate-type siderophore analogs were synthesized by attaching the catechols to the inositol scaffold via spacer units of different structure and length. The potential to tune the polarity of the inositol containing siderophore analogs has also been demonstrated by varying the protection group strategy. The siderophore activity of the prepared siderophore analogs was examined by cross-feeding tests with various Gram-negative bacteria and mycobacteria.

  13. Antibiotic Resistance Associated with Inositol Metabolism in Salmonellae from Ontario Cattle

    PubMed Central

    Lynch, John A.; Kierstead, Marsha E.

    1985-01-01

    During 12 months in 1983-1984, Salmonellae were isolated from cattle 110 times. Salmonella typhimurium and Salmonella muenster were the most prevalent serotypes identified. All isolates were sensitive to polymyxin B. Isolates that did not produce acid from inositol were more frequently resistant to ampicillin, carbenicillin, kanamycin, sulfisoxazole, tetracycline and neomycin than isolates which could. Salmonella muenster isolates, which were almost exclusively inositol positive, demonstrated a high frequency of senstivity to commonly used antibiotics. The antibiotic sensitivities of the S. typhimurium isolates showed much greater variability, with multiple antibiotic resistance being frequently associated with those isolates that were inositol negative. PMID:17422563

  14. Design and Synthesis of an Inositol Phosphate Analog Based on Computational Docking Studies.

    PubMed

    Peng, Zhenghong; Maxwell, David; Sun, Duoli; Ying, Yunming; Schuber, Paul T; Bhanu Prasad, Basvoju A; Gelovani, Juri; Yung, Wai-Kwan Alfred; Bornmann, William G

    2014-01-28

    A virtual library of 54 inositol analog mimics of In(1,4,5)P3 has been docked, scored, and ranked within the binding site of human inositol 1,4,5-trisphosphate 3-kinase A (IP3-3KA). Chemical synthesis of the best scoring structure that also met distance criteria for 3'-OH to -P in Phosphate has been attempted along with the synthesis of (1S,2R,3S,4S)-3-fluoro-2,4-dihydroxycyclohexanecarboxylic acid as an inositol analog, useful for non-invasive visualization and quantitation of IP3-3KA enzymatic activity.

  15. Low phospholipid-associated cholestasis and cholelithiasis.

    PubMed

    Erlinger, Serge

    2012-09-01

    Low phospholipid-associated cholestasis and cholelithiasis (LPAC) is a genetic disorder characterized by cholesterol gallbladder and intrahepatic stones. It is caused by a mutation of the gene ABCB4, which encodes the canalicular protein ABCB4/MDR3, a flippase that plays an essential role in the secretion of phosphatidylcholine into bile. Failure of this protein leads to secretion of bile that is poor in phospholipids and, hence, highly lithogenic, with potent detergent properties. This, in turn, leads to cholangiocyte luminal membrane injury and biliary lesions causing cholestasis. The diagnosis should be suspected when at least two of the following criteria are present: onset of symptoms before the age of 40 years; recurrence of biliary symptoms (biliary colic, jaundice, cholangitis, acute pancreatitis) after cholecystectomy; presence of echogenic foci within the liver indicative of intrahepatic stones or biliary sludge; previous episode(s) of intrahepatic cholestasis of pregnancy; and family history of gallstones in first-degree relatives. Intrahepatic stones can be demonstrated by ultrasonography with color Doppler examination, computed tomography and magnetic resonance imaging with magnetic resonance cholangiography, and the diagnosis confirmed by ABCB4 genotyping. Therapy with ursodeoxycholic acid offers prompt relief of symptoms and usually prevents complications. In some cases, however, surgery may be necessary. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  16. Dihydrolipoyl dioleoylglycerol antioxidant capacity in phospholipid vesicles.

    PubMed

    Laszlo, Joseph A; Evans, Kervin O; Compton, David L; Appell, Michael

    2012-02-01

    Antioxidants have critical roles in maintaining cellular homeostasis and disease-state prevention. The multi-functional agent α-lipoic acid offers numerous beneficial effects to oxidatively stressed tissues. α-Lipoic acid was enzymatically incorporated into a triglyceride in conjunction with oleic acid, creating lipoyl dioleoylglycerol, and chemically reduced to form dihydrolipoyl dioleoylglycerol. The triglyceride forms of lipoic acid stabilized dioleoylphosphatidylcholine unilamellar liposomal vesicles, as judged by calcein-cobalt leakage. Stabilization resulted from increased packing density of phospholipid acyl chains. Scavenging activity against the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) radical was monitored by oxidation of 4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C(11)-Bodipy). Dihydrolipoyl dioleoylglycerol in vesicles demonstrated strong antioxidant capacity in comparison to the conventional Trolox standard. Fluorescence quenching measurements indicated the lipoyl moiety of dihydrolipoyl dioleoylglycerol is positioned near the vesicle aqueous/lipid boundary. Treatment of intact vesicles with a nonpenetrating sulfhydryl reagent indicated that 80% of the dihydrolipoyl dioleoylglycerol was available for reaction. Molecular modeling of lipoyl dioleoylglycerol and dihydrolipoyl dioleoylglycerol in a phospholipid layer confirmed the existence of an extended configuration for the molecules that accounts for the interfacial location of the lipoyl moiety, which may allow the antioxidant to readily react with radical species approaching membranes from the aqueous phase. Published by Elsevier Ireland Ltd.

  17. Phospholipid imprinted polymers as selective endotoxin scavengers

    NASA Astrophysics Data System (ADS)

    Sulc, Robert; Szekely, Gyorgy; Shinde, Sudhirkumar; Wierzbicka, Celina; Vilela, Filipe; Bauer, David; Sellergren, Börje

    2017-03-01

    Herein we explore phospholipid imprinting as a means to design receptors for complex glycolipids comprising the toxic lipopolysaccharide endotoxin. A series of polymerizable bis-imidazolium and urea hosts were evaluated as cationic and neutral hosts for phosphates and phosphonates, the latter used as mimics of the phospholipid head groups. The bis-imidazolium hosts interacted with the guests in a cooperative manner leading to the presence of tight and well defined 1:2 ternary complexes. Optimized monomer combinations were subsequently used for imprinting of phosphatidic acid as an endotoxin dummy template. Presence of the aforementioned ternary complexes during polymerization resulted in imprinting of lipid dimers – the latter believed to crudely mimic the endotoxin Lipid A motif. The polymers were characterized with respect to template rebinding, binding affinity, capacity and common structural properties, leading to the identification of polymers which were thereafter subjected to an industrially validated endotoxin removal test. Two of the polymers were capable of removing endotoxin down to levels well below the accepted threshold (0.005 EU/mg API) in pharmaceutical production.

  18. Phospholipid imprinted polymers as selective endotoxin scavengers

    PubMed Central

    Sulc, Robert; Szekely, Gyorgy; Shinde, Sudhirkumar; Wierzbicka, Celina; Vilela, Filipe; Bauer, David; Sellergren, Börje

    2017-01-01

    Herein we explore phospholipid imprinting as a means to design receptors for complex glycolipids comprising the toxic lipopolysaccharide endotoxin. A series of polymerizable bis-imidazolium and urea hosts were evaluated as cationic and neutral hosts for phosphates and phosphonates, the latter used as mimics of the phospholipid head groups. The bis-imidazolium hosts interacted with the guests in a cooperative manner leading to the presence of tight and well defined 1:2 ternary complexes. Optimized monomer combinations were subsequently used for imprinting of phosphatidic acid as an endotoxin dummy template. Presence of the aforementioned ternary complexes during polymerization resulted in imprinting of lipid dimers – the latter believed to crudely mimic the endotoxin Lipid A motif. The polymers were characterized with respect to template rebinding, binding affinity, capacity and common structural properties, leading to the identification of polymers which were thereafter subjected to an industrially validated endotoxin removal test. Two of the polymers were capable of removing endotoxin down to levels well below the accepted threshold (0.005 EU/mg API) in pharmaceutical production. PMID:28303896

  19. Generation and Biological Activities of Oxidized Phospholipids

    PubMed Central

    Oskolkova, Olga V.; Birukov, Konstantin G.; Levonen, Anna-Liisa; Binder, Christoph J.; Stöckl, Johannes

    2010-01-01

    Abstract Glycerophospholipids represent a common class of lipids critically important for integrity of cellular membranes. Oxidation of esterified unsaturated fatty acids dramatically changes biological activities of phospholipids. Apart from impairment of their structural function, oxidation makes oxidized phospholipids (OxPLs) markers of “modified-self” type that are recognized by soluble and cell-associated receptors of innate immunity, including scavenger receptors, natural (germ line-encoded) antibodies, and C-reactive protein, thus directing removal of senescent and apoptotic cells or oxidized lipoproteins. In addition, OxPLs acquire novel biological activities not characteristic of their unoxidized precursors, including the ability to regulate innate and adaptive immune responses. Effects of OxPLs described in vitro and in vivo suggest their potential relevance in different pathologies, including atherosclerosis, acute inflammation, lung injury, and many other conditions. This review summarizes current knowledge on the mechanisms of formation, structures, and biological activities of OxPLs. Furthermore, potential applications of OxPLs as disease biomarkers, as well as experimental therapies targeting OxPLs, are described, providing a broad overview of an emerging class of lipid mediators. Antioxid. Redox Signal. 12, 1009–1059. PMID:19686040

  20. Nuclear inositol lipid metabolism: more than just second messenger generation?

    PubMed

    Martelli, Alberto M; Follo, Matilde Yung; Evangelisti, Camilla; Falà, Federica; Fiume, Roberta; Billi, Anna Maria; Cocco, Lucio

    2005-10-01

    A distinct polyphosphoinositide cycle is present in the nucleus, and growing evidence suggests its importance in DNA replication, gene transcription, and apoptosis. Even though it was initially thought that nuclear inositol lipids would function as a source for second messengers, recent findings strongly indicate that lipids present in the nucleus also fulfil other roles. The scope of this review is to highlight the most intriguing advances made in the field over the last few years, such as the possibility that nuclear phosphatidylinositol (4,5) bisphosphate is involved in maintaining chromatin in a transcriptionally active conformation, the new emerging roles for intranuclear phosphatidylinositol (3,4,5) trisphosphate and phosphoinositide 3-kinase, and the evidence which suggests a tight relationship between a decreased level of nuclear phosphoinositide specific phospholipase C-beta1 and the evolution of myelodisplastic syndrome into acute myeloid leukemia.

  1. Inositol 5-phosphatases: insights from the Lowe syndrome protein OCRL.

    PubMed

    Pirruccello, Michelle; De Camilli, Pietro

    2012-04-01

    The precise regulation of phosphoinositide lipids in cellular membranes is crucial for cellular survival and function. Inositol 5-phosphatases have been implicated in a variety of disorders, including various cancers, obesity, type 2 diabetes, neurodegenerative diseases and rare genetic conditions. Despite the obvious impact on human health, relatively little structural and biochemical information is available for this family. Here, we review recent structural and mechanistic work on the 5-phosphatases with a focus on OCRL, whose loss of function results in oculocerebrorenal syndrome of Lowe and Dent 2 disease. Studies of OCRL emphasize how the actions of 5-phosphatases rely on both intrinsic and extrinsic membrane recognition properties for full catalytic function. Additionally, structural analysis of missense mutations in the catalytic domain of OCRL provides insight into the phenotypic heterogeneity observed in Lowe syndrome and Dent disease.

  2. Control of eukaryotic phosphate homeostasis by inositol polyphosphate sensor domains.

    PubMed

    Wild, Rebekka; Gerasimaite, Ruta; Jung, Ji-Yul; Truffault, Vincent; Pavlovic, Igor; Schmidt, Andrea; Saiardi, Adolfo; Jessen, Henning Jacob; Poirier, Yves; Hothorn, Michael; Mayer, Andreas

    2016-05-20

    Phosphorus is a macronutrient taken up by cells as inorganic phosphate (P(i)). How cells sense cellular P(i) levels is poorly characterized. Here, we report that SPX domains--which are found in eukaryotic phosphate transporters, signaling proteins, and inorganic polyphosphate polymerases--provide a basic binding surface for inositol polyphosphate signaling molecules (InsPs), the concentrations of which change in response to P(i) availability. Substitutions of critical binding surface residues impair InsP binding in vitro, inorganic polyphosphate synthesis in yeast, and P(i) transport in Arabidopsis In plants, InsPs trigger the association of SPX proteins with transcription factors to regulate P(i) starvation responses. We propose that InsPs communicate cytosolic P(i) levels to SPX domains and enable them to interact with a multitude of proteins to regulate P(i) uptake, transport, and storage in fungi, plants, and animals.

  3. The interrelationships of the inositol phosphates formed in vasopressin-stimulated WRK-1 rat mammary tumour cells.

    PubMed Central

    Barker, C J; Wong, N S; Maccallum, S M; Hunt, P A; Michell, R H; Kirk, C J

    1992-01-01

    1. Temporal changes in the levels of many inositol phosphates, whose structural characterization is presented in the preceding paper [Wong, Barker, Morris, Craxton, Kirk & Michell (1991) Biochem. J. 286, 459-468], have been monitored in vasopressin-stimulated WRK-1 cells. 2. Upon stimulation, Ins(1,4,5)P3 accumulated within 1 s, consistent with its role as a rapidly acting second messenger produced by receptor activation of phosphoinositidase C. Ins(1,4)P2 and Ins(1,3,4,5)P4, both of which are immediate products of Ins(1,4,5)P3 metabolism, also accumulated quickly. Ins4P, Ins(1,3,4)P3, Ins(3,4)P2, Ins(1,3)P2, Ins1P and Ins3P, which are intermediates in the metabolism of Ins(1,4)P2 and Ins(1,3,4,5)P4 to inositol, accumulated after seconds or within a few minutes, and in a temporal sequence consistent with their known metabolic interrelationships. 3. The stimulated accumulation of Ins(1,3,4,6)P4 was delayed, as expected if it is formed by phosphorylation of Ins(1,3,4)P3. 4. Ins(3,4,5,6)P4 accumulated 2-3-fold in a few minutes, and mainly before Ins(1,3,4,6)P4. 5. Using a [3H]-/[14C]-inositol double-labelling protocol, we obtained evidence that all of the compounds that accumulated upon stimulation, except Ins(3,4,5,6)P4, originated from lipid-derived Ins(1,4,5)P3, but that the newly formed Ins(3,4,5,6)P4 came from a different source. 6. There were no consistent changes in the levels of Ins(1,3,4,5,6)P5 and InsP6 during stimulation. 7. Alongside the gradual accumulation of Ins(1:2-cyclic,4,5)P3 during stimulation [Wong, Barker, Shears, Kirk & Michell (1988) Biochem. J. 252, 1-5], there was an accumulation of Ins(1:2-cyclic,4)P2 and Ins(1:2-cyclic)P, probably as either minor side products of phosphoinositidase C action or metabolites of Ins(1:2-cyclic,4,5)P3. 8. When Li+ was present during stimulation, it redirected the dephosphorylation pathways downstream of Ins(1,4,5)P3 in the manner expected from its inhibition of inositol monophosphatase and Ins(1,4)P2/Ins(1,3,4)P

  4. Arginine Silicate Inositol Complex Accelerates Cutaneous Wound Healing.

    PubMed

    Durmus, Ali Said; Tuzcu, Mehmet; Ozdemir, Oguzhan; Orhan, Cemal; Sahin, Nurhan; Ozercan, Ibrahim Hanifi; Komorowski, James Richard; Ali, Shakir; Sahin, Kazim

    2016-10-14

    Arginine silicate inositol (ASI) complex is a composition of arginine, silicon, and inositol that has been shown to have beneficial effects on vascular health. This study reports the effects of an ASI ointment on wound healing in rats. A full-thickness excision wound was created by using a disposable 5 mm diameter skin punch biopsy tool. In this placebo-controlled study, the treatment group's wound areas were covered by 4 or 10 % ASI ointments twice a day for 5, 10, or 15 days. The rats were sacrificed either 5, 10, or 15 days after the wounds were created, and biopsy samples were taken for biochemical and histopathological analysis. Granulation tissue appeared significantly faster in the ASI-treated groups than in the control groups (P < 0.05). The mean unhealed wound area was significantly smaller, and the mean percentage of total wound healing was significantly higher in ASI-treated wounds than in the control wounds. Hydroxyproline, collagen, and matrix metalloproteinases were measured in the granulated tissue and found to be affected. Inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), collagen, matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), epidermal growth factor (EGF), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), and various cytokines (TNF-α and IL-1β) measured in this study showed a significant fall in expression level in ASI-treated wounds. The results suggest that topical application of ASI ointment (especially 4 % concentration) has beneficial effects on the healing response of an excisional wound.

  5. Do mammals make all their own inositol hexakisphosphate?

    PubMed

    Letcher, Andrew J; Schell, Michael J; Irvine, Robin F

    2008-12-01

    A highly specific and sensitive mass assay for inositol hexakisphosphate (InsP6) was characterized. This centres around phosphorylating InsP6 with [32P]ATP using a recombinant InsP6 kinase from Giardia lambia, followed by HPLC of the 32P-labelled products with an internal [3H]InsP7 standard. This assay was used to quantify InsP6 levels in a variety of biological samples.Concentrations of InsP6 in rat tissues varied from 10-20 microM (assuming 64% of wet weight of tissue is cytosol water), whereas using the same assumption axenic Dictyostelium discoideum cells contained 352 +/- 11 microM InsP6. HeLa cells were seeded at low density and grown to confluence, at which point they contained InsP6 levels per mg of protein similar to rat tissues. This amounted to 1.952 +/- 0.117 nmol InsP6 per culture dish, despite the cells being grown in serum shown to contain no detectable(less than 20 pmol per dish) InsP6. These results demonstrate that mammalian cells synthesize all their own InsP6. Human blood was analysed, and although the white cell fraction contained InsP6 at a concentration comparable with other tissues, in serum and platelet-free plasma no InsP6 was detected (<1 nM InsP6). Human urine was also examined, and also contained no detectable (<5 nM) InsP6. These results suggest that dietary studies purporting to measure InsP6 at micromolar concentrations in human plasma or urine may not have been quantifying this inositol phosphate. Therefore claims that administrating InsP6 in the diet or applying it topically can produce health benefits by increasing extracellular InsP6 levels may require reassessment.

  6. Relationship Between Myo-Inositol Supplementary and Gestational Diabetes Mellitus

    PubMed Central

    Zheng, Xiangqin; Liu, Zhaozhen; Zhang, Yulong; Lin, Yuan; Song, Jianrong; Zheng, Lianghui; Lin, Sheng

    2015-01-01

    Abstract To determine whether myo-inositol supplement will increase the action of endogenous insulin, which is mainly measured by markers of insulin resistance such as homeostasis model assessment of insulin resistance. PubMed, Cochrane Library, Embase, and web of science were comprehensively searched using “gestational diabetes mellitus” and “myo-inositol” to identify relevant studies. Both subject headings and free texts were adopted. The methodological quality of the included studies were assessed and pooled analyzed by the methods recommended by the Cochrane collaboration. A total of 5 trials containing 513 participants were included. There was a significant reduction in aspects of gestational diabetes incidence (risk ratio [RR], 0.29; 95% confidence interval (95% CI), 0.19–0.44), birth weight (mean difference [MD], −116.98; 95% CI, −208.87 to −25.09), fasting glucose oral glucose tolerance test (OGTT) (MD, −0.36; 95% CI, −0.51 to −0.21), 1-h glucose OGTT (MD, −0.63; 95% CI, −1.01 to −0.26), 2-h glucose OGTT (MD, −0.45; 95% CI, −0.75 to −0.16), and related complications (odds ratio [OR], 0.28; 95% CI 0.14–0.58). On the basis of current evidence, myo-inositol supplementation reduces the development of gestational diabetes mellitus (GDM), although this conclusion requires further evaluation in large-scale, multicenter, blinded randomized controlled trials. PMID:26496267

  7. Alterations in Lipid and Inositol Metabolisms in Two Dopaminergic Disorders

    PubMed Central

    Berger, Hannah S.; Do, Kieu Trinh; Kastenmüller, Gabi; Wahl, Simone; Adamski, Jerzy; Peters, Annette; Krumsiek, Jan; Suhre, Karsten; Haslinger, Bernhard; Ceballos-Baumann, Andres; Gieger, Christian; Winkelmann, Juliane

    2016-01-01

    Background Serum metabolite profiling can be used to identify pathways involved in the pathogenesis of and potential biomarkers for a given disease. Both restless legs syndrome (RLS) and Parkinson`s disease (PD) represent movement disorders for which currently no blood-based biomarkers are available and whose pathogenesis has not been uncovered conclusively. We performed unbiased serum metabolite profiling in search of signature metabolic changes for both diseases. Methods 456 metabolites were quantified in serum samples of 1272 general population controls belonging to the KORA cohort, 82 PD cases and 95 RLS cases by liquid-phase chromatography and gas chromatography separation coupled with tandem mass spectrometry. Genetically determined metabotypes were calculated using genome-wide genotyping data for the 1272 general population controls. Results After stringent quality control, we identified decreased levels of long-chain (polyunsaturated) fatty acids of individuals with PD compared to both RLS (PD vs. RLS: p = 0.0001 to 5.80x10-9) and general population controls (PD vs. KORA: p = 6.09x10-5 to 3.45x10-32). In RLS, inositol metabolites were increased specifically (RLS vs. KORA: p = 1.35x10-6 to 3.96x10-7). The impact of dopaminergic drugs was reflected in changes in the phenylalanine/tyrosine/dopamine metabolism observed in both individuals with RLS and PD. Conclusions A first discovery approach using serum metabolite profiling in two dopamine-related movement disorders compared to a large general population sample identified significant alterations in the polyunsaturated fatty acid metabolism in PD and implicated the inositol metabolism in RLS. These results provide a starting point for further studies investigating new perspectives on factors involved in the pathogenesis of the two diseases as well as possible points of therapeutic intervention. PMID:26808974

  8. Lipin-1 regulation of phospholipid synthesis maintains endoplasmic reticulum homeostasis and is critical for triple-negative breast cancer cell survival.

