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Sample records for inositol phospholipids precedes

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

    PubMed Central

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

    2014-01-01

    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. PMID:25180230

  2. Inositol Depletion Restores Vesicle Transport in Yeast Phospholipid Flippase Mutants

    PubMed Central

    Yamagami, Kanako; Yamamoto, Takaharu; Sakai, Shota; Mioka, Tetsuo; Sano, Takamitsu; Igarashi, Yasuyuki; Tanaka, Kazuma

    2015-01-01

    In eukaryotic cells, type 4 P-type ATPases function as phospholipid flippases, which translocate phospholipids from the exoplasmic leaflet to the cytoplasmic leaflet of the lipid bilayer. Flippases function in the formation of transport vesicles, but the mechanism remains unknown. Here, we isolate an arrestin-related trafficking adaptor, ART5, as a multicopy suppressor of the growth and endocytic recycling defects of flippase mutants in budding yeast. Consistent with a previous report that Art5p downregulates the inositol transporter Itr1p by endocytosis, we found that flippase mutations were also suppressed by the disruption of ITR1, as well as by depletion of inositol from the culture medium. Interestingly, inositol depletion suppressed the defects in all five flippase mutants. Inositol depletion also partially restored the formation of secretory vesicles in a flippase mutant. Inositol depletion caused changes in lipid composition, including a decrease in phosphatidylinositol and an increase in phosphatidylserine. A reduction in phosphatidylinositol levels caused by partially depleting the phosphatidylinositol synthase Pis1p also suppressed a flippase mutation. These results suggest that inositol depletion changes the lipid composition of the endosomal/TGN membranes, which results in vesicle formation from these membranes in the absence of flippases. PMID:25781026

  3. myo-Inositol uptake is essential for bulk inositol phospholipid but not glycosylphosphatidylinositol synthesis in Trypanosoma brucei.

    PubMed

    Gonzalez-Salgado, Amaia; Steinmann, Michael E; Greganova, Eva; Rauch, Monika; Mäser, Pascal; Sigel, Erwin; Bütikofer, Peter

    2012-04-13

    myo-Inositol is an essential precursor for the production of inositol phosphates and inositol phospholipids in all eukaryotes. Intracellular myo-inositol is generated by de novo synthesis from glucose 6-phosphate or is provided from the environment via myo-inositol symporters. We show that in Trypanosoma brucei, the causative pathogen of human African sleeping sickness and nagana in domestic animals, myo-inositol is taken up via a specific proton-coupled electrogenic symport and that this transport is essential for parasite survival in culture. Down-regulation of the myo-inositol transporter using RNA interference inhibited uptake of myo-inositol and blocked the synthesis of the myo-inositol-containing phospholipids, phosphatidylinositol and inositol phosphorylceramide; in contrast, it had no effect on glycosylphosphatidylinositol production. This together with the unexpected localization of the myo-inositol transporter in both the plasma membrane and the Golgi demonstrate that metabolism of endogenous and exogenous myo-inositol in T. brucei is strictly segregated. PMID:22351763

  4. Effects of tachykinins on inositol phospholipid hydrolysis in slices of hamster urinary bladder.

    PubMed Central

    Bristow, D. R.; Curtis, N. R.; Suman-Chauhan, N.; Watling, K. J.; Williams, B. J.

    1987-01-01

    Tachykinin-stimulated inositol phospholipid hydrolysis was examined in slices of hamster urinary bladder. In the presence of lithium, to inhibit inositol monophosphatase activity, substance P, eledoisin and related tachykinins induced large, dose-dependent increases in [3H]-inositol monophosphate accumulation. The responses to substance P and eledoisin were not antagonized by the cholinoceptor antagonist, atropine. The