    PubMed

    He, Jingquan; Zhang, Feng; Tay, Li Wei Rachel; Boroda, Salome; Nian, Weiqi; Levental, Kandice R; Levental, Ilya; Harris, Thurl E; Chang, Jeffrey T; Du, Guangwei

    2017-07-01

    Cancer cells reprogram their metabolism to increase the synthesis of macromolecules for rapid proliferation. Compared to fatty acids, much less is known about the synthesis of phospholipids, which is essential for membrane biogenesis in cancer cells. We found that LPIN1, which encodes lipin-1, a phosphatidic acid phosphatase (PAP) controlling the rate-limiting step in the phospholipid synthesis pathway, is highly up-regulated in basal-like triple-negative breast cancer (TNBC). Moreover, high LPIN1 expression correlates with the poor prognosis of these patients. Knockdown of LPIN1 increases apoptosis in basal-like TNBC cell lines, whereas it has minimal or less effect on normal human mammary gland epithelial cells (HMECs) and estrogen receptor-positive breast cancer cell lines. Fatty acid incorporation and lipidomics analyses showed that LPIN1 knockdown blocks phospholipid synthesis and changes membrane lipid compositions that ultimately induce the activation of 1 of the 3 branches of unfolded protein responses, the inositol-requiring enzyme-1α pathway. We also show for the first time, to our knowledge, that lipin-1 knockdown significantly inhibits tumor growth in vivo using an orthotopic xenograft breast mouse model. Our results suggest that lipin-1 is a potential target for cancer therapy.-He, J., Zhang, F., Tay, L. W. R., Boroda, S., Nian, W., Levental, K. R., Levental, I., Harris, T. E., Chang, J. T., Du, G. Lipin-1 regulation of phospholipid synthesis maintains endoplasmic reticulum homeostasis and is critical for triple-negative breast cancer cell survival. © FASEB.

  9. Phospholipid synthesis rates in the eastern subtropical South Pacific Ocean

    NASA Astrophysics Data System (ADS)

    van Mooy, B. A. S.; Moutin, T.; Duhamel, S.; Rimmelin, P.; van Wambeke, F.

    2008-02-01

    Membrane lipid molecules are a major component of planktonic organisms and this is particularly true of the microbial picoplankton that dominate the open ocean; with their high surface-area to volume ratios, the synthesis of membrane lipids places a major demand on their overall cell metabolism. Specifically, the synthesis of cell membrane phospholipids creates a demand for the nutrient phosphorus, and we sought to refine our understanding of the role of phospholipids in the upper ocean phosphorus cycle. We measured the rates of phospholipid synthesis in a transect of the eastern subtropical South Pacific from Easter Island to Concepcion, Chile as part of the BIOSOPE program. Our approach combined standard phosphorus radiotracer incubations and lipid extraction methods. We found that phospholipid synthesis rates varied from less than 1 to greater than 200 pmol P L-1 h-1, and that phospholipid synthesis contributed between less than 5% to greater than 22% of the total PO43- incorporation rate. Changes in the percentage that phospholipid synthesis contributed to total PO43- uptake were strongly correlated with the ratio of primary production to bacterial production, which supported our hypothesis that heterotrophic bacteria were the primary agents of phospholipid synthesis. The spatial variation in phospholipid synthesis rates underscored the importance of heterotrophic bacteria in the phosphorus cycle of the eastern subtropical South Pacific, particularly the hyperoligotrophic South Pacific subtropical gyre.

  10. Aldose Reductase-catalyzed Reduction of Aldehyde Phospholipids

    PubMed Central

    Srivastava, Sanjay; Spite, Matthew; Trent, John O.; West, Matthew B.; Ahmed, Yonis; Bhatnagar, Aruni

    2012-01-01

    SUMMARY Oxidation of unsaturated phospholipids results in the generation of aldehyde side chains that remain esterified to the phospholipid backbone. Such “core” aldehydes elicit immune responses and promote inflammation. However, the biochemical mechanisms by which phospholipid aldehydes are metabolized or detoxified are not well understood. In the studies reported here, we examined whether aldose reductase (AR), which reduces hydrophobic aldehydes, metabolizes phospholipid aldehydes. Incubation with AR led to the reduction of 5-oxovaleroyl, 7-oxo-5-heptenoyl, 5-hydroxy-6-oxo-caproyl, and 5-hydroxy-8-oxo-6-octenoyl phospholipids generated upon oxidation of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC). The enzyme also catalyzed the reduction of phospholipid aldehydes generated from the oxidation of 1-alkyl, and 1-alkenyl analogs of PAPC, and 1-palmitoyl-2-arachidonoyl phosphatidic acid or phosphoglycerol. Aldose reductase catalyzed the reduction of chemically synthesized 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphatidylcholine (POVPC) with a Km of 10 μM. Addition of POVPC to the culture medium led to incorporation and reduction of the aldehyde in COS-7 and THP-1 cells. Reduction of POVPC in these cells was prevented by the AR inhibitors sorbinil and tolrestat and was increased in COS-7 cells overexpressing AR. Together, these observations suggest that AR may be a significant participant in the metabolism of several structurally diverse phospholipid aldehydes. This metabolism may be a critical regulator of the pro-inflammatory and immunogenic effects of oxidized phospholipids. PMID:15465833

  11. Different oxidized phospholipid molecules unequally affect bilayer packing.

    PubMed

    Megli, Francesco M; Russo, Luciana

    2008-01-01

    The aim of this study was to gain more detailed knowledge about the effect of the presence of defined oxidized phospholipid molecules in phospholipid bilayers. After chromatographic and mass spectrometry analysis, the previously used product of the Fenton reaction with unsaturated lecithins proved to consist of a plethora of oxidatively modified lecithins, useless either for the detailed study of the effects brought about in the bilayer or as the source of defined oxidized phospholipid molecules. The latter, particularly 2-(omega-carboxyacyl)- and 2-(n-hydroperoxyacyl)-lecithins, can be more conveniently prepared by chemical or enzymatic synthesis rather than by chemical or physical oxidation. The effect of those molecules and of commercially available 12-hydroxy-stearic and dodecanedioic acid was studied in planar supported phospholipid bilayers (SPBs) by use of EPR spectrometry. The SPBs also contained 2-(5-doxylstearoyl)-lecithin as the spin probe, and the EPR spectral anisotropy loss, indicative of bilayer disordering, was measured as a function of the molar percentage of oxidized lipid. Most oxidized lipid molecules examined in this study were able to induce bilayer disordering, while hydroperoxyl group-bearing acyl chains appeared to be much less effective. It is concluded that the effects of different oxidized phospholipids on phospholipid bilayer structure cannot be generalized, as happens with batch-oxidized phospholipids, and that the use of defined oxidized phospholipid molecular species for membrane oxidative stress guarantees a more reliable and detailed response.

  12. A Microscopic View of Phospholipid Insertion into Biological Membranes

    PubMed Central

    Vermaas, Josh V.; Tajkhorshid, Emad

    2014-01-01

    Understanding the process of membrane insertion is an essential step in developing a detailed mechanism, e.g., for peripheral membrane protein association and membrane fusion. The Highly Mobile Membrane Mimetic (HMMM) has been used to accelerate the membrane association and binding of peripheral membrane proteins in simulations by increasing the lateral diffusion of phospholipid headgroups while retaining an atomistic description of the interface. Through a comparative study, we assess the difference in insertion rate of a free phospholipid into an HMMM as well as into a conventional phospholipid bilayer, and develop a detailed mechanistic model of free phospholipid insertion into biological membranes. The mechanistic insertion model shows that successful, irreversible association of the free phospholipid to the membrane interface, which results in its insertion, is the rate limiting step. Association is followed by independent, sequential insertion of the acyl tails of the free phospholipid into the membrane, with splayed acyl tail intermediates. Use of the HMMM is found to replicate the same intermediate insertion states as in the full phospholipid bilayer, however it accelerates overall insertion by approximately a factor of three, with the probability of successful association of phospholipid to the membrane being significantly enhanced. PMID:24313792

  13. Depletion of acidic phospholipids influences chromosomal replication in Escherichia coli

    PubMed Central

    Fingland, Nicholas; Flåtten, Ingvild; Downey, Christopher D; Fossum-Raunehaug, Solveig; Skarstad, Kirsten; Crooke, Elliott

    2012-01-01

    In Escherichia coli, coordinated activation and deactivation of DnaA allows for proper timing of the initiation of chromosomal synthesis at the origin of replication (oriC) and assures initiation occurs once per cell cycle. In vitro, acidic phospholipids reactivate DnaA, and in vivo depletion of acidic phospholipids, results in growth arrest. Growth can be restored by the expression of a mutant form of DnaA, DnaA(L366K), or by oriC-independent DNA synthesis, suggesting acidic phospholipids are required for DnaA- and oriC-dependent replication. We observe here that when acidic phospholipids were depleted, replication was inhibited with a concomitant reduction of chromosomal content and cell mass prior to growth arrest. This global shutdown of biosynthetic activity was independent of the stringent response. Restoration of acidic phospholipid synthesis resulted in a resumption of DNA replication prior to restored growth, indicating a possible cell-cycle-specific growth arrest had occurred with the earlier loss of acidic phospholipids. Flow cytometry, thymidine uptake, and quantitative polymerase chain reaction data suggest that a deficiency in acidic phospholipids prolonged the time required to replicate the chromosome. We also observed that regardless of the cellular content of acidic phospholipids, expression of mutant DnaA(L366K) altered the DNA content-to-cell mass ratio. PMID:23233230

  14. Phospholipid synthesis rates in the eastern subtropical South Pacific Ocean

    NASA Astrophysics Data System (ADS)

    van Mooy, B. A. S.; Moutin, T.; Duhamel, S.; Rimmelin, P.; van Wambeke, F.

    2007-08-01

    Membrane lipid molecules are a major component of planktonic organisms and this is particularly true of the microbial picoplankton that dominate the open ocean; with their high surface-area to volume ratios, the synthesis of membrane lipids places a major demand on their overall cell metabolism. The synthesis of one class of membrane lipids, the phospholipids, also creates a demand for the nutrient phosphorus, and we sought to refine our understanding of the role of phospholipids in the upper ocean phosphorus cycle. We measured the rates of phospholipid synthesis in a transect of the eastern subtropical South Pacific from Easter Island to Concepcion, Chile as part of the BIOSOPE program. Our approach combined standard phosphorus radiotracer incubations and lipid extraction methods. We found that phospholipid synthesis rates varied from less than 1 to greater than 200 pmol P L-1 h-1, and that phospholipid synthesis contributed between less than 5% to greater than 22% of the total PO43- incorporation rate. Changes in the percentage that phospholipid synthesis contributed to total PO43- incorporation were strongly correlated with the ratio of primary production to bacterial production, which supported our hypothesis that heterotrophic bacteria were the primary agents of phospholipid synthesis. The spatial variation in phospholipid synthesis rates underscored the importance of heterotrophic bacteria in the phosphorus cycle of the eastern subtropical South Pacific, particularly the hyperoligotrophic South Pacific subtropical gyre.

  15. Crystal Structure of the Ligand Binding Suppressor Domain of Type 1 Inositol 1,4,5-Trisphosphate Receptor

    SciTech Connect

    Bosanac, Ivan; Yamazaki, Haruka; Matsu-ura, Toru; Michikawa, Takayuki; Mikoshiba, Katsuhiko; Ikura, Mitsuhiko

    2010-11-10

    Binding of inositol 1,4,5-trisphosphate (IP{sub 3}) to the amino-terminal region of IP{sub 3} receptor promotes Ca{sup 2+} release from the endoplasmic reticulum. Within the amino terminus, the first 220 residues directly preceding the IP{sub 3} binding core domain play a key role in IP{sub 3} binding suppression and regulatory protein interaction. Here we present a crystal structure of the suppressor domain of the mouse type 1 IP{sub 3} receptor at 1.8 {angstrom}. Displaying a shape akin to a hammer, the suppressor region contains a Head subdomain forming the {beta}-trefoil fold and an Arm subdomain possessing a helix-turn-helix structure. The conserved region on the Head subdomain appeared to interact with the IP{sub 3} binding core domain and is in close proximity to the previously proposed binding sites of Homer, RACK1, calmodulin, and CaBP1. The present study sheds light onto the mechanism underlying the receptor's sensitivity to the ligand and its communication with cellular signaling proteins.

  16. Inositol induces a profound alteration in the pattern and rate of synthesis and turnover of membrane lipids in Saccharomyces cerevisiae.

    PubMed

    Gaspar, Maria L; Aregullin, Manuel A; Jesch, Stephen A; Henry, Susan A

    2006-08-11

    The addition of inositol to actively growing yeast cultures causes a rapid increase in the rate of synthesis of phosphatidylinositol and, simultaneously, triggers changes in the expression of hundreds of genes. We now demonstrate that the addition of inositol to yeast cells growing in the presence of choline leads to a dramatic reprogramming of cellular lipid synthesis and turnover. The response to inositol includes a 5-6-fold increase in cellular phosphatidylinositol content within a period of 30 min. The increase in phosphatidylinositol content appears to be dependent upon fatty acid synthesis. Phosphatidylcholine turnover increased rapidly following inositol addition, a response that requires the participation of Nte1p, an endoplasmic reticulum-localized phospholipase B. Mass spectrometry revealed that the acyl species composition of phosphatidylinositol is relatively constant regardless of supplementation with inositol or choline, whereas phosphatidylcholine acyl species composition is influenced by both inositol and choline. In medium containing inositol, but lacking choline, high levels of dimyristoylphosphatidylcholine were detected. Within 60 min following the addition of inositol, dimyristoylphosphatidylcholine levels had decreased from approximately 40% of total phosphatidylcholine to a basal level of less than 5%. nte1Delta cells grown in the absence of inositol and in the presence of choline exhibited lower levels of dimyristoylphosphatidylcholine than wild type cells grown under these same conditions, but these levels remained largely constant after the addition of inositol. These results are discussed in relationship to transcriptional regulation known to be linked to lipid metabolism in yeast.

  17. Effects of formulation and process factors on the crystal structure of freeze-dried Myo-inositol.

    PubMed

    Izutsu, Ken-Ichi; Yomota, Chikako; Okuda, Haruhiro; Kawanishi, Toru; Yamaki, Takuya; Ohdate, Ryohei; Yu, Zhaokun; Yonemochi, Etsuo; Terada, Katsuhide

    2014-08-01

    The objective of this study was to elucidate effects of formulation and process variables on the physical forms of freeze-dried myo-inositol. Physical properties of myo-inositol in frozen solutions, freeze-dried solids, and cooled heat-melt solids were characterized by powder X-ray diffraction (PXRD), thermal analysis (differential scanning calorimetry [DSC] and thermogravimetric), and simultaneous PXRD-DSC analysis. Cooling of heat-melt myo-inositol produced two forms of metastable anhydrate crystals that change to stable form (melting point 225 °C-228 °C) with transition exotherms at around 123 °C and 181 °C, respectively. Freeze-drying of single-solute aqueous myo-inositol solutions after rapid cooling induced crystallization of myo-inositol as metastable anhydrate (transition at 80 °C-125 °C) during secondary drying segment. Contrarily, postfreeze heat treatment (i.e., annealing) induced crystallization of myo-inositol dihydrate. Removal of the crystallization water during the secondary drying produced the stable-form myo-inositol anhydrate crystal. Shelf-ramp slow cooling of myo-inositol solutions resulted in the stable and metastable anhydrous crystal solids depending on the solute concentrations and the solution volumes. Colyophilization with phosphate buffer retained myo-inositol in the amorphous state. Crystallization in different process segments varies crystal form of freeze-dried myo-inositol solids. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  18. Non-Mendelian Inheritance of DNA-Induced Inositol Independence in Neurospora

    PubMed Central

    Mishra, N. C.; Tatum, E. L.

    1973-01-01

    Inositol-independent (inos+) revertants of Neurospora induced in inositol-requiring mutants by treatment with wild-type DNA in previous studies were found to be stable and to grow well in the absence of inositol. Genetic data presented in this paper show that a major proportion of these induced revertants rarely transmitted the inositol independence character (inos+) to their sexual progeny. Non-Mendelian transmission of the transformed character (inos+) was also found to occur in some of the sexual progeny in subsequent generations. These genetic data support the idea that the transforming DNA pieces carrying the genetic information (called exosomes) are not readily integrated into the host genome. It is suggested that elimination of most exosomes during meiosis causes a loss of the genetic information and leads to non-Mendelian transmission of the induced revertant character (inos+). PMID:4521213

  19. Inositol prevents folate-resistant neural tube defects in the mouse.

    PubMed

    Greene, N D; Copp, A J

    1997-01-01

    Clinical trials demonstrate that up to 70% of neural tube defects (NTDs) can be prevented by folic acid supplementation in early pregnancy, whereas the remaining NTDs are resistant to folate. Here, we show that a second vitamin, myo-inositol, is capable of significantly reducing the incidence of spinal NTDs in curly tail mice, a genetic model of folate-resistant NTDs. Inositol increases flux through the inositol/lipid cycle, stimulating protein kinase C activity and upregulating expression of retinoic acid receptor beta, specifically in the caudal portion of the embryonic hindgut. This reduces the delay in closure of the posterior neuropore, the embryonic defect that is known to lead directly to spina bifida in curly tail embryos. Our findings reveal a molecular pathway of NTD prevention and suggest the possible efficacy of combined treatment with folate and inositol in overcoming the majority of human NTDs.

  20. Unlike lithium, anticonvulsants and antidepressants do not alter rat brain myo-inositol.

    PubMed

    McGrath, Brent M; Greenshaw, Andrew J; McKay, Ryan; Slupsky, Carolyn M; Silverstone, Peter H

    2007-10-08

    Lithium is the first-line in bipolar disorder treatment. Lithium's clinical efficacy might be due to its inhibition of myo-inositol turnover in the phosphatidylinositol second messenger system. This study aimed to determine whether this action can extend to antidepressants and anticonvulsants also used to treat bipolar symptoms. Male rats were treated for 2 weeks with an intraperitoneal injection of phenelzine, fluoxetine, desipramine, carbamazepine, lamotrigine, sodium valproate or vehicle. Brains were dissected and myo-inositol concentrations were analyzed using high-field nuclear magnetic resonance spectroscopy at 18.8 T and quantified using Chenomx Profiler software. Brain regions assessed included the prefrontal, temporal and occipital cortical areas as well as the hippocampus. The main finding is that contrary to lithium, the anticonvulsants and antidepressants do not alter brain myo-inositol concentration. This suggests that these agents might work via a mechanism that is not centered on changes in myo-inositol concentration.

  1. Light induces a rapid and transient increase in inositol-trisphosphate in toad rod outer segments

    SciTech Connect

    Brown, J.E.; Blazynski, C.; Cohen, A.I.

    1987-08-14

    The sub-second time course of changes in the content of (/sup 3/H)inositol-1,4,5-trisphosphate was determined in rod outer segments from very rapidly frozen Bufo retinas that had been incubated with (/sup 3/H)inositol. Rod outer segments were cut off frozen specimens with a cryostat microtome and the water soluble extracts were analyzed. The content of (/sup 3/H)inositol-1,4,5-trisphosphate rose after approximately 250 msec of bright illumination, but returned to the unstimulated level after 1 sec, whether the stimulus remained on or not. That is, there was rapid but transient change in the content of (/sup 3/H)inositol-1,4,5-trisphosphate after the onset of stimulation.

  2. Understanding phospholipid function: Why are there so many lipids?

    PubMed

    Dowhan, William

    2017-06-30

    In the 1970s, phospholipids were still considered mere building blocks of the membrane lipid bilayer, but the subsequent realization that phospholipids could also serve as second messengers brought new interest to the field. My own passion for the unique amphipathic properties of lipids led me to seek other, non-signaling functions for phospholipids, particularly in their interactions with membrane proteins. This seemed to be the last frontier in protein chemistry and enzymology to be conquered. I was fortunate to find my way to Eugene Kennedy's laboratory, where both membrane proteins and phospholipids were the foci of study, thus providing a jumping-off point for advancing our fundamental understanding of lipid synthesis, membrane protein biosynthesis, phospholipid and membrane protein trafficking, and the cellular roles of phospholipids. After purifying and characterizing enzymes of phospholipid biosynthesis in Escherichia coli and cloning of several of the genes encoding these enzymes in E. coli and Saccharomyces cerevisiae, I was in a position to alter phospholipid composition in a systematic manner during the cell cycle in these microorganisms. My group was able to establish, contrary to common assumption (derived from the fact that membrane proteins retain activity in detergent extracts) that phospholipid environment is a strong determining factor in the function of membrane proteins. We showed that molecular genetic alterations in membrane lipid composition result in many phenotypes, and uncovered direct lipid-protein interactions that govern dynamic structural and functional properties of membrane proteins. Here I present my personal "reflections" on how our understanding of phospholipid functions has evolved. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Calcium-independent effects of TMB-8. Modification of phospholipid metabolism in neuroblastoma cells by inhibition of choline uptake.

    PubMed Central

    Palmer, F B; Byers, D M; Spence, M W; Cook, H W

    1992-01-01

    TMB-8 [8-(NN-diethylamino)-octyl-3,4,5-trimethoxybenzoate] blocks agonist-stimulated release of Ca2+ from intracellular sites in many cell lines and is often used to distinguish between dependence on extracellular and intracellular Ca2+. In N1E-115 neuroblastoma cells, TMB-8 did not alter the resting cytosolic Ca2+ concentration in unstimulated cells, yet phospholipid metabolism was greatly affected. At concentrations of TMB-8 (25-150 microM) that inhibit Ca2+ release, phosphatidylcholine formation was inhibited, whereas synthesis of phosphatidylinositol, phosphatidylglycerol and phosphatidylserine was stimulated. Unlike other cationic amphipathic compounds, TMB-8 did not inhibit phosphatidate phosphatase or enzymes in the pathway from choline to phosphatidylcholine. Choline transport was the major site of action. TMB-8 was a competitive inhibitor (Ki = 10 microM) of low-affinity (Kt = 20 microM) choline transport. When added at the same time as labelled precursor, TMB-8 also decreased cellular uptake of phosphate and inositol, but not that of ethanolamine or serine. In prelabelled cells, continued uptake and incorporation of phosphate and inositol were not affected. Under these conditions phosphatidylinositol synthesis was increased 2-fold and, like the effect on phosphatidylcholine, reached a plateau at 100 microM-TMB-8. Phosphatidylglycerol synthesis increased linearly with TMB-8 concentration to 40-fold stimulation at 150 microM, suggesting a selective effect on synthesis of phosphatidylglycerol from CDP-diacylglycerol. Phosphatidylserine synthesis was also increased up to 3-fold. These Ca(2+)-independent effects limit the use of TMB-8 in studies of cell signalling that involve stimulated phosphatidylinositol and phosphatidylcholine metabolism. PMID:1530583

  4. Effect of cellular inositol content on ethanol tolerance of Saccharomyces cerevisiae in sake brewing.

    PubMed

    Furukawa, Keiji; Kitano, Hideyuki; Mizoguchi, Haruhiko; Hara, Shodo

    2004-01-01

    The effect of cellular inositol content on the ethanol tolerance of sake yeast was investigated. In a static culture of strain K901 in a synthetic medium, when cells were grown in the presence of inositol in limited amount (L-cells), the inositol content of cells decreased by one-third that of cells grown in the presence of inositol in sufficient amount (H-cells). L-cells exhibited a higher death rate constant than H-cells in the presence of 12-20% ethanol, while no difference in specific ethanol production rate in the presence of 0-18% ethanol between the two cell types was observed. L-cells leaked more intracellular components, such as nucleotides, phosphate and potassium, in the presence of ethanol than H-cells. L-cells exhibited a lower intracellular pH value than H-cells, which represented the lowering of cell vitality by the decrease in H(+) extrusion activity. Furthermore, the plasma membrane H(+)-ATPase activity of L-cells was approximately one-half of that of H-cells. Therefore, it was considered that the decrease in viability in the presence of ethanol due to inositol limitation results from the lowering of H(+)-ATPase activity, which maintains the permeability barrier of the yeast membrane, ensuring the homeostasis of ions in the cytoplasm of yeast cells. It is assumed that the lowering of H(+)-ATPase activity due to inositol limitation is caused by the change in lipid environment of the enzyme, which is affected by inositol-containing glycerophospholipids such as phosphatidylinositol (PI), because in the PI-saturated mixed micellar assay system, the difference in H(+)-ATPase activity between L- and H-cells disappeared. In the early stage of sake mash, inositol limitation lowers the ethanol tolerance due to the decrease in H(+)-ATPase activity as in static culture. In the final stage of sake mash, the disruption of the ino1 gene responsible for inositol synthesis, resulted in a decrease in cell density. Furthermore, the ino1 disruptant, which was not

  5. The RpiR-like repressor IolR regulates inositol catabolism in Sinorhizobium meliloti.

    PubMed

    Kohler, Petra R A; Choong, Ee-Leng; Rossbach, Silvia

    2011-10-01

    Sinorhizobium meliloti, the nitrogen-fixing symbiont of alfalfa, has the ability to catabolize myo-, scyllo-, and D-chiro-inositol. Functional inositol catabolism (iol) genes are required for growth on these inositol isomers, and they play a role during plant-bacterium interactions. The inositol catabolism genes comprise the chromosomally encoded iolA (mmsA) and the iolY(smc01163)RCDEB genes, as well as the idhA gene located on the pSymB plasmid. Reverse transcriptase assays showed that the iolYRCDEB genes are transcribed as one operon. The iol genes were weakly expressed without induction, but their expression was strongly induced by myo-inositol. The putative transcriptional regulator of the iol genes, IolR, belongs to the RpiR-like repressor family. Electrophoretic mobility shift assays demonstrated that IolR recognized a conserved palindromic sequence (5'-GGAA-N6-TTCC-3') in the upstream regions of the idhA, iolY, iolR, and iolC genes. Complementation assays found IolR to be required for the repression of its own gene and for the downregulation of the idhA-encoded myo-inositol dehydrogenase activity in the presence and absence of inositol. Further expression studies indicated that the late pathway intermediate 2-keto-5-deoxy-D-gluconic acid 6-phosphate (KDGP) functions as the true inducer of the iol genes. The iolA (mmsA) gene encoding methylmalonate semialdehyde dehydrogenase was not regulated by IolR. The S. meliloti iolA (mmsA) gene product seems to be involved in more than only the inositol catabolic pathway, since it was also found to be essential for valine catabolism, supporting its more recent annotation as mmsA.

  6. d-chiro-Inositol is absorbed but not synthesized in rodents

    PubMed Central

    Lin, Xiaobo; Ma, Lina; Gopalan, Chaya; Ostlund, Richard E.

    2013-01-01

    d-chiro-Inositol (DCI) and pinitol (1D-3-O-methyl-chiro-inositol) are distinctive inositols reported to possess insulin-mimetic properties. DCI-containing compounds were abundant in common laboratory animal feed. By GC-MS of 6 M-HCl hydrolysates, Purina Laboratory Rodent Diet 5001 (diet 5001) contained 0.23% total DCI by weight with most found in the Lucerne and soy meal components. In contrast, only traces of l-chiro-inositol were observed. The DCI moiety was present in a water-soluble non-ionic form of which most was shown to be pinitol. To measure the absorption of dietary inositols, rats were fed diet 5001 in a balance study or given purified pinitol or [2H6]DCI. More than 98% of the total DCI fed to rats as diet 5001, purified pinitol or [2H6]DCI was absorbed from the gastrointestinal tract. Rats chronically on diet 5001 consumed 921 μmol total DCI/kg body weight pet d but excreted less than 5.3% in the stool and urine, suggesting that the bulk was metabolized. The levels of pinitol or DCI in plasma, stool, or urine remained relatively stable in mice fed Purina PicoLab® Rodent Diet 20 5053 over a 5-week period, whereas these values declined to very low levels in mice fed a pinitol/DCI-deficient chemically-defined diet. To test whether DCI was synthesized or converted from myo-inositol, mice were treated with heavy water or [2H6]myo-inositol. DCI was neither synthesized endogenously from 2H-labelled water nor converted from [2H6]myo-inositol. DCI and pinitol in rodents appear to be derived solely from the diet. PMID:19586572

  7. Inositol metabolism in WRK-1 cells. Relationship of hormone-sensitive to -insensitive pools of phosphoinositides

    SciTech Connect

    Monaco, M.E.

    1987-09-25

    Previous studies have indicated the existence of two separate pools of phosphoinositides in WRK-1 cells; one is labile and hormone-sensitive with respect to turnover, while the other is stable. Hormonal stimulation results in a rapid increase in /sup 32/Pi incorporation into the sensitive pool, while in the absence of hormone, incorporation of /sup 32/Pi into this pool is slow. Results are quite different when (/sup 3/H)inositol is the precursor utilized. Incorporation of (/sup 3/H)inositol into hormone-sensitive phosphoinositides is not stimulated in the presence of hormone, suggesting entry of this exogenous precursor into the cycle by a route other than the resynthetic phase of the cycle. Furthermore, failure of hormone to induce loss of (/sup 3/H)phosphoinositide in pulse-chase experiments in the absence of lithium suggests reutilization of the (/sup 3/H)inositol moiety generated by phosphodiesteratic cleavage of hormone-sensitive phosphoinositide. Time course studies indicate that the relative rates of incorporation of (/sup 3/H)inositol into sensitive and insensitive phosphoinositide remain constant from 2 to 24 h. Several factors are capable of increasing (/sup 3/H)inositol incorporation into hormone-insensitive phosphoinositide including vasopressin, calcium ionophores, and manganese. On the other hand, vasopressin treatment appears to decrease incorporation of (/sup 3/H)inositol into the hormone-sensitive pool, probably by shifting the equilibrium between phosphoinositides and inositol phosphates, since the decrease in radioactivity observed in the phosphoinositides is equaled by the increase observed in that in the inositol phosphates.

  8. Modulation of hemodynamic and vascular filtration changes in diabetic rats by dietary myo-inositol

    SciTech Connect

    Pugliese, G.; Tilton, R.G.; Speedy, A.; Santarelli, E.; Eades, D.M.; Province, M.A.; Kilo, C.; Sherman, W.R.; Williamson, J.R. )

    1990-03-01

    To assess the potential of myo-inositol-supplemented diets to prevent diabetes-induced vascular functional changes, we examined the effects of diets supplemented with 0.5, 1, or 2% myo-inositol on blood flow and vascular filtration function in nondiabetic control rats and rats with streptozocin-induced diabetes (STZ-D). After 1 mo of diabetes and dietary myo-inositol supplementation, (1) 131I-labeled bovine serum albumin (BSA) permeation of vessels was assessed in multiple tissues, (2) glomerular filtration rate (GFR) was estimated as renal plasma clearance of 57Co-labeled EDTA, (3) regional blood flows were measured with 15-microns 85Sr-labeled microspheres, and (4) endogenous albumin and IgG urinary excretion rates were quantified by radial immunodiffusion assay. In STZ-D rats, 131I-BSA tissue clearance increased significantly (2- to 4-fold) in the anterior uvea, choroid-sclera, retina, sciatic nerve, aorta, new granulation tissue, diaphragm, and kidney but was unchanged in skin, forelimb muscle, and heart. myo-Inositol-supplemented diets reduced diabetes-induced increases in 131I-BSA clearance (in a dose-dependent manner) in all tissues; however, only in new granulation tissue and diaphragm did the 2% myo-inositol diet completely normalize vascular albumin permeation. Diabetes-induced increases in GFR and in urinary albumin and IgG excretion were also substantially reduced or normalized by dietary myo-inositol supplements. Increased blood flow in anterior uvea, choroid-sclera, kidney, new granulation tissue, and skeletal muscle in STZ-D rats also was substantially reduced or normalized by the 2% myo-inositol diet. myo-Inositol had minimal if any effects on the above parameters in control rats.

  9. The Yeast Bsd2-1 Mutation Influences Both the Requirement for Phosphatidylinositol Transfer Protein Function and Derepression of Phospholipid Biosynthetic Gene Expression in Yeast

    PubMed Central

    Kagiwada, S.; Kearns, B. G.; McGee, T. P.; Fang, M.; Hosaka, K.; Bankaitis, V. A.

    1996-01-01

    The BSD2-1 allele renders Saccharomyces cerevisiae independent of its normally essential requirement for phosphatidylinositol transfer protein (Sec14p) in the stimulation of Golgi secretory function and cell viability. We now report that BSD2-1 yeast mutants also exhibit yet another phenotype, an inositol auxotrophy. We demonstrate that the basis for this Ino(-) phenotype is the inability of BSD2-1 strains to derepress transcription of INO1, the structural gene for the enzyme that catalyzes the committed step in de novo inositol biosynthesis in yeast. This constitutive repression of INO1 expression is mediated through specific inactivation of Ino2p, a factor required for trans-activation of INO1 transcription, and we show that these transcriptional regulatory defects can be uncoupled from the ``bypass Sec14p'' phenotype of BSD2-1 strains. Finally, we present evidence that newly synthesized phosphatidylinositol is subject to accelerated turnover in BSD2-1 mutants and that prevention of this accelerated phosphatidylinositol turnover in turn negates suppression of Sec14p defects by BSD2-1. We propose that, in BSD2-1 strains, a product(s) generated by phosphatidylinositol turnover coordinately modulates the activities of both the Sec14p/Golgi pathway and the pathway through which transcription of phospholipid biosynthetic genes is derepressed. PMID:8725219

  10. Effects of combined inositol hexakisphosphate and inositol supplement on antioxidant activity and metabolic enzymes in the liver of streptozotocin-induced type 2 diabetic rats.

    PubMed

    Foster, Shadae R; Dilworth, Lowell L; Thompson, Rory K; Alexander-Lindo, Ruby L; Omoruyi, Felix O

    2017-09-25

    Diabetes mellitus is associated with elevated reactive oxygen species, lipid abnormalities, reduced antioxidant activity and organ damage. This study examines the effects of combined inositol hexakisphosphate (IP6) and inositol supplement on antioxidant levels and other biochemical parameters in the liver of type 2 diabetic rats. Five groups of Sprague-Dawley rats were studied. Six rats were fed normal diet (non-diabetic control), while 24 rats were fed high-fat diet (HFD) for 4 weeks. Diabetes was induced in 18 of the rats fed HFD by intraperitoneal administration of streptozotocin. The diabetic rats were separated into three groups namely: combined IP6 and inositol, glibenclamide and diabetic control. The non-diabetic group fed high-fat diet was classified as a high-fat control group. For the final four weeks of the experiment, all rats were fed normal diet and given their respective treatment regimes. Hepatic antioxidant status, metabolic enzyme activity, lipid profile, peroxidative damage and liver histology, as well as, serum aminotransferase and alkaline phosphatase activities, and total bilirubin concentration were assessed. Treatment with combined IP6 and inositol supplement significantly increased liver reduced glutathione and high-density lipoprotein levels while liver triglyceride levels and serum alkaline phosphatase activity were significantly reduced by 27%, 50%, 38.5%, and 69.2% respectively compared to the diabetic control. Hepatic superoxide dismutase, catalase, glucose-6-phosphate dehydrogenase activities were significantly upregulated by 55%, 26% and 53% respectively in the diabetic rats treated with combined IP6 and inositol compared to the diabetic control. Combined IP6 and inositol treatment resulted in the preservation of liver cell integrity and improved antioxidant status in type 2 diabetic rats. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Determination of phytic acid and inositol pentakisphosphates in foods by high-performance ion chromatography.

    PubMed

    Chen, Qingchuan

    2004-07-28

    A high-performance anion exchange chromatographic method was adapted for the quantitative determination of phytic acid and inositol pentakisphosphate isomers (excluding enantiomers) in foods. Because of the cost and limited availability of inositol phosphate standards, a phytic acid sodium salt standard was used for the calculation of an average relative response factor for the quantification of inositol pentakisphosphate isomers, and the purity of phytic acid sodium salt standard was also accurately established. The detection limits (S/N = 3) for phytic acid and inositol pentakisphosphates were in the range of 1.5-3.4 microM (0.1-0.2 microg/100 microL). This method has been successfully applied to the determination of phytic acid and inositol pentakisphosphates in a variety of beans and nuts after extraction with 0.5 M HCl and cleanup with solid phase extraction cartridges. The results demonstrated that there was a strong correlation between either the phytic acid content or the total content of phytic acid together with inositol pentakisphosphates and the total dietary fiber content in the group of all raw dry beans and in the group of raw dry black beans but not in the group of raw dry red kidney beans, which was probably due to the insufficient number of the raw dry red kidney bean samples.

  12. Useful access to enantiomerically pure protected inositols from carbohydrates: the aldohexos-5-uloses route

    PubMed Central

    D’Andrea, Felicia; Catelani, Giorgio; Pistarà, Venerando

    2016-01-01

    The intramolecular aldol condensation of aldohexos-5-ulose derivatives of the D-xylo and L-ribo stereoseries has been studied. Only one of the four possible inososes was isolated from both stereoseries in reasonable yields (30–38%). The results obtained, together with the previous findings for the L-arabino and L-lyxo stereoseries, allowed for the rationalisation of a mechanism of the reaction based on open-transition-state models and electron-withdrawing inductive effects. Complementary reductions of the intermediate inososes were possible by changing the reaction conditions, and two isomeric inositol derivatives were obtained with complete stereoselection from each inosose. The presented approach permits us to control the configuration of three out of the six stereocentres of the inositol frame and gives access to seven of the nine inositols. Noteworthy, for the D-xylo derivative, the two-step sequence (condensation followed by reduction with NaBH(OAc)3) represents the biomimetic synthesis of myo-inositol. Furthermore, the sugar-based pathway leads directly to enantiomerically pure selectively protected inositols and does not require any desymmetrisation procedure which is needed when myo-inositol and other achiral precursors are employed as starting materials. As an example of application of the method, the indirect selective protection of secondary inositols’ hydroxy functions, by placing specific protecting groups on the aldohexos-5-ulose precursor has been presented. PMID:28144301

  13. Regioselective Opening of myo-Inositol Orthoesters: Mechanism and Synthetic Utility

    PubMed Central

    2013-01-01

    Acid hydrolysis of myo-inositol 1,3,5-orthoesters, apart from orthoformates, exclusively affords the corresponding 2-O-acyl myo-inositol products via a 1,2-bridged five-membered ring dioxolanylium ion intermediate observed by NMR spectroscopy. These C-2-substituted inositol derivatives provide valuable precursors for rapid and highly efficient routes to 2-O-acyl inositol 1,3,4,5,6-pentakisphosphates and myo-inositol 1,3,4,5,6-pentakisphosphate with biologically interesting and anticancer properties. Deuterium incorporation into the α-methylene group of such alkyl ester products (2-O-C(O)CD2R), when the analogous alkyl orthoester is treated with deuterated acid, is established utilizing the novel orthoester myo-inositol 1,3,5-orthobutyrate as an example. Such deuterated ester products provide intermediates for deuterium-labeled synthetic analogues. Investigation into this selective formation of 2-O-ester products and the deuterium incorporation is presented with proposed mechanisms from NMR experiments. PMID:23438216

  14. myo-Inositol Oxygenase is Required for Responses to Low Energy Conditions in Arabidopsis thaliana.

    PubMed

    Alford, Shannon R; Rangarajan, Padma; Williams, Phoebe; Gillaspy, Glenda E

    2012-01-01

    myo-Inositol is a precursor for cell wall components, is used as a backbone of myo-inositol trisphosphate (Ins(1,4,5)P(3)) and phosphatidylinositol phosphate signaling molecules, and is debated about whether it is also a precursor in an alternate ascorbic acid synthesis pathway. Plants control inositol homeostasis by regulation of key enzymes involved in myo-inositol synthesis and catabolism. Recent transcriptional profiling data indicate up-regulation of the myo-inositol oxygenase (MIOX) genes under conditions in which energy or nutrients are limited. To test whether the MIOX genes are required for responses to low energy, we first examined MIOX2 and MIOX4 gene expression regulation by energy/nutrient conditions. We found that both MIOX2 and MIOX4 expression are suppressed by exogenous glucose addition in the shoot, but not in the root. Both genes were abundantly expressed during low energy/nutrient conditions. Loss-of-function mutants in MIOX genes contain alterations in myo-inositol levels and growth changes in the root. Miox2 mutants can be complemented with a MIOX2:green fluorescent protein fusion. Further we show here that MIOX2 is a cytoplasmic protein, while MIOX4 is present mostly in the cytoplasm, but also occasionally in the nucleus. Together, these data suggest that MIOX catabolism in the shoot may influence root growth responses during low energy/nutrient conditions.

  15. Plant inositol monophosphatase is a lithium-sensitive enzyme encoded by a multigene family.

    PubMed Central

    Gillaspy, G E; Keddie, J S; Oda, K; Gruissem, W

    1995-01-01

    myo-Inositol monophosphatase (IMP) is a soluble, Li(+)-sensitive protein that catalyzes the removal of a phosphate from myo-inositol phosphate substrates. IMP is required for de novo inositol synthesis from glucose 6-phosphate and for breakdown of inositol trisphosphate, a second messenger generated by the phosphatidylinositol signaling pathway. We cloned the IMP gene from tomato (LeIMP) and show that the plant enzyme is encoded by a small gene family. Three different LeIMP cDNAs encode distinct but highly conserved IMP enzymes that are catalytically active in vitro. Similar to the single IMP from animals, the activities of all three LeIMPs are inhibited by low concentrations of LiCl. LeIMP mRNA levels are developmentally regulated in seedlings and fruit and in response to light. Immunoblot analysis detected three proteins of distinct molecular masses (30, 29, and 28 kD) in tomato; these correspond to the predicted molecular masses of the LeIMPs encoded by the genes. Immunoreactive proteins in the same size range are also present in several other plants. Immunolocalization studies indicated that many cell types within seedlings accumulate LeIMP proteins. In particular, cells associated with the vasculature express high levels of LeIMP protein; this may indicate a coordinate regulation between phloem transport and synthesis of inositol. The presence of three distinct enzymes in tomato most likely reflects the complexity of inositol utilization in higher plants. PMID:8718627

  16. Safety and Pharmacokinetics of Multiple Dose myo-Inositol in Preterm Infants

    PubMed Central

    Phelps, Dale L.; Ward, Robert M.; Williams, Rick L.; Nolen, Tracy L.; Watterberg, Kristi L.; Oh, William; Goedecke, Michael; Ehrenkranz, Richard A.; Fennell, Timothy; Poindexter, Brenda B.; Cotten, C. Michael; Hallman, Mikko; Frantz, Ivan D.; Faix, Roger G.; Zaterka-Baxter, Kristin M.; Das, Abhik; Ball, M. Bethany; Lacy, Conra Backstrom; Walsh, Michele C.; Carlo, Waldemar A.; Sánchez, Pablo J.; Bell, Edward F.; Shankaran, Seetha; Carlton, David P.; Chess, Patricia R.; Higgins, Rosemary D.

    2016-01-01

    BACKGROUND Preterm infants with RDS given inositol had reduced BPD, death and severe ROP. We assessed the safety and pharmacokinetics(PK) of daily inositol to select a dose providing serum levels previously associated with benefit, and to learn if accumulation occurred when administered throughout the normal period of retinal vascularization. METHODS Infants ≤29wks GA (n=122, 14 centers) were randomized and treated with placebo or inositol at 10, 40 or 80mg/kg/day. Intravenous administration converted to enteral when feedings were established, and continued to the first of 10 weeks, 34weeks PMA or discharge. Serum collection employed a sparse sampling population PK design. Inositol urine losses and feeding intakes were measured. Safety was prospectively monitored. RESULTS At 80mg/kg/day mean serum levels reached 140mg/L, similar to Hallman’s findings. Levels declined after 2 weeks, converging in all groups by 6 wks. Analyses showed a mean volume of distribution 0.657 L/kg, clearance 0.058 L/kg/hr, and half-life 7.90 hr. Adverse events and co-morbidities were fewer in the inositol groups, but not significantly so. CONCLUSIONS Multiple dose inositol at 80mg/kg/day was not associated with increased adverse events, achieves previously effective serum levels, and is appropriate for investigation in a Phase 3 trial. PMID:27074126

  17. Purification, crystallization and preliminary crystallographic analysis of mouse myo-inositol oxygenase

    SciTech Connect

    Brown, Peter M. Caradoc-Davies, Tom T.; Dickson, James M.; Cooper, Garth J. S.; Loomes, Kerry M.; Baker, Edward N.

    2006-08-01

    Mouse myo-inositol oxygenase, a key enzyme involved in inositol catabolism, has been expressed, purified and crystallized in a form suitable for structure determination by X-ray crystallography. Myo-inositol oxygenase (MIOX) catalyzes the novel oxidative cleavage of myo-inositol (MI) and its epimer d-chiro inositol (DCI) to d-glucuronate. MIOX utilizes an Fe{sup II}/Fe{sup III} binuclear iron centre for the dioxygen-dependent cleavage of the C1—C6 bond in MI. Despite its key role in inositol metabolism, the structural basis of its unique four-electron oxidation mechanism and its substrate specificity remain unknown. In order to answer these questions and to facilitate the use of this key enzyme for the development of new therapeutic strategies for diabetes, the mouse enzyme has been cloned, expressed in Escherichia coli, purified and crystallized from 4.4 M sodium formate. The crystals belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 44.87, b = 77.26, c = 84.84 Å, and diffract to 2.8 Å resolution.

  18. Stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme of baker's yeast.

    PubMed

    Greiner, R; Alminger, M L; Carlsson, N G

    2001-05-01

    During food processing such as baking, phytate is dephosphorylated to produce degradation products, such as myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphates. Certain myo-inositol phosphates have been proposed to have positive effects on human health. The position of the phosphate groups on the myo-inositol ring is thereby of great significance for their physiological functions. Using a combination of high-performance ion chromatography analysis and kinetic studies the stereospecificity of myo-inositol hexakisphosphate dephosphorylation by a phytate-degrading enzyme from baker's yeast (Saccharomyces cerevisiae) was established. The data demonstrate that the phytate-degrading enzyme from baker's yeast dephosphorylates myo-inositol hexakisphosphate in a stereospecific way by sequential removal of phosphate groups via D-Ins(1,2,4,5,6)P(5), D-Ins(1,2,5,6)P(4), D-Ins(1,2,6)P(3), D-Ins(1,2)P(2), to finally Ins(2)P (notation 3/4/5/6/1). Knowledge of the absolute stereochemical specificity of the baker's yeast phytase allows use of the enzyme to produce defined myo-inositol phosphates for kinetic and physiological studies.

  19. Synthesis of inositol 1,2-(cyclic)-4,5-trisphosphate.

    PubMed Central

    Auchus, R J; Kaiser, S L; Majerus, P W

    1987-01-01

    We have developed a method for synthesis of inositol 1,2-(cyclic)-4,5-trisphosphate from inositol 1,4,5-trisphosphate using a water-soluble carbodiimide. We obtained 1-1.5 mumol of the inositol cyclic trisphosphate starting with 5 mumol of inositol 1,4,5-trisphosphate. The cyclized product was isolated by HPLC on Partisil SAX. The identity of the cyclic product was verified by its hydrolysis to inositol 1,4,5-trisphosphate in acid and by its conversion to 1,2-(cyclic)-4-bisphosphate by a specific 5-phosphomonoesterase from platelets. We also identified the product by 31P NMR spectroscopy, which showed a peak at 17.2 ppm, characteristic of a five-membered cyclic phosphodiester ring, and peaks at 4.1 ppm and 0.8 ppm, indicative of phosphomonoesters. This relatively simple method for producing inositol 1,2-(cyclic)-4,5-trisphosphate will facilitate studies of the physiology of this compound in signal transduction. PMID:3469663

  20. Phospholipid composition modulates carbon nanodiamond-induced alterations in phospholipid domain formation.

    PubMed

    Chakraborty, Aishik; Mucci, Nicolas J; Tan, Ming Li; Steckley, Ashleigh; Zhang, Ti; Forrest, M Laird; Dhar, Prajnaparamita

    2015-05-12

    The focus of this work is to elucidate how phospholipid composition can modulate lipid nanoparticle interactions in phospholipid monolayer systems. We report on alterations in lipid domain formation induced by anionically engineered carbon nanodiamonds (ECNs) as a function of lipid headgroup charge and alkyl chain saturation. Using surface pressure vs area isotherms, monolayer compressibility, and fluorescence microscopy, we found that anionic ECNs induced domain shape alterations in zwitterionic phosphatidylcholine lipids, irrespective of the lipid alkyl chain saturation, even when the surface pressure vs area isotherms did not show any significant changes. Bean-shaped structures characteristic of dipalmitoylphosphatidylcholine (DPPC) were converted to multilobed, fractal, or spiral domains as a result of exposure to ECNs, indicating that ECNs lower the line tension between domains in the case of zwitterionic lipids. For membrane systems containing anionic phospholipids, ECN-induced changes in domain packing were related to the electrostatic interactions between the anionic ECNs and the anionic lipid headgroups, even when zwitterionic lipids are present in excess. By comparing the measured size distributions with our recently developed theory derived by minimizing the free energy associated with the domain energy and mixing entropy, we found that the change in line tension induced by anionic ECNs is dominated by the charge in the condensed lipid domains. Atomic force microscopy images of the transferred anionic films confirm that the location of the anionic ECNs in the lipid monolayers is also modulated by the charge on the condensed lipid domains. Because biological membranes such as lung surfactants contain both saturated and unsaturated phospholipids with different lipid headgroup charges, our results suggest that when studying potential adverse effects of nanoparticles on biological systems the role of lipid compositions cannot be neglected.

  1. Phospholipid monolayers between fluid and solid states.

    PubMed Central

    Helm, C A; Möhwald, H; Kjaer, K; Als-Nielsen, J

    1987-01-01

    Monolayers of the phospholipid dimyristoyl phosphatidic acid on the surface of water have been studied by a combination of the new techniques of synchrotron x-ray diffraction and fluorescence microscopy with classical surface pressure data. The pressure vs. area isotherm changes slope at the surface pressures pi c and pi s. The optical technique demonstrates that between pi c and pi s the fluid phase coexists with a denser "gel" phase. Electron diffraction data have shown that the gel phase has bond orientational order over tens of micrometers. However, the x-ray data demonstrate that positional correlations extend only over tens of angstroms. Thus, the gel phase is not crystalline. Above pi s a solid phase is formed with a positional correlation range that is eight times longer for the chemically purest films. Images FIGURE 1 FIGURE 2 PMID:3651557

  2. Langmuir films containing ibuprofen and phospholipids

    NASA Astrophysics Data System (ADS)

    Geraldo, Vananélia P. N.; Pavinatto, Felippe J.; Nobre, Thatyane M.; Caseli, Luciano; Oliveira, Osvaldo N.

    2013-02-01

    This study shows the incorporation of ibuprofen, an anti-inflammatory drug, in Langmuir monolayers as cell membrane models. Significant effects were observed for dipalmitoyl phosphatidyl choline (DPPC) monolayers with relevant changes in the elasticity of the monolayer. Dipalmitoyl phosphatidyl glycerol (DPPG) monolayers were affected by small concentrations of ibuprofen, from 1 to 5 mol%. For both types of monolayer, ibuprofen could penetrate into the hydrophobic part of the monolayer, which was confirmed with polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). Brewster angle microscopy (BAM) images showed that ibuprofen prevents the formation of large domains of DPPC. The pharmacological action should occur primarily with penetration of ibuprofen via electrically neutral phospholipid headgroups of the membrane.

  3. Cyclic phosphatidic acid - a unique bioactive phospholipid.

    PubMed

    Fujiwara, Yuko

    2008-09-01

    Cyclic phosphatidic acid (CPA) is a naturally occurring analog of the growth factor-like phospholipid mediator, lysophosphatidic acid (LPA). The sn-2 hydroxy group of CPA forms a 5-membered ring with the sn-3 phosphate. CPA affects numerous cellular functions, including anti-mitogenic regulation of the cell cycle, induction of stress fiber formation, inhibition of tumor cell invasion and metastasis, and regulation of differentiation and survival of neuronal cells. Interestingly, many of these cellular responses caused by CPA oppose those of LPA despite the activation of apparently overlapping receptor populations. Since the early 1990s, studies on CPA actions gradually developed, and we are now beginning to understand the importance of this lipid. In this review, we focus on the current knowledge about CPA, including enzymatic formation of CPA, unique biological activities and biological targets of CPA, and we also explore metabolically stabilized CPA analogs.

  4. Phospholipids in mitochondrial dysfunction during hemorrhagic shock.

    PubMed

    Leskova, Galina F

    2016-12-20

    Energy deficiency plays a key role in the development of irreversible shock conditions. Therefore, identifying mitochondrial functional disturbances during hemorrhagic shock should be considered a prospective direction for studying its pathogenesis. Phospholipid (PL)-dependent mechanisms of mitochondrial dysfunction in the brain (i.e., in the frontal lobes of the cerebral hemispheres and medulla oblongata) and liver, which, when damaged, leads to an encephalopathy, are examined in this review. These mechanisms show strong regional specificity. Analyzing the data presented in this review suggests that the basis for mitochondrial functional disturbances is cholinergic hyperactivation, accompanied by a choline deficiency and membrane phosphatidylcholine (PC) depletion. Stabilization of the PL composition in mitochondrial membranes using "empty" PC liposomes could be one of the most important methods for eliminating energy deficiency during massive blood loss.

  5. Lessons from the "Euro-Phospholipid" project.

    PubMed

    Cervera, Ricard

    2008-01-01

    The "Euro-Phospholipid" project started in 1999 with a multicentre, consecutive and prospective design. A total cohort of 1000 patients with antiphospholipid syndrome (APS), derived from 13 countries (Belgium, Bulgaria, Denmark, France, Germany, Greece, Hungary, Israel, Italy, the Netherlands, Portugal, Spain and United Kingdom), has been followed since then by a European consortium that was created as part of the network promoted by the "European Forum on Antiphospholipid Antibodies", a study group devoted to the development of multicentre projects with large populations of APS patients. This project allowed the identification of the prevalence and characteristics of the main clinical and immunological manifestations at the onset and during the evolution of APS and demonstrated that it is possible to recognize more homogeneous subsets of clinical significance.

  6. Perturbing the metabolic dynamics of myo-inositol in developing Brassica napus seeds through in vivo methylation impacts its utilization as phytate precursor and affects downstream metabolic pathways

    PubMed Central

    2013-01-01

    Background myo-Inositol (Ins) metabolism during early stages of seed development plays an important role in determining the distributional relationships of some seed storage components such as the antinutritional factors, sucrose galactosides (also known as raffinose oligosaccharides) and phytic acid (PhA) (myo-inositol 1,2,3,4,5,6-hexakisphosphate). The former is a group of oligosaccharides, which plays a role in desiccation at seed maturation. They are not easily digested by monogastric animals, hence their flatulence-causing properties. Phytic acid is highly negatively charged, which chelates positive ions of essential minerals and decreases their bioavailability. It is also a major cause of phosphate-related water pollution. Our aim was to investigate the influence of competitive diversion of Ins as common substrate on the biosynthesis of phytate and sucrose galactosides. Results We have studied the initial metabolic patterns of Ins in developing seeds of Brassica napus and determined that early stages of seed development are marked by rapid deployment of Ins into a variety of pathways, dominated by interconversion of polar (Ins phosphates) and non-polar (phospholipids) species. In a time course experiment at early stages of seed development, we show Ins to be a highly significant constituent of the endosperm and seed coat, but with no phytate biosynthesis occurring in either tissue. Phytate accumulation appears to be confined mainly within the embryo throughout seed development and maturation. In our approach, the gene for myo-inositol methyltransferase (IMT), isolated from Mesembryanthemum crystallinum (ice plant), was transferred to B. napus under the control of the seed-specific promoters, napin and phaseolin. Introduction of this new metabolic step during seed development prompted Ins conversion to the corresponding monomethyl ether, ononitol, and affected phytate accumulation. We were able to produce homozygous transgenic lines with 19% - 35% average

  7. Hybrid copolymer-phospholipid vesicles: phase separation resembling mixed phospholipid lamellae, but with mechanical stability and control.

    PubMed

    Chen, Dong; Santore, Maria M

    2015-04-07

    Vesicles whose bilayer membranes contain phospholipids mixed with co-polymers or surfactants comprise new hybrid materials having potential applications in drug delivery, sensors, and biomaterials. Here we describe a model polymer-phospholipid hybrid membrane system exhibiting strong similarities to binary phospholipid mixtures, but with more robust membrane mechanics. A lamella-forming graft copolymer, PDMS-co-PEO (polydimethylsiloxane-co-polyethylene oxide) was blended with a high melting temperature phospholipid, DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), over a broad compositional range. The resulting giant hybrid unilamellar vesicles were compared qualitatively and quantitatively to analogous mixed phospholipid membranes in which a low melting temperature phospholipid, DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine), was blended with DPPC. The mechanical properties of the hybrid vesicles, even when phase separated, were robust with high lysis stresses and strains approaching those of the pure copolymer vesicles. The temperature-composition phase diagram of the hybrid vesicles closely resembled that of the mixed phospholipids; with only slightly greater nonidealities in the hybrid compared with DOPC/DPPC mixed membranes. In both systems, it was demonstrated that tension could be used to manipulate DPPC solidification into domains of patchy or striped morphologies that exhibited different tracer incorporation. The patch and stripe-shaped domains are thought to be different solid DPPC polymorphys: ripple and tilt (or gel). This work demonstrates that in mixed-phospholipid bilayers where a high-melting phospholipid solidifies on cooling, the lower-melting phospholipid may be substituted by an appropriate copolymer to improve mechanical properties while retaining the underlying membrane physics.

  8. Anionic phospholipids modulate peptide insertion into membranes.

    PubMed

    Liu, L P; Deber, C M

    1997-05-06

    While the insertion of a hydrophobic peptide or membrane protein segment into the bilayer can be spontaneous and driven mainly by the hydrophobic effect, anionic lipids, which comprise ca. 20% of biological membranes, provide a source of electrostatic attractions for binding of proteins/peptides into membranes. To unravel the interplay of hydrophobicity and electrostatics in the binding of peptides into membranes, we designed peptides de novo which possess the typical sequence Lys-Lys-Ala-Ala-Ala-X-Ala-Ala-Ala-Ala-Ala-X-Ala-Ala-Trp-Ala-Ala-X-Ala-Al a-Ala-Lys-Lys-Lys-Lys-amide, where X residues correspond to "guest" residues which encompass a range of hydrophobicity (Leu, Ile, Gly, and Ser). Circular dichroism spectra demonstrated that peptides were partially (40-90%) random in aqueous buffer but were promoted to form 100% alpha-helical structures by anionic lipid micelles. In neutral lipid micelles, only the relatively hydrophobic peptides (X = L and I) spontaneously adopted the alpha-helical conformation, but when 25% of negatively charged lipids were mixed in to mimic the content of anionic lipids in biomembranes, the less hydrophobic (X = S and G) peptides then formed alpha-helical conformations. Consistent with these findings, fluorescence quenching by the aqueous-phase quencher iodide indicated that in anionic (dimyristoylphosphatidylglycerol) vesicles, the peptide Trp residue was buried in the lipid vesicle hydrophobic core, while in neutral (dimyristoylphosphatidylcholine) vesicles, only hydrophobic (X = L and I) peptides were shielded from the aqueous solution. Trp emission spectra of peptides in the presence of phospholipids doxyl-labeled at the 5-, 7-, 10-, 12-, and 16-fatty acid positions implied not only a transbilayer orientation for inserted peptides but also that mixed peptide populations (transbilayer + surface-associated) may arise. Overall results suggest that for hydrophobic peptides with segmental threshold hydrophobicity below that which

  9. Influence of pH and phospholipid species on release of acetaminophen from tablets containing phospholipids.

    PubMed

    Fujii, M; Moriyama, J; Hamazumi, N; Matsumoto, M

    1998-02-01

    The release of acetaminophen (AAP) from tablets containing phospholipids was examined using hydrogenated soybean phospholipid (HSL) and its main components, phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI), although the PI was not well purified (PI rich). Tablets compressed with 400 kgf had about 9% porosity and 2-4 kgf hardness. The release patterns of AAP from the tablets were fitted to Higuchi's square root of time law. The release rate was influenced by the pH of the medium, though solubility of AAP did not change with pH. PC tablets showed faster release at pH of less than 3 than that at pH of above 3, whereas PI rich and HSL tablets showed faster release at pH of above 3 than that at pH of less than 3. The release rate from PE tablets was little affected by pH. A linear relationship exists between the release rate of AAP and the rate of water absorption by the tablet. The ionization state of the phospholipids changes with the pH of the medium, and affects the hydration characteristics. The fully ionized state, at pH of less than 3 in the case of PC and above 3 in the case of PI is most effective on hydration. PE does not fully ionize because of intermolecular hydrogen bonding.

  10. Phospholipid monolayers probed by vibrational sum frequency spectroscopy: instability of unsaturated phospholipids.

    PubMed

    Liljeblad, Jonathan F D; Bulone, Vincent; Tyrode, Eric; Rutland, Mark W; Johnson, C Magnus

    2010-05-19

    The surface specific technique vibrational sum frequency spectroscopy has been applied to in situ studies of the degradation of Langmuir monolayers of 1,2-diacyl-phosphocholines with various degrees of unsaturation in the aliphatic chains. To monitor the degradation of the phospholipids, the time-dependent change of the monolayer area at constant surface pressure and the sum frequency intensity of the vinyl CH stretch at the carbon-carbon double bonds were measured. The data show a rapid degradation of monolayers of phospholipids carrying unsaturated aliphatic chains compared to the stable lipids carrying fully saturated chains when exposed to the ambient laboratory air. In addition, the degradation of the phospholipids can be inhibited by purging the ambient air with nitrogen. This instability may be attributed to spontaneous degradation by oxidation mediated by various reactive species in the air. To further elucidate the process of lipid oxidation in biological membranes artificial Langmuir monolayers probed by a surface specific spectroscopic technique as in this study can serve as a model system for studying the degradation/oxidation of cell membrane constituents.

  11. Marine by-product phospholipids as booster of medicinal compounds.

    PubMed

    Takahashi, Koretaro; Inoue, Yoshikazu

    2012-01-01

    Marine phospholipids are defined as phospholipids containing docosahexaenoic acid (DHA) or eicosapentaenoic acid that would be more effective than fish oil, which is mostly composed of triacylglycerol, in exerting health benefits. Marine phospholipids would boost the effect of both the health-beneficial hydrophilic and the hydrophobic compounds such as cell differentiators, anticancer compounds, and antiobesity compounds. When marine phospholipids are served as liposomal drinks, they would be more effective than adding into solid foods or feeds. As long as the liposome bilayer is basically composed of marine phospholipids, they would promote the encapsulated functional compounds. And this is the principal advantage of choosing marine phospholipids as liposomal membrane. Bioconversion of marine phospholipid would also be advantageous in delivering DHA into the desired tissue. For example, lysophosphatidylserine obtained through phospholipase D-mediated transphosphatidylation and phospholipase A₁ or sn-1 positional specific lipase-mediated partial hydrolysis seemed to be the most effective chemical form in delivering DHA into brain. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Abscisic acid-lipid interactions: a phospholipid monolayer study.

    PubMed

    Bürner, H; Benz, R; Gimmler, H; Hartung, W; Stillwell, W

    1993-08-15

    Lipid monolayer studies were performed on a Langmuir trough in the absence and in the presence of the plant hormone abscisic acid (ABA). The ABA-induced effects on the lipid monolayers can be summarized as follows: (i) ABA as the free acid (pH below 5.3) increased the molecular area and slightly decreased the surface pressure in the collapse points of monolayers made of saturated, unsaturated and of mixed lipids; ABA as the anion showed only minor effects. (ii) The ABA-induced area increase of the lipid monolayers decreased when the surface pressure increased, but some ABA remained in the monolayers made of unsaturated phospholipids even at collapse pressure. (iii) The incorporation of ABA into the monolayers could be inhibited by adding the plant sterol beta-sitosterol to the monolayer forming phospholipids. (iv) There was no substantial difference of ABA action on plant phospholipids as compared with other phospholipids. (v) ABA had a much stronger influence on unsaturated phospholipids than on saturated ones. (vi) ABA decreased the phase-transition temperature of saturated phospholipids. These results, which agree with those obtained from phospholipid vesicle studies, indicate that the physical state of the lipid is important for the ability of ABA penetrating into the lipid monolayer. Finally, a possible relevance of these results is discussed in terms of the action of ABA on guard cell membranes of plants.

  13. Determining the effects of inositol supplementation and the opi1 mutation on ethanol tolerance of Saccharomyces cerevisiae.

    PubMed

    Krause, Erin L; Villa-García, Manuel J; Henry, Susan A; Walker, Larry P

    2007-11-07

    The yeast Saccharomyces cerevisiae is an important microorganism for the ethanol fuel industry. As with many microorganisms, the production and accumulation of certain metabolites, such as ethanol, can have a detrimental effect on cell growth and productivity. Yeast cells containing a higher concentration of phosphatidylinositol (PI) in the cellular membrane, due to inositol supplementation in the growth media, have been shown to tolerate and produce higher concentrations of ethanol. The specific goal of our research was to assess the effects of inositol supplementation in the growth media as well as to compare the ethanol tolerance of the wild-type S. cerevisiae to a mutant, the opi1 strain (opi=overproduction of inositol). The OPI1 gene product is a negative regulatory factor that controls the transcription of the INO1 structural gene, which encodes the enzyme catalyzing the limiting step in the biosynthesis of inositol, that is, the conversion of glucose-6-phosphate to inositol-3-phosphate. Upon the deletion of the OPI1 gene, the cell will constitutively produce inositol, regardless of the extracellular inositol concentration. Inositol supplementation in cultures of wild-type cells increased ethanol tolerance in terms of cell viability. Cells grown in -I media had a 20% higher specific death rate than cells grown in +I media when exposed to 15% ethanol. The opi1 strain, with the ability to constitutively produce inositol regardless of media composition, showed less inhibition of cell growth in the presence of ethanol than did the wild-type strain, particularly in inositol-free media. We conclude that the introduction of an opi1 mutation in yeast results in an inherent increase in PI levels and constitutive biosynthesis of inositol that, in turn, will reduce the cost of supplementing inositol into the media to achieve a higher ethanol tolerance.

  14. Crystal Structure and Product Analysis of an Archaeal myo-Inositol Kinase Reveal Substrate Recognition Mode and 3-OH Phosphorylation.

    PubMed

    Nagata, Ryuhei; Fujihashi, Masahiro; Sato, Takaaki; Atomi, Haruyuki; Miki, Kunio

    2015-06-09

    The TK2285 protein from Thermococcus kodakarensis was recently characterized as an enzyme catalyzing the phosphorylation of myo-inositol. Only two myo-inositol kinases have been identified so far, the TK2285 protein and Lpa3 from Zea mays, both of which belong to the ribokinase family. In either case, which of the six hydroxyl groups of myo-inositol is phosphorylated is still unknown. In addition, little is known about the myo-inositol binding mechanism of these enzymes. In this work, we determined two crystal structures: those of the TK2285 protein complexed with the substrates (ATP analogue and myo-inositol) or the reaction products formed by the enzyme. Analysis of the ternary substrates-complex structure and site-directed mutagenesis showed that five residues were involved in the interaction with myo-inositol. Structural comparison with other ribokinase family enzymes indicated that two of the five residues, Q136 and R140, are characteristic of myo-inositol kinase. The crystal structure of the ternary products-complex, which was prepared by incubating the TK2285 protein with myo-inositol and ATP, holds 1d-myo-inositol 3-phosphate (Ins(3)P) in the active site. NMR and HPLC analyses with a chiral column also indicated that the TK2285 reaction product was Ins(3)P. The results obtained here showed that the TK2285 protein specifically catalyzes the phosphorylation of the 3-OH of myo-inositol. We thus designated TK2285 as myo-inositol 3-kinase (MI3K). The precise identification of the reaction product should provide a sound basis to further explore inositol metabolism in Archaea.

  15. Phospholipids at the Interface: Current Trends and Challenges

    PubMed Central

    Pichot, Roman; Watson, Richard L.; Norton, Ian T.

    2013-01-01

    Phospholipids are one of the major structural elements of biological membranes. Due to their amphiphilic character, they can adopt various molecular assemblies when dispersed in water, such as bilayer vesicles or micelles, which give them unique interfacial properties and render them very attractive in terms of foam or emulsion stabilization. This article aims at reviewing the properties of phospholipids at the air/water and oil/water interfaces, as well as the recent advances in using these natural components as stabilizers, alone or in combination with other compounds such as proteins. A discussion regarding the challenges and opportunities offered by phospholipids-stabilized structure concludes the review. PMID:23736688

  16. Making heads or tails of phospholipids in mitochondria

    PubMed Central

    Osman, Christof; Voelker, Dennis R.

    2011-01-01

    Mitochondria are dynamic organelles whose functional integrity requires a coordinated supply of proteins and phospholipids. Defined functions of specific phospholipids, like the mitochondrial signature lipid cardiolipin, are emerging in diverse processes, ranging from protein biogenesis and energy production to membrane fusion and apoptosis. The accumulation of phospholipids within mitochondria depends on interorganellar lipid transport between the endoplasmic reticulum (ER) and mitochondria as well as intramitochondrial lipid trafficking. The discovery of proteins that regulate mitochondrial membrane lipid composition and of a multiprotein complex tethering ER to mitochondrial membranes has unveiled novel mechanisms of mitochondrial membrane biogenesis. PMID:21220505

  17. Copper(II) and iron(III) ions inhibit respiration and increase free radical-mediated phospholipid peroxidation in rat liver mitochondria: Effect of antioxidants.

    PubMed

    Saporito-Magriñá, Christian; Musacco-Sebio, Rosario; Acosta, Juan M; Bajicoff, Sofía; Paredes-Fleitas, Paola; Reynoso, Sofia; Boveris, Alberto; Repetto, Marisa G

    2017-07-01

    Rat liver mitochondria (1.5-2.1mg protein·mL(-1)) supplemented with either 25 and 100μM Cu(2+) or 100 and 500μM Fe(3+) show inhibition of active respiration (O2 consumption in state 3) and increased phospholipid peroxidation . Liver mitochondria were supplemented with the antioxidants reduced glutathione, N-acetylcysteine or butylated hydroxitoluene, to evaluate their effects on the above-mentioned alterations. Although the mitochondrial dysfunction is clearly associated to phospholipid peroxidation, the different responses to antioxidant supplementation indicate that the metal ions have differences in their mechanisms of toxicity. Mitochondrial phospholipid peroxidation through the formation of hydroxyl radical by a Fenton/Haber-Weiss mechanism seems to precede the respiratory inhibition and to be the main fact in Fe-induced mitochondrial dysfunction. In the case of Cu(2+), it seems that the ion oxidizes glutathione, and low molecular weight protein thiol groups in a direct reaction, as part of its intracellular redox cycling. The processes involving phospholipid peroxidation, protein oxidation and mitochondrial respiratory inhibition characterize a redox dyshomeostatic situation that ultimately leads to cell death. However, Cu(2+) exposure involves an additional, yet unidentified, toxic event as previous reduction of the metal with N-acetylcysteine has only a minor effect in preventing the mitochondrial damage. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Comprehensive analysis of phospholipids in the brain, heart, kidney, and liver: brain phospholipids are least enriched with polyunsaturated fatty acids.

    PubMed

    Choi, Jaewoo; Yin, Tai; Shinozaki, Koichiro; Lampe, Joshua W; Stevens, Jan F; Becker, Lance B; Kim, Junhwan

    2017-10-09

    It is commonly accepted that brain phospholipids are highly enriched with long-chain polyunsaturated fatty acids (PUFAs). However, the evidence for this remains unclear. We used HPLC-MS to analyze the content and composition of phospholipids in rat brain and compared it to the heart, kidney, and liver. Phospholipids typically contain one PUFA, such as 18:2, 20:4, or 22:6, and one saturated fatty acid, such as 16:0 or 18:0. However, we found that brain phospholipids containing monounsaturated fatty acids in the place of PUFAs are highly elevated compared to phospholipids in the heart, kidney, and liver. The relative content of phospholipid containing PUFAs is ~ 60% in the brain, whereas it is over 90% in other tissues. The most abundant species of phosphatidylcholine (PC) is PC(16:0/18:1) in the brain, whereas PC(18:0/20:4) and PC(16:0/20:4) are predominated in other tissues. Moreover, several major species of plasmanyl and plasmenyl phosphatidylethanolamine are found to contain monounsaturated fatty acid in the brain only. Overall, our data clearly show that brain phospholipids are the least enriched with PUFAs of the four major organs, challenging the common belief that the brain is highly enriched with PUFAs.

  19. Myo-inositol soft gel capsules may prevent the risk of coffee-induced neural tube defects.

    PubMed

    De Grazia, Sara; Carlomagno, Gianfranco; Unfer, Vittorio; Cavalli, Pietro

    2012-09-01

    Neural tube defects (NTDs) are classified as folate sensitive (about 70%) and folate resistant (about 30%); although folic acid is able to prevent the former, several data have shown that inositol may prevent the latter. It has recently been proposed that coffee intake might represent a risk factor for NTD, likely by interfering with the inositol signaling. In the present study, we tested the hypothesis that, beside affecting the inositol signaling pathway, coffee also interferes with inositol absorption. In order to evaluate coffee possible negative effects on inositol gastrointestinal absorption, a single-dose bioavailability trial was conducted. Pharmacokinetics (PK) parameters of myo-inositol (MI) powder and MI soft gelatin capsules swallowed with water and with a single 'espresso' were compared. PK profiles were obtained by analysis of MI plasma concentration, and the respective MI bioavailability was compared. Myo-inositol powder administration was negatively affected by coffee intake, thus suggesting an additional explanation to the interference between inositol deficiency and coffee consumption. On the contrary, the concomitant single 'espresso' consumption did not affect MI absorption following MI soft gelatin capsules administration. Furthermore, it was observed that MI soft gelatin capsule administration resulted in improved bioavailability compared to the MI powder form. Myo-inositol soft gelatin capsules should be considered for the preventive treatment of NTDs in folate-resistant subjects due to their higher bioavailability and to the capability to reduce espresso interference.

  20. Early effects of Escherichia coli endotoxin infusion on vasopressin-stimulated breakdown and metabolism of inositol lipids in rat hepatocytes

    SciTech Connect

    Rodriguez de Turco, E.B.; Spitzer, J.A.

    1988-08-30

    The turnover of vasopressin-stimulated 32P-phosphoinositides and 32P-phosphatidic acid and accumulation of (2-3H)-inositol phosphates were examined in hepatocytes from rats infused i.v. with saline and E. coli endotoxin for 3 hrs. Within 60s of VP stimulation the decrease in phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate labeling as well as the increased uptake of 32P into phosphatidic acid were similar in both groups. However, at a later time (300s) the 32P-phosphatidylinositol turnover was greatly decreased concomitantly with a higher labeling of phosphatidic acid. The accumulation of (2-3H)-inositol phosphates in ET-cells was significantly decreased both at 30s and 600s after VP addition. The distribution of (2-3H)-inositol labeling accumulated in the different inositol phosphate fractions over the first 30s of VP stimulation showed a tendency to lower accumulation of inositol trisphosphate, and a significantly lower accumulation of inositol bisphosphate simultaneously with a higher labeling of the inositol tetrakisphosphate fraction. These observations reflect an early effect of ET-infusion on VP-stimulated inositol lipid turnover and on the subsequent metabolism of the released inositol phosphates.

  1. Identification of a secretory phospholipase A2 from Papaver somniferum L. that transforms membrane phospholipids.

    PubMed

    Jablonická, Veronika; Mansfeld, Johanna; Heilmann, Ingo; Obložinský, Marek; Heilmann, Mareike

    2016-09-01

    The full-length sequence of a new secretory phospholipase A2 was identified in opium poppy seedlings (Papaver somniferum L.). The cDNA of poppy phospholipase A2, denoted as pspla2, encodes a protein of 159 amino acids with a 31 amino acid long signal peptide at the N-terminus. PsPLA2 contains a PLA2 signature domain (PA2c), including the Ca(2+)-binding loop (YGKYCGxxxxGC) and the catalytic site motif (DACCxxHDxC) with the conserved catalytic histidine and the calcium-coordinating aspartate residues. The aspartate of the His/Asp dyad playing an important role in animal sPLA2 catalysis is substituted by a serine residue. Furthermore, the PsPLA2 sequence contains 12 conserved cysteine residues to form 6 structural disulfide bonds. The calculated molecular weight of the mature PsPLA2 is 14.0 kDa. Based on the primary structure PsPLA2 belongs to the XIB group of PLA2s. Untagged recombinant PsPLA2 obtained by expression in Escherichia coli, renaturation from inclusion bodies and purification by cation-exchange chromatography was characterized in vitro. The pH optimum for activity of PsPLA2 was found to be pH 7, when using mixed micelles of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and Triton X-100. PsPLA2 specifically cleaves fatty acids from the sn-2 position of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and shows a pronounced preference for PC over phosphatidyl ethanolamine, -glycerol and -inositol. The active recombinant enzyme was tested in vitro against natural phospholipids isolated from poppy plants and preferably released the unsaturated fatty acids, linoleic acid and linolenic acid, from the naturally occurring mixture of substrate lipids.

  2. The inositol trisphosphate receptor in the control of autophagy.

    PubMed

    Criollo, Alfredo; Vicencio, José Miguel; Tasdemir, Ezgi; Maiuri, M Chiara; Lavandero, Sergio; Kroemer, Guido

    2007-01-01

    The second messenger myo-inositol-1,4,5-trisphosphate (IP(3)) acts on the IP(3) receptor (IP(3)R), an IP(3)-activated Ca(2+) channel of the endoplasmic reticulum (ER). The IP(3)R agonist IP(3) inhibits starvation-induced autophagy. The IP(3)R antagonist xestospongin B induces autophagy in human cells through a pathway that requires the obligate contribution of Beclin-1, Atg5, Atg10, Atg12 and hVps34, yet is inhibited by ER-targeted Bcl-2 or Bcl-XL, two proteins that physically interact with IP(3)R. Autophagy can also be induced by depletion of the IP(3)R by small interfering RNAs. Autophagy induction by IP(3)R blockade cannot be explained by changes in steady state levels of Ca(2+) in the endoplasmic reticulum (ER) and the cytosol. Autophagy induction by IP(3)R blockade is effective in cells lacking the obligate mediator of ER stress IRE1. In contrast, IRE1 is required for autophagy induced by ER stress-inducing agents such a tunicamycin or thapsigargin. These findings suggest that there are several distinct pathways through which autophagy can be initiated at the level of the ER.

  3. Regulation of autophagy by the inositol trisphosphate receptor.

    PubMed

    Criollo, A; Maiuri, M C; Tasdemir, E; Vitale, I; Fiebig, A A; Andrews, D; Molgó, J; Díaz, J; Lavandero, S; Harper, F; Pierron, G; di Stefano, D; Rizzuto, R; Szabadkai, G; Kroemer, G

    2007-05-01

    The reduction of intracellular 1,4,5-inositol trisphosphate (IP(3)) levels stimulates autophagy, whereas the enhancement of IP(3) levels inhibits autophagy induced by nutrient depletion. Here, we show that knockdown of the IP(3) receptor (IP(3)R) with small interfering RNAs and pharmacological IP(3)R blockade is a strong stimulus for the induction of autophagy. The IP(3)R is known to reside in the membranes of the endoplasmic reticulum (ER) as well as within ER-mitochondrial contact sites, and IP(3)R blockade triggered the autophagy of both ER and mitochondria, as exactly observed in starvation-induced autophagy. ER stressors such as tunicamycin and thapsigargin also induced autophagy of ER and, to less extent, of mitochondria. Autophagy triggered by starvation or IP(3)R blockade was inhibited by Bcl-2 and Bcl-X(L) specifically targeted to ER but not Bcl-2 or Bcl-X(L) proteins targeted to mitochondria. In contrast, ER stress-induced autophagy was not inhibited by Bcl-2 and Bcl-X(L). Autophagy promoted by IP(3)R inhibition could not be attributed to a modulation of steady-state Ca(2+) levels in the ER or in the cytosol, yet involved the obligate contribution of Beclin-1, autophagy-related gene (Atg)5, Atg10, Atg12 and hVps34. Altogether, these results strongly suggest that IP(3)R exerts a major role in the physiological control of autophagy.

  4. Cellular Cations Control Conformational Switching of Inositol Pyrophosphate Analogues.

    PubMed

    Hager, Anastasia; Wu, Mingxuan; Wang, Huanchen; Brown, Nathaniel W; Shears, Stephen B; Veiga, Nicolás; Fiedler, Dorothea

    2016-08-22

    The inositol pyrophosphate messengers (PP-InsPs) are emerging as an important class of cellular regulators. These molecules have been linked to numerous biological processes, including insulin secretion and cancer cell migration, but how they trigger such a wide range of cellular responses has remained unanswered in many cases. Here, we show that the PP-InsPs exhibit complex speciation behaviour and propose that a unique conformational switching mechanism could contribute to their multifunctional effects. We synthesised non-hydrolysable bisphosphonate analogues and crystallised the analogues in complex with mammalian PPIP5K2 kinase. Subsequently, the bisphosphonate analogues were used to investigate the protonation sequence, metal-coordination properties, and conformation in solution. Remarkably, the presence of potassium and magnesium ions enabled the analogues to adopt two different conformations near physiological pH. Understanding how the intrinsic chemical properties of the PP-InsPs can contribute to their complex signalling outputs will be essential to elucidate their regulatory functions.

  5. Inositol hexaphosphate (IP6): a novel treatment for pancreatic cancer.

    PubMed

    Somasundar, Ponnandai; Riggs, Dale R; Jackson, Barbara J; Cunningham, Cynthia; Vona-Davis, Linda; McFadden, David W

    2005-06-15

    Inositol hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate found in food sources high in fiber content. IP6 has been reported to have significant inhibitory effects against a variety of primary tumors including breast and colon. The effects of IP6 have not been evaluated in pancreatic cancer. We hypothesized that IP6 would significantly inhibit cell growth and increase the apoptotic rate of pancreatic cancer in vitro. Two pancreatic cancer cell lines (MIAPACA and PANC1) were cultured using standard techniques and treated with IP6 at doses of 0.5, 1.0, and 5.0 mm. Cell viability was measured by MTT at 24 and 72 h. Apoptosis was evaluated by Annexin V-FITC and results calculated using FACS analysis. Statistical analysis was performed by ANOVA. Significant reductions (P < 0.01) in cellular proliferation were observed with all IP6 concentrations tested in both cell lines and at both time points. Reductions in cell proliferation ranged from 37.1 to 91.5%. IP6 increased early and late apoptotic activity (P < 0.01). Treatment of pancreatic cancer with the common dietary polyphosphorylated carbohydrate IP6 significantly decreased cellular growth and increased apoptosis. Our findings suggest that IP6 has the potential to become an effective adjunct for pancreatic cancer treatment. Further in vivo and human studies are needed to evaluate safety and clinical utility of this agent in patients with pancreatic cancer.

  6. The effect of inositol hexaphosphate on cadmium sorption to gibbsite.

    PubMed

    Ruyter-Hooley, Maika; Larsson, Anna-Carin; Johnson, Bruce B; Antzutkin, Oleg N; Angove, Michael J

    2016-07-15

    Oxides, hydrous oxides and hydroxides of aluminium and iron are important in determining the availability of trace and heavy metals in soil systems. The presence of complexing anions is also known to affect the binding of these metals in soils. Since organophosphates, such as inositol hexaphosphate (IP6), are present in most soil systems they are expected to affect the nature of the interaction between metal ions and metal (hyr)oxides. Both adsorption edge and isotherm experiments were conducted on Cd(II)-gibbsite and Cd(II)-IP6-gibbsite systems. In addition, solid-state (31)P MAS NMR measurements were performed on the ternary system. All results were used to develop Extended Constant Capacitance surface complexation models of both the Cd(II)-gibbsite and IP6-Cd(II)-gibbsite sorption systems. The presence of IP6 significantly increased sorption of Cd(II) to gibbsite below pH 8 especially at higher concentrations of Cd(II) and IP6. The (31)P MAS NMR spectra, together with surface complexation modeling, indicated the presence of two outer-sphere ternary complexes with the first, [(SOH2)3(3+)(LHCd)(9-)](6-), important at relatively low concentrations, while the second, [SLH3(8-)Cd(2+)](6-), dominated sorption at higher sorbate concentrations. Thus the presence of organophosphates in soil systems increases sorption and may therefore decrease the availability of trace and heavy metals to plants. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Enigmatic ion-exchange behavior of myo-inositol phosphates.

    PubMed

    Shelor, C Phillip; Liao, Hongzhu; Kadjo, Akinde Florence; Dasgupta, Purnendu K

    2015-05-05

    The separation of myo-inositol mono-, di-, tri-, tetra-, pentakis-, and hexakisphosphate (InsP1, InsP2, InsP3, InsP4, InsP5, InsP6) was carried out using hydroxide eluent ion chromatography. Acid hydrolysis of InsP6 (phytate) was used to prepare a distribution of InsPs, ranging from InsP1 to InsP5's and including unhydrolyzed InsP6. Counting all possible positional isomers (many of which have stereoisomers that will not be separable by conventional ion exchange), 40 chromatographically separable peaks are possible; up to 22 were separated and identified by mass spectrometry. InsPs show unusual ion-exchange behavior in two respects: (a) the retention order is not monotonically related with the charge on the ion and (b) at the same hydroxide eluent concentration, retention is greatly dependent on the eluent metal cation. The retention of InsP3-InsP6 was determined to be controlled by steric factors while elution was influenced by eluent cation complexation. These highly phosphorylated InsPs have a much greater affinity for alkali metals (Li(+) > Na(+) > K(+)) than quaternary ammonium ions. This difference in cation affinity was exploited to improve separation through the use of a tetramethylammonium hydroxide-sodium hydroxide gradient.

  8. Hysteresis in myo-inositol utilization by Salmonella Typhimurium.

    PubMed

    Hellinckx, Jessica; Fuchs, Thilo M

    2016-12-27

    Growth of Salmonella enterica serovar Typhimurium strain 14028 with myo-inositol (MI) as the sole carbon and energy source is characterized by a bistable phenotype that manifests in a growth phenotype with an extraordinarily long and length-variable lag phase. However, in the presence of hydrogen carbonate, in the absence of IolR that represses the MI degradation pathway, or if cells are already adapted to minimal medium (MM) with MI, the lag phase is drastically shortened, and the bistable phenotype is abolished. We hypothesized that memory development or hysteresis is a further characteristic of MI degradation by S. Typhimurium; therefore, we investigated the transition from a short to a long lag phase in more detail. Growth experiments demonstrated that memory on the population level is successively lost within approximately 8 hr after cells, which had been adapted to MI utilization, were transferred to lysogeny broth (LB) medium. Flow cytometry (FC) analysis using a chromosomal fusion to PiolE , a promoter controlling the expression of the enzymatic genes iolE and iolG involved in MI degradation, indicated a gradual reversion within a few hours from a population in the "ON" status with respect to iolE transcription to one that is mainly in the "OFF" status. Growth and FC experiments revealed that IolR does not affect hysteresis.

  9. Crystal structure of a substrate complex of myo-inositol oxygenase, a di-iron oxygenase with a key role in inositol metabolism.

    PubMed

    Brown, Peter M; Caradoc-Davies, Tom T; Dickson, James M J; Cooper, Garth J S; Loomes, Kerry M; Baker, Edward N

    2006-10-10

    Altered metabolism of the inositol sugars myo-inositol (MI) and d-chiro-inositol is implicated in diabetic complications. In animals, catabolism of MI and D-chiro-inositol depends on the enzyme MI oxygenase (MIOX), which catalyzes the first committed step of the glucuronate-xylulose pathway, and is found almost exclusively in the kidneys. The crystal structure of MIOX, in complex with MI, has been determined by multiwavelength anomalous diffraction methods and refined at 2.0-A resolution (R=0.206, Rfree=0.253). The structure reveals a monomeric, single-domain protein with a mostly helical fold that is distantly related to the diverse HD domain superfamily. Five helices form the structural core and provide six ligands (four His and two Asp) for the di-iron center, in which the two iron atoms are bridged by a putative hydroxide ion and one of the Asp ligands, Asp-124. A key loop forms a lid over the MI substrate, which is coordinated in bidentate mode to one iron atom. It is proposed that this mode of iron coordination, and interaction with a key Lys residue, activate MI for bond cleavage. The structure also reveals the basis of substrate specificity and suggests routes for the development of specific MIOX inhibitors.

  10. Myo-inositol inhibits intestinal glucose absorption and promotes muscle glucose uptake: a dual approach study.

    PubMed

    Chukwuma, Chika Ifeanyi; Ibrahim, Mohammed Auwal; Islam, Md Shahidul

    2016-12-01

    The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC50 = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU50 = 2.68 ± 0.75 %) or without (GU50 = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products.

  11. The diabetic rat kidney mediates inosituria and selective urinary partitioning of D-chiro-inositol.

    PubMed

    Chang, Hao-Han; Choong, Bernard; Phillips, Anthony R J; Loomes, Kerry M

    2015-01-01

    Diabetic nephropathy is a serious complication of diabetes mellitus with a pressing need for effective metabolic markers to detect renal impairment. Of potential significance are the inositol compounds, myo-inositol (MI), and the less abundant stereoisomer, D-chiro-inositol (DCI), which are excreted at increased levels in the urine in diabetes mellitus, a phenomenon known as inosituria. There is also a selective urinary excretion of DCI compared to MI. As the biological origins of altered inositol metabolism in diabetes mellitus are unknown, the aim of this study was to determine whether the diabetic kidney was directly responsible. Kidneys isolated from four-week streptozotocin-induced diabetic rats were characterized by a 3-fold reduction in glomerular filtration rate (GFR) compared to matched non-diabetic kidneys. When perfused with fixed quantities of MI (50 µM) and DCI (5 µM) under normoglycemic conditions (5 mM glucose), GFR-normalized urinary excretion of MI was increased by 1.7-fold in diabetic vs. non-diabetic kidneys. By comparison, GFR-normalized urinary excretion of DCI was increased by 4-fold. Perfusion conditions replicating hyperglycemia (20 mM glucose) potentiated DCI but not MI urinary excretion in both non-diabetic and diabetic kidneys. Overall, there was a 2.4-fold increase in DCI urinary excretion compared to MI in diabetic kidneys that was independent of glucose ambience. This increased urinary excretion of DCI and MI in diabetic kidneys occurred despite increased renal expression of the inositol transporters, sodium myo-inositol transporter subtype 1 and 2 (SMIT1 and SMIT2). These findings show that the diabetic kidney primarily mediates inosituria and altered urinary partitioning of MI and DCI. Urinary inositol levels might therefore serve as an indicator of impaired renal function in diabetes mellitus with wider implications for monitoring chronic kidney disease.

  12. Tilapia (Oreochromis mossambicus) brain cells respond to hyperosmotic challenge by inducing myo-inositol biosynthesis.

    PubMed

    Gardell, Alison M; Yang, Jun; Sacchi, Romina; Fangue, Nann A; Hammock, Bruce D; Kültz, Dietmar

    2013-12-15

    This study aimed to determine the regulation of the de novo myo-inositol biosynthetic (MIB) pathway in Mozambique tilapia (Oreochromis mossambicus) brain following acute (25 ppt) and chronic (30, 60 and 90 ppt) salinity acclimations. The MIB pathway plays an important role in accumulating the compatible osmolyte, myo-inositol, in cells in response to hyperosmotic challenge and consists of two enzymes, myo-inositol phosphate synthase and inositol monophosphatase. In tilapia brain, MIB enzyme transcriptional regulation was found to robustly increase in a time (acute acclimation) or dose (chronic acclimation) dependent manner. Blood plasma osmolality and Na(+) and Cl(-) concentrations were also measured and significantly increased in response to both acute and chronic salinity challenges. Interestingly, highly significant positive correlations were found between MIB enzyme mRNA and blood plasma osmolality in both acute and chronic salinity acclimations. Additionally, a mass spectrometry assay was established and used to quantify total myo-inositol concentration in tilapia brain, which closely mirrored the hyperosmotic MIB pathway induction. Thus, myo-inositol is a major compatible osmolyte that is accumulated in brain cells when exposed to acute and chronic hyperosmotic challenge. These data show that the MIB pathway is highly induced in response to environmental salinity challenge in tilapia brain and that this induction is likely prompted by increases in blood plasma osmolality. Because the MIB pathway uses glucose-6-phosphate as a substrate and large amounts of myo-inositol are being synthesized, our data also illustrate that the MIB pathway likely contributes to the high energetic demand posed by salinity challenge.

  13. Tilapia (Oreochromis mossambicus) brain cells respond to hyperosmotic challenge by inducing myo-inositol biosynthesis

    PubMed Central

    Gardell, Alison M.; Yang, Jun; Sacchi, Romina; Fangue, Nann A.; Hammock, Bruce D.; Kültz, Dietmar

    2013-01-01

    SUMMARY This study aimed to determine the regulation of the de novo myo-inositol biosynthetic (MIB) pathway in Mozambique tilapia (Oreochromis mossambicus) brain following acute (25 ppt) and chronic (30, 60 and 90 ppt) salinity acclimations. The MIB pathway plays an important role in accumulating the compatible osmolyte, myo-inositol, in cells in response to hyperosmotic challenge and consists of two enzymes, myo-inositol phosphate synthase and inositol monophosphatase. In tilapia brain, MIB enzyme transcriptional regulation was found to robustly increase in a time (acute acclimation) or dose (chronic acclimation) dependent manner. Blood plasma osmolality and Na+ and Cl− concentrations were also measured and significantly increased in response to both acute and chronic salinity challenges. Interestingly, highly significant positive correlations were found between MIB enzyme mRNA and blood plasma osmolality in both acute and chronic salinity acclimations. Additionally, a mass spectrometry assay was established and used to quantify total myo-inositol concentration in tilapia brain, which closely mirrored the hyperosmotic MIB pathway induction. Thus, myo-inositol is a major compatible osmolyte that is accumulated in brain cells when exposed to acute and chronic hyperosmotic challenge. These data show that the MIB pathway is highly induced in response to environmental salinity challenge in tilapia brain and that this induction is likely prompted by increases in blood plasma osmolality. Because the MIB pathway uses glucose-6-phosphate as a substrate and large amounts of myo-inositol are being synthesized, our data also illustrate that the MIB pathway likely contributes to the high energetic demand posed by salinity challenge. PMID:24072790

  14. Polyphosphoinositide binding domains: Key to inositol lipid biology.

    PubMed

    Hammond, Gerald R V; Balla, Tamas

    2015-06-01

    Polyphosphoinositides (PPIn) are an important family of phospholipids located on the cytoplasmic leaflet of eukaryotic cell membranes. Collectively, they are critical for the regulation of many aspects of membrane homeostasis and signaling, with notable relevance to human physiology and disease. This regulation is achieved through the selective interaction of these lipids with hundreds of cellular proteins, and thus the capability to study these localized interactions is crucial to understanding their functions. In this review, we discuss current knowledge of the principle types of PPIn-protein interactions, focusing on specific lipid-binding domains. We then discuss how these domains have been re-tasked by biologists as molecular probes for these lipids in living cells. Finally, we describe how the knowledge gained with these probes, when combined with other techniques, has led to the current view of the lipids' localization and function in eukaryotes, focusing mainly on animal cells. This article is part of a Special Issue entitled Phosphoinositides.

  15. The Discovery of Carboxyethylpyrroles (CEPs): Critical Insights into AMD, Autism, Cancer, and Wound Healing from Basic Research on the Chemistry of Oxidized Phospholipids

    PubMed Central

    Salomon, Robert G.; Hong, Li; Hollyfield, Joe G.

    2011-01-01

    Basic research, exploring the hypothesis that 2-(ω-carboxyethyl)pyrrole (CEP) modifications of proteins are generated nonenzymatically in vivo is delivering a bonanza of molecular mechanistic insights into age-related macular degeneration, autism, cancer, and wound healing. CEPs are produced through covalent modification of protein lysyl ε-amino groups by γ-hydroxyalkenal phospholipids that are formed by oxidative cleavage of docosahexaenate-containing phospholipids. Chemical synthesis of CEP-modified proteins and the production of highly specific antibodies that recognize them preceded and facilitated their detection in vivo and enabled exploration of their biological occurrence and activities. This investigational approach –from the chemistry of biomolecules to disease phenotype – is proving to be remarkably productive. PMID:21875030

  16. Looking Beyond Structure: Membrane Phospholipids of Skeletal Muscle Mitochondria.

    PubMed

    Heden, Timothy D; Neufer, P Darrell; Funai, Katsuhiko

    2016-08-01

    Skeletal muscle mitochondria are highly dynamic and are capable of tremendous expansion to meet cellular energetic demands. Such proliferation in mitochondrial mass requires a synchronized supply of enzymes and structural phospholipids. While transcriptional regulation of mitochondrial enzymes has been extensively studied, there is limited information on how mitochondrial membrane lipids are generated in skeletal muscle. Herein we describe how each class of phospholipids that constitute mitochondrial membranes are synthesized and/or imported, and summarize genetic evidence indicating that membrane phospholipid composition represents a significant modulator of skeletal muscle mitochondrial respiratory function. We also discuss how skeletal muscle mitochondrial phospholipids may mediate the effect of diet and exercise on oxidative metabolism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Herpes simplex virus 1 induces de novo phospholipid synthesis

    SciTech Connect

    Sutter, Esther; Oliveira, Anna Paula de; Tobler, Kurt; Schraner, Elisabeth M.; Sonda, Sabrina; Kaech, Andres; Lucas, Miriam S.; Ackermann, Mathias; Wild, Peter

    2012-08-01

    Herpes simplex virus type 1 capsids bud at nuclear membranes and Golgi membranes acquiring an envelope composed of phospholipids. Hence, we measured incorporation of phospholipid precursors into these membranes, and quantified changes in size of cellular compartments by morphometric analysis. Incorporation of [{sup 3}H]-choline into both nuclear and cytoplasmic membranes was significantly enhanced upon infection. [{sup 3}H]-choline was also part of isolated virions even grown in the presence of brefeldin A. Nuclei expanded early in infection. The Golgi complex and vacuoles increased substantially whereas the endoplasmic reticulum enlarged only temporarily. The data suggest that HSV-1 stimulates phospholipid synthesis, and that de novo synthesized phospholipids are inserted into nuclear and cytoplasmic membranes to i) maintain membrane integrity in the course of nuclear and cellular expansion, ii) to supply membrane constituents for envelopment of capsids by budding at nuclear membranes and Golgi membranes, and iii) to provide membranes for formation of transport vacuoles.

  18. Phospholipids of the lung in normal, toxic, and diseased states

    SciTech Connect

    Akino, T.; Ohno, K.

    1981-01-01

    The highly pulmonary concentration of 1,2-dipalmitoyl-sn-glycerol-3-phosphorylcholine (dipalmitoyllecithin) and its implication as an important component of lung surfactant have promoted investigation of phospholipid metabolism in the lung. This review will set the contents including recent informations for better understanding of phospholipid metabolism of the lung in normal state (physiological significances of lung phospholipids, characteristics of phospholipids in lung tissue and alveolar washing, biosynthetic pathways of dipalmitoyllecithin, etc.) as well as in toxic states (pulmonary oxygen toxicity, etc.) and in diseased states (idiopathic respiratory distress syndrome, pulmonary alveolar proteinosis, etc.) Since our main concern has been to clarify the most important route for supplying dipalmitoyllecithin, this review will be focused upon the various biosynthetic pathways leading to the formation of different molecular species of lecithin and their potential significance in the normal, toxic, and diseased lungs.

  19. Supported phospholipid/alkanethiol biomimetic membranes: insulating properties.

    PubMed Central

    Plant, A L; Gueguetchkeri, M; Yap, W

    1994-01-01

    A novel model lipid bilayer membrane is prepared by the addition of phospholipid vesicles to alkanethiol monolayers on gold. This supported hybrid bilayer membrane is rugged, easily and reproducibly prepared in the absence of organic solvent, and is stable for very long periods of time. We have characterized the insulating characteristics of this membrane by examining the rate of electron transfer and by impedance spectroscopy. Supported hybrid bilayers formed from phospholipids and alkanethiols are pinhole-free and demonstrate measured values of conductivity and resistivity which are within an order of magnitude of that reported for black lipid membranes. Capacitance values suggest a dielectric constant of 2.7 for phospholipid membranes in the absence of organic solvent. The protein toxin, melittin, destroys the insulating capability of the phospholipid layer without significantly altering the bilayer structure. This model membrane will allow the assessment of the effect of lipid membrane perturbants on the insulating properties of natural lipid membranes. PMID:7811924

  20. Biomolecular interactions at phospholipid-decorated surfaces of liquid crystals.

    PubMed

    Brake, Jeffrey M; Daschner, Maren K; Luk, Yan-Yeung; Abbott, Nicholas L

    2003-12-19

    The spontaneous assembly of phospholipids at planar interfaces between thermotropic liquid crystals and aqueous phases gives rise to patterned orientations of the liquid crystals that reflect the spatial and temporal organization of the phospholipids. Strong and weak specific-binding events involving proteins at these interfaces drive the reorganization of the phospholipids and trigger orientational transitions in the liquid crystals. Because these interfaces are fluid, processes involving the lateral organization of proteins (such as the formation of protein- and phospholipid-rich domains) are also readily imaged by the orientational response of the liquid crystal, as are stereospecific enzymatic events. These results provide principles for label-free monitoring of aqueous streams for molecular and biomolecular species without the need for complex instrumentation.

  1. A phospholipid uptake system in the model plant Arabidopsis thaliana.

    PubMed

    Poulsen, Lisbeth R; López-Marqués, Rosa L; Pedas, Pai R; McDowell, Stephen C; Brown, Elizabeth; Kunze, Reinhard; Harper, Jeffrey F; Pomorski, Thomas G; Palmgren, Michael

    2015-07-27

    Plants use solar energy to produce lipids directly from inorganic elements and are not thought to require molecular systems for lipid uptake from the environment. Here we show that Arabidopsis thaliana Aminophospholipid ATPase10 (ALA10) is a P4-type ATPase flippase that internalizes exogenous phospholipids across the plasma membrane, after which they are rapidly metabolized. ALA10 expression and phospholipid uptake are high in the epidermal cells of the root tip and in guard cells, the latter of which regulate the size of stomatal apertures to modulate gas exchange. ALA10-knockout mutants exhibit reduced phospholipid uptake at the root tips and guard cells and are affected in growth and transpiration. The presence of a phospholipid uptake system in plants is surprising. Our results suggest that one possible physiological role of this system is to internalize lysophosphatidylcholine, a signalling lipid involved in root development and stomatal control.

  2. Stereo- and regiospecificity of yeast phytases-chemical synthesis and enzymatic conversion of the substrate analogues neo- and L-chiro-inositol hexakisphosphate.

    PubMed

    Adelt, Stephan; Podeschwa, Michael; Dallmann, Guido; Altenbach, Hans-Josef; Vogel, Günter

    2003-02-01

    Phytases are enzymes that catalyze the hydrolysis of phosphate esters in myo-inositol hexakisphosphate (phytic acid). The precise routes of enzymatic dephosphorylation by phytases of the yeast strains Saccharomyces cerevisiae and Pichia rhodanensis have been investigated up to the myo-inositol trisphosphate level, including the absolute configuration of the intermediates. Stereoselective assignment of the myo-inositol pentakisphosphates (D-myo-inositol 1,2,4,5,6-pentakisphosphate and D-myo-inositol 1,2,3,4,5-pentakisphosphate) generated was accomplished by a new method based on enantiospecific enzymatic conversion and HPLC analysis. Via conduritol B or E derivatives the total syntheses of two epimers of myo-inositol hexakisphosphate, neo-inositol hexakisphosphate and L-chiro-inositol hexakisphosphate were performed to examine the specificity of the yeast phytases with these substrate analogues. A comparison of kinetic data and the degradation pathways determined gave the first hints about the molecular recognition of inositol hexakisphosphates by the enzymes. Exploitation of the high stereo- and regiospecificity observed in the dephosphorylation of neo- and L-chiro-inositol hexakisphosphate made it possible to establish enzyme-assisted steps for the synthesis of D-neo-inositol 1,2,5,6-tetrakisphosphate, L-chiro-inositol 1,2,3,5,6-pentakisphosphate and L-chiro-inositol 1,2,3,6-tetrakisphosphate.

  3. Regional distribution of phospholipids in porcine vitreous humor.

    PubMed

    Schnepf, Abigail; Yappert, Marta Cecilia; Borchman, Douglas

    2017-07-01

    This project explores the regional phospholipid distribution in porcine vitreous humor, retina, and lens. Matrix-assisted laser desorption mass spectrometry has been used previously to image lipids, proteins, and other metabolites in retinas and lenses. However, the regional composition of phospholipids in vitreous humors is not known. To address this issue, we have applied this mass spectral method to explore the regional phospholipid distribution in porcine vitreous humor both ex-situ and in-vitro. To establish the possible source(s) of phospholipids in the vitreous humor, compositional studies of the lens and retina were also pursued. Due to the overall low levels of phospholipids in vitreous humor, it was necessary to optimize the experimental approaches for ex-situ and in-vitro studies. The sensitivity observed in the spectra of methanol extracts from the lens and retina was higher than that for methanol:chloroform extracts, but the compositional trends were the same. A fourfold improvement in sensitivity was observed in the analysis of vitreous humor extracts obtained with the Bligh and Dyer protocol relative to the other two extraction methods. For ex-situ studies, the 'stamp method' with para-nitroaniline as the matrix was chosen. Throughout the vitreous humor, phosphatidylcholines were the most abundant phospholipids. In-vitro results showed higher relative levels of phospholipids compared to the 'stamp' method. However, more details in the regional phospholipid distribution were provided by the ex-situ approach. Both in-vitro and ex-situ results indicated higher levels of phospholipids in the posterior vitreous region, followed by the anterior and central regions. The posterior region contained more unsaturated species whereas more saturated phospholipids were detected in the anterior region. The observed trends suggest that the phospholipids detected in the posterior vitreous humor migrate from the retina and associated vasculature while those present in

  4. Molecular definition of a novel inositol polyphosphate metabolic pathway initiated by inositol 1,4,5-trisphosphate 3-kinase activity in Saccharomyces cerevisiae.

    PubMed

    Seeds, Andrew M; Bastidas, Robert J; York, John D

    2005-07-29

    The production of inositol polyphosphate (IPs) and pyrophosphates (PP-IPs) from inositol 1,4,5-trisphosphate (I(1,4,5)P3) requires the 6-/3-/5-kinase activity of Ipk2 (also known as Arg82 and inositol polyphosphate multikinase). Here, we probed the distinct roles for I(1,4,5)P3 6- versus 3-kinase activities in IP metabolism and cellular functions reported for Ipk2. Expression of either I(1,4,5)P3 6- or 3-kinase activity rescued growth of ipk2-deficient yeast at high temperatures, whereas only 6-kinase activity enabled growth on ornithine as the sole nitrogen source. Analysis of IP metabolism revealed that the 3-kinase initiated the synthesis of novel pathway consisting of over eleven IPs and PP-IPs. This pathway was present in wild-type and ipk2 null cells, albeit at low levels as compared with inositol hexakisphosphate synthesis. The primary route of synthesis was: I(1,4,5)P3 --> I(1,3,4,5)P4 --> I(1,2,3,4,5)P5 --> PP-IP4 --> PP2-IP3 and required Kcs1 (or possibly Ipk2), Ipk1, a novel inositol pyrophosphate synthase, and then Kcs1 again, respectively. Mutation of kcs1 ablated this pathway in ipk2 null cells and overexpression of Kcs1 in ipk2 mutant cells phenocopied IP3K expression, confirming it harbors a novel 3-kinase activity. Our work provides a revised genetic map of IP metabolism in yeast and evidence for dosage compensation between IPs and PP-IPs downstream of I(1,4,5)P3 in the regulation of nucleocytoplasmic processes.

  5. Delayed oxidative degradation of polyunsaturated diacyl phospholipids in the presence of plasmalogen phospholipids in vitro.

    PubMed Central

    Reiss, D; Beyer, K; Engelmann, B

    1997-01-01

    The oxidative degradation of plasmalogen (alkenylacyl) phospholipids was analysed in the absence and the presence of polyunsaturated ester phospholipids by 1H-NMR and by chemical determination. Brain lysoplasmenylethanolamine (lyso-P-PE), brain P-PE and erythrocyte P-PE, containing an increasing number of intrachain double bonds at sn2, were oxidized with 2,2'-azobis-(2-amidinopropane hydrochloride) (AAPH; 2 or 10 mM) in Triton X-100 micelles (detergent/phospholipid 1:5, mol/mol). The formation of two peroxyl radicals was accompanied by the degradation of approx. one molecule of brain lyso-P-PE. On oxidation of brain P-PE or erythrocyte P-PE (320 nmol) with 2 mM AAPH, the (alpha-vinyl) methine 1H signal of the enol ether decreased more rapidly than the methine proton peak of intrachain double bonds. The rate of enol ether degradation increased in the order: erythrocyte P-PE>brain P-PE>brain lyso-P-PE. The disappearance of the polyunsaturated ester phospholipids 1-palmitoyl-2-arachidonoyl phosphatidylcholine (16:0/20:4-PC) and 1-palmitoyl-2-linoleoyl phosphatidylcholine (16:0/18:2-PC) (100 nmol), as induced by 10 mM AAPH, was nearly completely inhibited by the plasmalogens (25 nmol) in the first 30 and 60 min of incubation respectively, and was delayed at later time points. Plasmalogens and vitamin E (4-25 nmol) mitigated the decreases in 16:0/[3H]20:4-PC (100 nmol) induced by 2 mM AAPH in a similar manner. The initial rate of degradation of intrachain double bonds of 16:0/20:4-PC and 16:0/18:2-PC (320 nmol; 2 mM AAPH) was decreased by 59% and 81% respectively in the presence of 80 nmol of brain lyso-P-PE. In conclusion, plasmalogens markedly delay the oxidative degradation of intrachain double bonds under in vitro conditions. Interactions of enol ether double bonds with initiating peroxyl radicals as well as with products generated by prior oxidation of polyunsaturated fatty acids are proposed to be responsible for this capacity of plasmalogens. Furthermore, the

  6. Enhancement by cytidine of membrane phospholipid synthesis

    NASA Technical Reports Server (NTRS)

    G-Coviella, I. L.; Wurtman, R. J.

    1992-01-01

    Cytidine, as cytidine 5'-diphosphate choline, is a major precursor in the synthesis of phosphatidylcholine in cell membranes. In the present study, we examined the relationships between extracellular levels of cytidine, the conversion of [14C]choline to [14C]phosphatidylcholine, and the net syntheses of phosphatidylcholine and phosphatidylethanolamine by PC12 cells. The rate at which cytidine (as [3H]cytidine) was incorporated into the PC12 cells followed normal Michaelis-Menten kinetics (Km = 5 microM; Vmax = 12 x 10(-3) mmol/mg of protein/min) when the cytidine concentrations in the medium were below 50 microM; at higher concentrations, intracellular [3H]cytidine nucleotide levels increased linearly. Once inside the cell, cytidine was converted mainly into cytidine triphosphate. In pulse-chase experiments, addition of cytidine to the medium caused a time- and dose-dependent increase (by up to 30%) in the incorporation of [14C]choline into membrane [14C]-phosphatidylcholine. When the PC12 cells were supplemented with both cytidine and choline for 14 h, small but significant elevations (p less than 0.05) were observed in their absolute contents of membrane phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine, all increasing by 10-15% relative to their levels in cells incubated with choline alone. Exogenous cytidine, acting via cytidine triphosphate, can thus affect the synthesis and levels of cell membrane phospholipids.

  7. Tissue phospholipids (TPL) in avian tuberculosis (AT)

    SciTech Connect

    Nandedkar, A.K.N.; Malhotra, H.C.

    1986-05-01

    AT constitutes one of the major problems in animal husbandry. Chickens (white, leg horn, male, 400-600 g) were infected with Mycobacterium avium maintained on I.U.T. medium to induce clinical AT which was confirmed by histopathological examinations of the affected tissues. Fatty infiltration and tissue enlargement was visible in infected birds. After 4 wks, incorporation of i.v. /sup 32/P (50 uCi/100 g body wt.) in affected tissues was followed for 3,7,9,12 hr intervals. Lipids were extracted and fractionated by silicic acid (SA) column and SA impregnated paper chromatography. When compared with pair-fed controls, in AT slower turnover of TPL in liver, slightly higher in heart and significantly increased turnover of TPL in serum were observed. No appreciable change in total TPL content was noticed in brain, spleen and kidney. Further fractionation of TPL provided better understanding of the metabolism. Increase in lysophosphatidyl-choline (LPC) and -ethanolamine (LPE) content, powerful hemolytic agents, in liver may explain frequent occurrence of anemia in tuberculosis. Also, a concomitant marked increase in the ratio of total saturated/unsaturated fatty acids is observed in serum phosphatidyl choline fraction. This confirms the observation that the membrane phospholipid metabolism is significantly affected in tuberculosis infection.

  8. Molecular Insights into Phospholipid -- NSAID Interactions

    NASA Astrophysics Data System (ADS)

    Babu Boggara, Mohan; Krishnamoorti, Ramanan

    2007-03-01

    Non steroidal anti inflammatory drugs (NSAIDs) e.g. Aspirin and Ibuprofen, with chronic usage cause gastro intestinal (GI) toxicity. It has been shown experimentally that NSAIDs pre-associated with phospholipids reduce the GI toxicity and also increase the therapeutic activity of these drugs compared to the unmodified ones. Using all atomistic simulations and two different methodologies, we studied the partitioning behavior of two model NSAIDs (Aspirin and Ibuprofen) as a function of pH and drug loading. The results from two methodologies are consistent in describing the equilibrium drug distribution in the bilayers. Additionally, the heterogeneity in density and polarity of the bilayer in the normal direction along with the fact that NSAIDs are amphiphilic (all of them have a carboxylic acid group and a non-polar part consisting of aromatic moieties), indicate that the diffusion mechanism in the bilayer is far different compared to the same in a bulk medium. This study summarizes the various effects of NSAIDs and their behavior inside the lipid bilayer both as a function of pH and drug concentration.

  9. Millimeter-area, free standing, phospholipid bilayers.

    PubMed

    Beltramo, Peter J; Van Hooghten, Rob; Vermant, Jan

    2016-05-11

    Minimal model biomembrane studies have the potential to unlock the fundamental mechanisms of cellular function that govern the processes upon which life relies. However, existing methods to fabricate free-standing model membranes currently have significant limitations. Bilayer sizes are often tens of micrometers, decoupling curvature or substrate effects, orthogonal control over tension, and solvent exchange combined with microscopy techniques is not possible, which restricts the studies that can be performed. Here, we describe a versatile platform to generate free standing, planar, phospholipid bilayers with millimeter scale areas. The technique relies on an adapted thin-film balance apparatus allowing for the dynamic control of the nucleation and growth of a planar black lipid membrane in the center of an orifice surrounded by microfluidic channels. Success is demonstrated using several different lipid types, including mixtures that show the same temperature dependent phase separation as existing protocols, moreover, membranes are highly stable. Two advantages unique to the proposed method are the dynamic control of the membrane tension and the possibility to make extremely large area membranes. We demonstrate this by showing how a block polymer, F68, used in drug delivery increases the membrane compliance. Together, the results demonstrate a new paradigm for studying the mechanics, structure, and function of model membranes.

  10. Enhancement by cytidine of membrane phospholipid synthesis

    NASA Technical Reports Server (NTRS)

    G-Coviella, I. L.; Wurtman, R. J.

    1992-01-01

    Cytidine, as cytidine 5'-diphosphate choline, is a major precursor in the synthesis of phosphatidylcholine in cell membranes. In the present study, we examined the relationships between extracellular levels of cytidine, the conversion of [14C]choline to [14C]phosphatidylcholine, and the net syntheses of phosphatidylcholine and phosphatidylethanolamine by PC12 cells. The rate at which cytidine (as [3H]cytidine) was incorporated into the PC12 cells followed normal Michaelis-Menten kinetics (Km = 5 microM; Vmax = 12 x 10(-3) mmol/mg of protein/min) when the cytidine concentrations in the medium were below 50 microM; at higher concentrations, intracellular [3H]cytidine nucleotide levels increased linearly. Once inside the cell, cytidine was converted mainly into cytidine triphosphate. In pulse-chase experiments, addition of cytidine to the medium caused a time- and dose-dependent increase (by up to 30%) in the incorporation of [14C]choline into membrane [14C]-phosphatidylcholine. When the PC12 cells were supplemented with both cytidine and choline for 14 h, small but significant elevations (p less than 0.05) were observed in their absolute contents of membrane phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine, all increasing by 10-15% relative to their levels in cells incubated with choline alone. Exogenous cytidine, acting via cytidine triphosphate, can thus affect the synthesis and levels of cell membrane phospholipids.

  11. Biomimetic surface modification of polyurethane with phospholipids grafted carbon nanotubes.

    PubMed

    Tan, Dongsheng; Liu, Liuxu; Li, Zhen; Fu, Qiang

    2015-08-01

    To improve blood compatibility of polyurethane (PU), phospholipids grafted carbon nanotubes (CNTs) were prepared through zwitterion-mediated cycloaddition reaction and amide condensation, and then were added to the PU as fillers via solution mixing to form biomimetic surface. The properties of phospholipids grafted CNTs (CNT-PC) were investigated by thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance ((1) H NMR). The results indicated that the phospholipids were grafted onto CNTs in high efficiency, and the hydrophilicity and dispersibility of the modified CNTs were improved effectively. The structures and properties of composites containing CNT-PC were investigated by optical microscope, XPS, and water contact angles. The results indicated that phospholipids were enriched on the surface with addition of 0.1 wt % of CNT-PC, which significantly reduced protein adsorption and platelet adhesion. The method of carrying phospholipids on the nanofiller to modify polymers has provided a promising way of constructing biomimetic phospholipid membrane on the surface to improve blood compatibility.

  12. Effects of Phenethyl Alcohol on Phospholipid Metabolism in Escherichia coli

    PubMed Central

    Nunn, William D.; Tropp, Burton E.

    1972-01-01

    The incorporation of labeled precursors into the deoxyribonucleic acid, ribonucleic acid (RNA), proteins, and phospholipids of Escherichia coli cultured in the presence of phenethyl alcohol (PEA) was determined. PEA inhibited the uptake of labeled uracil to the same extent in cells exhibiting relaxed and stringent control of RNA synthesis. This indicates that PEA does not primarily affect amino acid synthesis or activation. Uptake of labeled acetate into the phospholipid fraction was more sensitive to inhibition by low concentrations of PEA than was the uptake of labeled precursors into the macromolecules. Thymine starvation or the addition of nalidixic acid (10 μg/ml) had no effect on acetate incorporation. Chloramphenicol (25 μg/ml) was a much less effective inhibitor of acetate incorporation than was PEA. The distribution of labeled acetate incorporated into phospholipids was markedly affected by the presence of PEA. The uptake of acetate into phosphatidylethanolamine and phosphatidylglycerol was inhibited, whereas the uptake of acetate into the cardiolipin fraction was unaffected. Since acetate incorporation into phospholipid was quite sensitive to PEA, we suggest that the PEA-sensitive component required for the initiation of replication may be a phospholipid(s). PMID:4550658

  13. Polyglutamine expansion in huntingtin alters its interaction with phospholipids.

    PubMed

    Kegel, Kimberly B; Sapp, Ellen; Alexander, Jonathan; Valencia, Antonio; Reeves, Patrick; Li, Xueyi; Masso, Nicholas; Sobin, Lindsay; Aronin, Neil; DiFiglia, Marian

    2009-09-01

    Huntingtin has an expanded polyglutamine tract in patients with Huntington's disease. Huntingtin localizes to intracellular and plasma membranes but the function of huntingtin at membranes is unknown. Previously we reported that exogenously expressed huntingtin bound pure phospholipids using protein-lipid overlays. Here we show that endogenous huntingtin from normal (Hdh(7Q/7Q)) mouse brain and mutant huntingtin from Huntington's disease (Hdh(140Q/140Q)) mouse brain bound to large unilamellar vesicles containing phosphoinositol (PI) PI 3,4-bisphosphate, PI 3,5-bisphosphate, and PI 3,4,5-triphosphate [PI(3,4,5)P3]. Huntingtin interactions with multivalent phospholipids were similar to those of dynamin. Mutant huntingtin associated more with phosphatidylethanolamine and PI(3,4,5)P3 than did wild-type huntingtin, and associated with other phospholipids not recognized by wild-type huntingtin. Wild-type and mutant huntingtin also bound to large unilamellar vesicles containing cardiolipin, a phospholipid specific to mitochondrial membranes. Maximal huntingtin-phospholipid association required inclusion of huntingtin amino acids 171-287. Endogenous huntingtin recruited to the plasma membrane in cells that incorporated exogenous PI 3,4-bisphosphate and PI(3,4,5)P3 or were stimulated by platelet-derived growth factor or insulin growth factor 1, which both activate PI 3-kinase. These data suggest that huntingtin interacts with membranes through specific phospholipid associations and that mutant huntingtin may disrupt membrane trafficking and signaling at membranes.

  14. Microtubes and nanotubes of a phospholipid bilayer membrane

    NASA Astrophysics Data System (ADS)

    Kralj-Iglic, Veronika; Iglic, Ales; Gomiscek, Gregor; Sevsek, France; Arrigler, Vesna; Hägerstrand, Henry

    2002-02-01

    We propose a theory describing the stable structure of a phospholipid bilayer in pure water involving a spherical mother vesicle with long thin tubular protrusion. It is considered that the phospholipid molecules are in general anisotropic with respect to the axis normal to the membrane and can orient in the plane of the membrane if the curvature field is strongly anisotropic. Taking this into account, the membrane free energy is derived starting from a single-molecule energy and using methods of statistical mechanics. By linking the description on the microscopic level with the continuum theory of elasticity we recover the expression for the membrane bending energy and obtain an additional (deviatoric) contribution due to the orientational ordering of the phospholipid molecules. It is shown that the deviatoric contribution may considerably decrease the phospholipid vesicle membrane free energy if the vesicle involves regions where the difference between the two principal curvatures is large (thin cylindrical protrusions and/or thin finite necks) and thereby yields a possible explanation for the stability of the long thin tubular protrusions of the phospholipid bilayer vesicles. We report on the experiment exhibiting a stable shape of the spherical phospholipid vesicle with a long thin tubular protrusion in pure water.

  15. Coupling of Fatty Acid and Phospholipid Synthesis in Bacillus subtilis▿

    PubMed Central

    Paoletti, Luciana; Lu, Ying-Jie; Schujman, Gustavo E.; de Mendoza, Diego; Rock, Charles O.

    2007-01-01

    plsX (acyl-acyl carrier protein [ACP]:phosphate acyltransferase), plsY (yneS) (acyl-phosphate:glycerol-phosphate acyltransferase), and plsC (yhdO) (acyl-ACP:1-acylglycerol-phosphate acyltransferase) function in phosphatidic acid formation, the precursor to membrane phospholipids. The physiological functions of these genes was inferred from their in vitro biochemical activities, and this study investigated their roles in gram-positive phospholipid metabolism through the analysis of conditional knockout strains in the Bacillus subtilis model system. The depletion of PlsX led to the cessation of both fatty acid synthesis and phospholipid synthesis. The inactivation of PlsY also blocked phospholipid synthesis, but fatty acid formation continued due to the appearance of acylphosphate intermediates and fatty acids arising from their hydrolysis. Phospholipid synthesis ceased following PlsC depletion, but fatty acid synthesis continued at a high rate, leading to the accumulation of fatty acids arising from the dephosphorylation of 1-acylglycerol-3-P followed by the deacylation of monoacylglycerol. Analysis of glycerol 3-P acylation in B. subtilis membranes showed that PlsY was an acylphosphate-specific acyltransferase, whereas PlsC used only acyl-ACP as an acyl donor. PlsX was found in the soluble fraction of disrupted cells but was associated with the cell membrane in intact organisms. These data establish that PlsX is a key enzyme that coordinates the production of fatty acids and membrane phospholipids in B. subtilis. PMID:17557823

  16. Preceding trauma in childhood hematogenous bone and joint infections.

    PubMed

    Pääkkönen, Markus; Kallio, Markku J T; Lankinen, Petteri; Peltola, Heikki; Kallio, Pentti E

    2014-03-01

    Preceding trauma may play a role in the etiology and pathogenesis of hematogenous bone and joint infections. Among 345 children with an acute hematogenous bone and/or joint infection, 20% reported trauma during a 2-week period leading to infection. Blunt impact, bruises, or excoriations were commonly reported. The rate was similar to that in the general pediatric population obtained from the literature. In the study group, patients with and without trauma were similar in age, serum C-reactive protein and erythrocyte sedimentation rate, length of hospitalization, and late sequelae. Preceding minor trauma did not prove to be significant as an etiological or as a prognostic factor.

  17. Inositol 1,3,4,5-tetrakisphosphate as a mediator of neuronal death in ischemic hippocampus.

    PubMed

    Tsubokawa, H; Oguro, K; Robinson, H P; Masuzawa, T; Rhee, T S; Takenawa, T; Kawai, N

    1994-03-01

    Selective death of CA1 pyramidal neurons after transient forebrain ischemia has attracted interest for its possible relation to the pathogenesis of memory deficits and dementia. Using whole cell patch-clamp recording from CA1 pyramidal neurons in hippocampal slices of gerbils after ischemia we studied the intracellular signaling mechanisms related to the phosphoinositide cycle. Intracellular application of an antibody against phosphatidylinositol 4,5-bisphosphate rescued ischemic neurons from stimulus-induced irreversible depolarization. Furthermore, application of inositol 1,3,4,5-tetrakisphosphate in normal cells caused an irreversible depolarization in response to synaptic input, which mimicked the deterioration of ischemic neurons. Depolarization of both ischemic and normal neurons in the presence of inositol 1,3,4,5-tetrakisphosphate was prevented by the addition of the Ca2+ chelator, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetate. Application of antibody against inositol 1,4,5-triphosphate 3-kinase, which blocks formation of inositol 1,3,4,5-tetrakisphosphate, also protected against cell deterioration. Our results suggest that the vulnerability of hippocampal pyramidal neurons following ischemia is caused by a disturbed phosphoinositide cascade, with one metabolite, inositol 1,3,4,5-tetrakisphosphate, playing a key role in the induction of Ca2+ accumulation, which leads to neuronal death.

  18. Simulations of inositol phosphate metabolism and its interaction with InsP(3)-mediated calcium release.

    PubMed Central

    Mishra, Jyoti; Bhalla, Upinder S

    2002-01-01

    Inositol phosphates function as second messengers for a variety of extracellular signals. Ins(1,4,5)P(3) generated by phospholipase C-mediated hydrolysis of phosphatidylinositol bisphosphate, triggers numerous cellular processes by regulating calcium release from internal stores. The Ins(1,4,5)P(3) signal is coupled to a complex metabolic cascade involving a series of phosphatases and kinases. These enzymes generate a range of inositol phosphate derivatives, many of which have signaling roles of their own. We have integrated published biochemical data to build a mass action model for InsP(3) metabolism. The model includes most inositol phosphates that are currently known to interact with each other. We have used this model to study the effects of a G-protein coupled receptor stimulus that activates phospholipase C on the inositol phosphates. We have also monitored how the metabolic cascade interacts with Ins(1,4,5)P(3)-mediated calcium release. We find temporal dynamics of most inositol phosphates to be strongly influenced by the elaborate networking. We also show that Ins(1,3,4,5)P(4) plays a key role in InsP(3) dynamics and allows for paired pulse facilitation of calcium release. Calcium oscillations produce oscillatory responses in parts of the metabolic network and are in turn temporally modulated by the metabolism of InsP(3). PMID:12202356

  19. Asymmetric distribution of glucose and indole-3-acetyl-myo-inositol in geostimulated Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Momonoki, Y. S.; Bandurski, R. S. (Principal Investigator)

    1988-01-01

    Indole-3-acetyl-myo-inositol occurs in both the kernel and vegetative shoot of germinating Zea mays seedlings. The effect of a gravitational stimulus on the transport of [3H]-5-indole-3-acetyl-myo-inositol and [U-14C]-D-glucose from the kernel to the seedling shoot was studied. Both labeled glucose and labeled indole-3-acetyl-myo-inositol become asymmetrically distributed in the mesocotyl cortex of the shoot with more radioactivity occurring in the bottom half of a horizontally placed seedling. Asymmetric distribution of [3H]indole-3-acetic acid, derived from the applied [3H]indole-3-acetyl-myo-inositol, occurred more rapidly than distribution of total 3H-radioactivity. These findings demonstrate that the gravitational stimulus can induce an asymmetric distribution of substances being transported from kernel to shoot. They also indicate that, in addition to the transport asymmetry, gravity affects the steady state amount of indole-3-acetic acid derived from indole-3-acetyl-myo-inositol.

  20. Metabolism and Ovarian Function in PCOS Women: A Therapeutic Approach with Inositols

    PubMed Central

    Rossetti, Paola; Buscema, Massimo; Condorelli, Rosita Angela; Gullo, Giuseppe; Triolo, Onofrio

    2016-01-01

    Polycystic ovary syndrome (PCOS) is characterized by chronical anovulation and hyperandrogenism which may be present in a different degree of severity. Insulin-resistance and hyperinsulinemia are the main physiopathological basis of this syndrome and the failure of inositol-mediated signaling may concur to them. Myo (MI) and D-chiro-inositol (DCI), the most studied inositol isoforms, are classified as insulin sensitizers. In form of glycans, DCI-phosphoglycan and MI-phosphoglycan control key enzymes were involved in glucose and lipid metabolism. In form of phosphoinositides, they play an important role as second messengers in several cellular biological functions. Considering the key role played by insulin-resistance and androgen excess in PCOS patients, the insulin-sensitizing effects of both MI and DCI were tested in order to ameliorate symptoms and signs of this syndrome, including the possibility to restore patients' fertility. Accumulating evidence suggests that both isoforms of inositol are effective in improving ovarian function and metabolism in patients with PCOS, although MI showed the most marked effect on the metabolic profile, whereas DCI reduced hyperandrogenism better. The purpose of this review is to provide an update on inositol signaling and correlate data on biological functions of these multifaceted molecules, in view of a rational use for the therapy in women with PCOS. PMID:27579037

  1. Genetic variants in the inositol phosphate metabolism pathway and risk of different types of cancer.

    PubMed

    Tan, Juan; Yu, Chen-Yang; Wang, Zhen-Hua; Chen, Hao-Yan; Guan, Jian; Chen, Ying-Xuan; Fang, Jing-Yuan

    2015-02-16

    Members of the inositol phosphate metabolism pathway regulate cell proliferation, migration and phosphatidylinositol-3-kinase (PI3K)/Akt signaling, and are frequently dysregulated in cancer. Whether germline genetic variants in inositol phosphate metabolism pathway are associated with cancer risk remains to be clarified. We examined the association between inositol phosphate metabolism pathway genes and risk of eight types of cancer using data from genome-wide association studies. Logistic regression models were applied to evaluate SNP-level associations. Gene- and pathway-based associations were tested using the permutation-based adaptive rank-truncated product method. The overall inositol phosphate metabolism pathway was significantly associated with risk of lung cancer (P = 2.00 × 10(-4)), esophageal squamous cell carcinoma (P = 5.70 × 10(-3)), gastric cancer (P = 3.03 × 10(-2)) and renal cell carcinoma (P = 1.26 × 10(-2)), but not with pancreatic cancer (P = 1.40 × 10(-1)), breast cancer (P = 3.03 × 10(-1)), prostate cancer (P = 4.51 × 10(-1)), and bladder cancer (P = 6.30 × 10(-1)). Our results provide a link between inherited variation in the overall inositol phosphate metabolism pathway and several individual genes and cancer. Further studies will be needed to validate these positive findings, and to explore its mechanisms.

  2. Purification and properties of myo-inositol-1-phosphate dehydrogenase from germinating mung bean seeds.

    PubMed

    Ghosh, B; De, B P; Biswas, B B

    1984-01-01

    A novel enzyme, myo-inositol-1-phosphate dehydrogenase, which catalyzes the conversion of myo-inositol 1-phosphate to ribulose 5-phosphate has been purified 84-fold from mung bean seedling employing several common techniques. The molecular weight of this purified enzyme has been recorded as 88,500 by Sephadex G-200 column chromatography, and in sodium dodecyl sulfate-polyacrylamide gel electrophoresis one protein band containing three subunits of Mr 32,000 each was discernible. Km values for NAD+ and myo-inositol 1-phosphate have been recorded as 2.8 X 10(-4) and 5.0 X 10(-4) M, respectively. Production of NADH in myo-inositol-1-phosphate dehydrogenase reaction has also been evidenced by measurement of NADH fluorescence. Dehydrogenation and decarboxylation of myo-inositol 1-phosphate are mediated by the same enzyme. In fact, the rate of dehydrogenation corroborates with that of decarboxylation. Stoichiometry of this reaction suggests that for the production of 1 mol of ribulose 5-phosphate 2 mol of NAD+ are reduced.

  3. Thermoanalytical study of sweetener myo-inositol: α and β polymorphs.

    PubMed

    Alarcon, Rafael Turra; Gaglieri, Caroline; Caires, Flávio Junior; Magdalena, Aroldo Geraldo; de Castro, Ricardo António Esteves; Bannach, Gilbert

    2017-12-15

    This work investigates the thermal behavior of α and β myo-inositol polymorphs. The inositol is a natural compound widely used in the food industry due to its presence in carbohydrate metabolism and its sweet taste. The occurrence of polymorphism could change some physico-chemical properties, such as melting and sublimation temperatures, and solubility. Therefore, the thermal study of polymorphism is important to ensure better conditions for synthesis, storage, and transportation of food that contains the myo-inositol. Simultaneous Termogravimetry-Differential Thermal Analysis, Photovisual Differential Scanning Calorimetry, Polarized Light Thermomicroscopy, and Powder X-ray Diffraction were used in investigation. The data show a new thermal event associated to β myo-inositol melting at 221.43°C, suggesting that the solid-solid transition at 185.68°C was incomplete. The kinetics data made it possible to determine the transition lifetime of myo-inositol to occur 5% of solid-solid transition at 20°C and 37°C: 126 and 8years, respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Asymmetric distribution of glucose and indole-3-acetyl-myo-inositol in geostimulated Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Momonoki, Y. S.; Bandurski, R. S. (Principal Investigator)

    1988-01-01

    Indole-3-acetyl-myo-inositol occurs in both the kernel and vegetative shoot of germinating Zea mays seedlings. The effect of a gravitational stimulus on the transport of [3H]-5-indole-3-acetyl-myo-inositol and [U-14C]-D-glucose from the kernel to the seedling shoot was studied. Both labeled glucose and labeled indole-3-acetyl-myo-inositol become asymmetrically distributed in the mesocotyl cortex of the shoot with more radioactivity occurring in the bottom half of a horizontally placed seedling. Asymmetric distribution of [3H]indole-3-acetic acid, derived from the applied [3H]indole-3-acetyl-myo-inositol, occurred more rapidly than distribution of total 3H-radioactivity. These findings demonstrate that the gravitational stimulus can induce an asymmetric distribution of substances being transported from kernel to shoot. They also indicate that, in addition to the transport asymmetry, gravity affects the steady state amount of indole-3-acetic acid derived from indole-3-acetyl-myo-inositol.

  5. One-year effects of myo-inositol supplementation in postmenopausal women with metabolic syndrome.

    PubMed

    Santamaria, A; Giordano, D; Corrado, F; Pintaudi, B; Interdonato, M L; Vieste, G Di; Benedetto, A Di; D'Anna, R

    2012-10-01

    To evaluate the 12-month effect of myo-inositol treatment on some biochemical parameters of women affected by metabolic syndrome. Eighty outpatient postmenopausal women, affected by metabolic syndrome, were enrolled in a 12-month study. All women were treated with a low-energy diet, and then they were randomly assigned to myo-inositol 2 g b.i.d. (n = 40) or placebo (n = 40). All the women were evaluated for serum glucose, insulin, HOMA-IR (Homeostasis Model Assessment-Insulin Resistance), triglycerides, total and high density lipoprotein cholesterol, body mass index (BMI), waist circumference and blood pressure at baseline and after 12 months of treatment. With the exception of BMI and waist circumference, after 12 months of treatment, all the parameters studied showed a significant improvement in the myo-inositol group compared to the control group. At the end of the study, in the myo-inositol group, the number of women without metabolic syndrome was eight (20%) whereas, in the control group, only one woman no longer had the metabolic syndrome after 12 months of diet. Myo-inositol might be considered one of the insulin-sensitizing substances in the treatment of metabolic syndrome.

  6. Dephosphorylation of 1D-myo-inositol 1,4-bisphosphate in rat liver.

    PubMed Central

    Morris, A J; Storey, D J; Downes, C P; Michell, R H

    1988-01-01

    Dephosphorylation of 1D-myo-inositol 1,4-bisphosphate [Ins(1,4)P2] in rat liver is catalysed by a cytosolic phosphatase that removes the 1-phosphate group. The Km for Ins(1,4)P2 is approx. 17 microM. Li+ (100 mM) causes 50% inhibition of Ins(1,4)P2 phosphatase activity when activity is measured at the very low substrate concentration of 10 nM, but on raising the substrate concentration to 100 microM there is a greater than 10-fold increase in sensitivity to Li+, suggesting that Li+ acts mainly, but not entirely, as an uncompetitive inhibitor of Ins(1,4)P2 phosphatase. In addition, rat liver cytosol shows Li+-sensitive phosphatase activity against 1D-myo-inositol 1-,3- and 4-monophosphates. The Ins(1,4)P2 1-phosphatase and inositol monophosphatase activities all share an apparent Mr of 47 x 10(3), as determined by gel-filtration chromatography. However, the Ins(1,4)P2 1-phosphatase is more sensitive to inactivation by heat, and can be separated from inositol monophosphatase activity by anion-exchange chromatography. We conclude that rat liver cytosol contains an Ins(1,4)P2 1-phosphatase that is distinct from, but in many ways similar to, inositol monophosphatase. PMID:2848493

  7. A myo-inositol pool utilized for phosphatidylinositol synthesis is depleted in sciatic nerve from rats with streptozotocin-induced diabetes

    SciTech Connect

    Xi Zhu; Eichberg, J. )

    1990-12-01

    Peripheral nerve from experimentally diabetic rats exhibits lowered levels of myo-inositol (MI) and decreased incorporation of ({sup 3}H)MI into phosphatidylinositol (PI). There are indications that diminished PI turnover may be causally related to reduced Na{sup +}, K{sup +} -ATPase activity in diabetic nerve. The authors have investigated whether a metabolic compartment of MI that is essential for PI synthesis is decreased in this tissue. Sciatic nerve segments form streptozotocin-induced diabetic and age-matched normal rats were incubated in vitro with either {sup 32}P{sub i} or ({sup 3}H)cytidine in the presence of propranolol. This cationic amphiphilic agent redirected nerve phospholipid metabolism to produce enhanced {sup 32}P incorporation into PI and decreased labeling of phosphatidylcholine and phosphatidyl-ethanolamine. The incorporation of ({sup 3}H)cytidine into CMP-PA in normal nerve increased up to 15-fold when 0.6 mM propranolol was present. These results strongly suggest the presence in nerve of a pool of MI that is not in equilibrium with the bulk of nerve MI and that is preferentially used for PI synthesis. This metabolic compartment is depleted in diabetic nerve but can be readily replenished by exogenous MI and may correspond to the MI pool that has been proposed to be required for the turnover of a portion of tissue PI involved in maintenance of normal Na{sup +}, K{sup +} -ATPase activity.

  8. Profiles of lipid components, fatty acid distributions of triacylglycerols and phospholipids in Jack beans (Canavalia gladiata DC.).

    PubMed

    Yoshida, Hiromi; Yoshida, Naoko; Kuriyama, Isoko; Tomiyama-Sakamoto, Yuka; Mizushina, Yoshiyuki

    2013-01-15

    Endogenous tocopherols in extracted lipids from Jack beans (Canavalia gladiata DC.) were determined by high-performance liquid chromatography (HPLC), and were investigated in relation to the fatty acids (FA) distribution of triacylgycerols (TAG) and phospholipids (PL). The dominant tocopherols were (δ)-tocopherol (78.9-96.5mg%) and (γ)-tocopherol (42.1-56.1mg%) with much smaller amounts of (α)-tocopherol (1.1-1.3mg%). The lipids of Jack beans comprised mainly TAG (34.6-38.6 wt.%) and PL (54.8-57.4 wt.%), and other components were also detected in minor proportions (0.3-3.8 wt.%). The PL components included phosphatidyl choline (46.2-48.7 wt.%), phosphatidyl inositol (23.4-29.6 wt.%) and phosphatidyl ethanolamine (18.5-21.2 wt.%). Comparison of these different beans showed, with a few exceptions, no significant differences (P>0.05) in FA distribution. The FA distribution of TAG among the five beans was evident in the Jack beans: unsaturated FA (93.3-95.3 wt.%) were predominantly concentrated at the sn-2 position and saturated FA (33.6-34.4 wt.%) primarily occupying the sn-1 position or sn-3 position. The results obtained from this work would provide useful information to both producers and consumers for manufacturing functional foods or beverages in Japan and elsewhere.

  9. Inositol trisphosphate metabolism in carrot (Daucus carota L. ) cells

    SciTech Connect

    Memon, A.R.; Rincon, M.; Boss, W.F. )

    1989-10-01

    The metabolism of exogenously added D-myo-(1-{sup 3}H)inositol 1,4,5-trisphosphate (IP{sub 3}) has been examined in microsomal membrane and soluble fractions of carrot cells grown in suspension culture. When ({sup 3}H)IP{sub 3} was added to a microsomal membrane fraction, ({sup 3}H)IP{sub 2} was the primary metabolite consisting of approximately 83% of the total recovered ({sup 3}H) by electrophoresis. ({sup 3}H)IP was only 6% of the ({sup 3}H) recovered, and 10% of the ({sup 3}H)IP{sub 3} was not further metabolized. In contrast, when ({sup 3}H)IP{sub 3} was added to the soluble fraction, approximately equal amounts of ({sup 3}H)IP{sub 2} and ({sup 3}H)IP were recovered. Ca{sup 2+} (100 micromolar) tended to enhance IP{sub 3} dephosphorylation but inhibited the IP{sub 2} dephosphorylation in the soluble fraction by about 20%. MoO{sub 4}{sup 2{minus}} (1 millimolar) inhibited the dephosphorylation of IP{sub 3} by the microsomal fraction and the dephosphorylation of IP{sub 2} by the soluble fraction. MoO{sub 4}{sup 2{minus}}, however, did not inhibit the dephosphorylation of IP{sub 3} by the soluble fraction. Li{sup +} (10 and 50 millimolar) had no effect on IP{sub 3} metabolism in either the soluble or membrane fraction; however, Li{sup +} (50 millimolar) inhibited IP{sub 2} dephosphorylation in the soluble fraction about 25%.

  10. Inositol hexaphosphate (IP6) inhibits cellular proliferation in melanoma.

    PubMed

    Rizvi, Irfan; Riggs, Dale R; Jackson, Barbara J; Ng, Alex; Cunningham, Cynthia; McFadden, David W

    2006-06-01

    Inositol Hexaphosphate (IP6) is a naturally occurring polyphosphorylated carbohydrate found in food sources high in fiber content. We have previously reported IP6 to have significant inhibitory effects against pancreatic cancer in vitro. We hypothesized that the IP6 would significantly inhibit cell growth of cutaneous melanoma in vitro. The melanoma line HTB68 was cultured using standard techniques and treated with IP6 at doses ranging from 0.2 to 1.0 mM/well. Cell viability was measured by MTT at 72 h. VEGF production was measured in the cell supernatants by ELISA. Apoptosis was evaluated by Annexin V-FITC and results calculated using FACS analysis. Statistical analysis was performed by ANOVA. Significant reductions (P < 0.001) in cellular proliferation were observed with IP6. Overall, IP6 exhibited a mean inhibition of cell growth of 52.1 +/- 11.5% (range, 1.6-83.0%) at 72 h of incubation. VEGF production was significantly reduced (P < 0.001) by the addition of IP6 (7.5 pg/ml) compared to control (40.9 pg/ml). IP6 significantly increased (P = 0.029) late apoptosis from 5.3 to 7.0% gated events. No changes in necrosis or early apoptosis were observed. Adjuvant treatment of melanoma continues to challenge clinicians and patients. Our findings that IP6 significantly decreased cellular growth, VEGF production and increased late apoptosis in melanoma suggest its potential therapeutic value. Further in vivo studies are planned to evaluate safety and clinical utility of this agent.

  11. Anti-angiogenic activity of inositol hexaphosphate (IP6).

    PubMed

    Vucenik, Ivana; Passaniti, Antonino; Vitolo, Michele I; Tantivejkul, Kwanchanit; Eggleton, Paul; Shamsuddin, Abulkalam M

    2004-11-01

    A significant anticancer activity of the naturally occurring carbohydrate inositol hexaphosphate (IP(6)) has been reported against numerous cancer models. Since tumors require angiogenesis for growth and metastasis, we hypothesize that IP(6) reduces tumor growth by inhibiting angiogenesis. Because angiogenesis depends on the interaction between endothelial and tumor cells, we investigated the effect of IP(6) on both. IP(6) inhibited the proliferation and induced the differentiation of endothelial cells in vitro; the growth of bovine aortic endothelial cells (BAECs) evaluated by MTT proliferation assay was inhibited in a dose-dependent manner (IC(50) = 0.74 mM). The combination of IP(6) and vasostatin, a calreticulin fragment with anti-angiogenic activity, was synergistically superior in growth inhibition than either compound. IP(6) inhibited human umbilical vein endothelial cell (HUVEC) tube formation (in vitro capillary differentiation) on a reconstituted extracellular matrix, Matrigel, and disrupted pre-formed tubes. IP(6) significantly reduced basic fibroblast growth factor (bFGF)-induced vessel formation (P < 0.01) in vivo in Matrigel plug assay. Exposure of HepG2, a human hepatoma cell line, to IP(6) for 8 h, resulted in a dose-dependent decrease in the mRNA levels of vascular endothelial growth factor (VEGF), as assessed by RT-PCR. IP(6) treatment of HepG2 cells for 24 h also significantly reduced the VEGF protein levels in conditioned medium, in a concentration-dependent manner (P = 0.012). Thus, IP(6) has an inhibitory effect on induced angiogenesis.

  12. Relative quantification of phospholipid accumulation in the PC12 cell plasma membrane following phospholipid incubation using TOF-SIMS imaging

    PubMed Central

    Lanekoff, Ingela; Sjövall, Peter; Ewing, Andrew G.

    2011-01-01

    Time of flight secondary ion mass spectrometry (TOF-SIMS) imaging has been used to investigate the incorporation of phospholipids into the plasma membrane of PC12 cells after incubation with phosphatidylcholine (PC) and phosphatidylethanolamine (PE). The incubations were done at concentrations previously shown to change the rate of exocytosis in model cell lines. The use of TOF-SIMS in combination with an in situ freeze fracture device enables the acquisition of ion images from the plasma membrane in single PC12 cells. By incubating cells with deuterated phospholipids and acquiring ion images at high mass resolution, specific deuterated fragment ions were used to monitor the incorporation of lipids into the plasma membrane. The concentration of incorporated phospholipids relative to the original concentration of PC was thus determined. The observed relative amounts of phospholipid accumulation in the membrane ranges from 0.5 to 2 percent following 19 hours of incubation with PC at 100 to 300 μM and from 1 to 9 percent following incubation with PE at the same concentrations. Phospholipid accumulation is therefore shown to be dependent on the concentration in the surrounding media. In combination with previous exocytosis results, the present data suggests that very small changes in the plasma membrane phospholipid concentration are sufficient to produce significant effects on important cellular processes, such as exocytosis in PC12 cells. PMID:21563801

  13. Diabetes-induced increases in vascular permeability and changes in granulation tissue levels of sorbitol, myo-inositol, chiro-inositol, and scyllo-inositol are prevented by sorbinil.

    PubMed

    Williamson, J R; Chang, K; Rowold, E; Marvel, J; Tomlinson, M; Sherman, W R; Ackermann, K E; Kilo, C

    1986-04-01

    In a recently developed animal model, we investigated the pathogenesis of diabetic vascular disease and demonstrated that 125I-albumin permeation is markedly increased in new "granulation tissue" vessels formed in subcutaneous tissue after the onset of diabetes. The studies described in this report were undertaken to examine the effects of an aldose reductase inhibitor on diabetes-induced increases in vascular permeability in this animal model. 125I-albumin permeation was assessed 3 weeks after the subcutaneous implantation of sterile preweighed polyester fabric (to stimulate angiogenesis) in diabetic male Sprague-Dawley rats, in controls, and in diabetic rats given sorbinil approximately 12 or approximately 25 mg/kg/d mixed in ground rat chow. Sorbinil administration prevented the diabetes-induced increase in vascular permeability by approximately 60% at the lower dose and by approximately 80% at the higher dose without affecting body weight or plasma glucose levels. Diabetes-induced changes in tissue levels of sorbitol, myo-inositol, scyllo-inositol, and chiro-inositol were also prevented by the high dose of sorbinil (data were not obtained for the lower dose). These observations are consistent with evidence linking diabetic cataracts and neuropathy to imbalances in sorbitol/inositol metabolism and support the hypothesis that diabetic vascular disease as well as neuropathy and cataracts are mediated by excess metabolism of glucose through the polyol pathway. Furthermore, these observations suggest that increased vascular permeability associated with diabetic microangiopathy in humans may be prevented by inhibitors of aldose reductase without the need to normalize blood glucose levels.

  14. Planning School-Based Sexuality Programs Utilizing the PRECEDE Model.

    ERIC Educational Resources Information Center

    Rubinson, Laurna; Baillie, Lorraine

    1981-01-01

    The epidemic status of teenage pregnancy, venereal disease, and rape has resulted in increased responsibilities for schools in providing human sexuality education. The PRECEDE model provides an assessment of social factors and an investigation of the behavioral causes as identified by the community. (JN)

  15. 48 CFR 3452.215-33 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Order of precedence. 3452.215-33 Section 3452.215-33 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and...

  16. Impact of preceding crop on alfalfa competitiveness with weeds

    USDA-ARS?s Scientific Manuscript database

    Organic producers would like to include no-till practices in their farming systems. We are seeking to develop a continuous no-till system for organic farming, based on a complex rotation that includes a 3-year sequence of alfalfa. In this study, we evaluated impact of preceding crop on weed infest...

  17. Independence Pending: Teacher Behaviors Preceding Learner Problem Solving

    ERIC Educational Resources Information Center

    Roesler, Rebecca A.

    2017-01-01

    The purposes of the present study were to identify the teacher behaviors that preceded learners' active participation in solving musical and technical problems and describe learners' roles in the problem-solving process. I applied an original model of problem solving to describe the behaviors of teachers and students in 161 rehearsal frames…

  18. Alfalfa suppression of weeds is affected by preceding crop

    USDA-ARS?s Scientific Manuscript database

    Organic producers are seeking alternative tactics for weed control so that they can reduce their need for tillage. In this study, we examined the impact of the preceding crop on alfalfa suppression of weeds. Alfalfa was most competitive with weeds following soybean. When following spring wheat, v...

  19. 32 CFR 300.2 - DLA FOIA regulatory precedence.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 2 2014-07-01 2014-07-01 false DLA FOIA regulatory precedence. 300.2 Section 300.2 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) FREEDOM OF INFORMATION ACT PROGRAM DEFENSE LOGISTICS AGENCY FREEDOM OF INFORMATION ACT PROGRAM General...

  20. Therapist activities preceding setbacks in the assimilation process.

    PubMed

    Gabalda, Isabel Caro; Stiles, William B; Pérez Ruiz, Sergio

    2016-11-01

    This study examined the therapist activities immediately preceding assimilation setbacks in the treatment of a good-outcome client treated with linguistic therapy of evaluation (LTE). Setbacks (N = 105) were defined as decreases of one or more assimilation stages from one passage to the next dealing with the same theme. The therapist activities immediately preceding those setbacks were classified using two kinds of codes: (a) therapist interventions and (b) positions the therapist took toward the client's internal voices. Preceding setbacks to early assimilation stages, where the problem was unformulated, the therapist was more often actively listening, and the setbacks were more often attributable to pushing a theme beyond the client's working zone. Preceding setbacks to later assimilation stages, where the problem was at least formulated, the therapist was more likely to be directing clients to consider alternatives, following the LTE agenda, and setbacks were more often attributable to the client following these directives shifting attention to less assimilated (but nevertheless formulated) aspects of the problem. At least in this case, setbacks followed systematically different therapist activities depending on the problem's stage of assimilation. Possible implications for the assimilation model's account of setbacks and for practice are discussed.

  1. Metrical expectations from preceding prosody influence perception of lexical stress

    PubMed Central

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C.; Tanenhaus, Michael K.

    2015-01-01

    Two visual-world experiments tested the hypothesis that expectations based on preceding prosody influence the perception of suprasegmental cues to lexical stress. The results demonstrate that listeners’ consideration of competing alternatives with different stress patterns (e.g., ‘jury/gi’raffe) can be influenced by the fundamental frequency and syllable timing patterns across material preceding a target word. When preceding stressed syllables distal to the target word shared pitch and timing characteristics with the first syllable of the target word, pictures of alternatives with primary lexical stress on the first syllable (e.g., jury) initially attracted more looks than alternatives with unstressed initial syllables (e.g., giraffe). This effect was modulated when preceding unstressed syllables had pitch and timing characteristics similar to the initial syllable of the target word, with more looks to alternatives with unstressed initial syllables (e.g., giraffe) than to those with stressed initial syllables (e.g., jury). These findings suggest that expectations about the acoustic realization of upcoming speech include information about metrical organization and lexical stress, and that these expectations constrain the initial interpretation of suprasegmental stress cues. These distal prosody effects implicate on-line probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. PMID:25621583

  2. Cross-frequency interactions in the precedence effect.

    PubMed

    Shinn-Cunningham, B G; Zurek, P M; Durlach, N I; Clifton, R K

    1995-07-01

    This paper concerns the extent to which the precedence effect is observed when leading and lagging sounds occupy different spectral regions. Subjects, listening under headphones, were asked to match the intracranial lateral position of an acoustic pointer to that of a test stimulus composed of two binaural noise bursts with asynchronous onsets, parametrically varied frequency content, and different interaural delays. The precedence effect was measured by the degree to which the interaural delay of the matching pointer was independent of the interaural delay of the lagging noise burst in the test stimulus. The results, like those of Blauert and Divenyi [Acustica 66, 267-274 (1988)], show an asymmetric frequency effect in which the lateralization influence of a lagging high-frequency burst is almost completely suppressed by a leading low-frequency burst, whereas a lagging low-frequency burst is weighted equally with a leading high-frequency burst. This asymmetry is shown to be the result of an inherent low-frequency dominance that is seen even with simultaneous bursts. When this dominance is removed (by attenuating the low-frequency burst) the precedence effect operates with roughly equal strength both upward and downward in frequency. Within the scope of the current study (with lateralization achieved through the use of interaural time differences alone, stimuli from only two frequency bands, and only three subjects performing in all experiments), these results suggest that the precedence effect arises from a fairly central processing stage in which information is combined across frequency.

  3. A Precedent for Test Validation. ERIC/TM Digest.

    ERIC Educational Resources Information Center

    Rudner, Lawrence; Farris, Michael P.

    In December 1991, the South Carolina Supreme Court ordered the State Board of Education to stop using the Education Entrance Examination (EEE) for licensing parents who want to teach their children at home. In ruling that the test's validation process did not meet a standard of reasonableness, the Court established a significant precedent for test…

  4. Independence Pending: Teacher Behaviors Preceding Learner Problem Solving

    ERIC Educational Resources Information Center

    Roesler, Rebecca A.

    2017-01-01

    The purposes of the present study were to identify the teacher behaviors that preceded learners' active participation in solving musical and technical problems and describe learners' roles in the problem-solving process. I applied an original model of problem solving to describe the behaviors of teachers and students in 161 rehearsal frames…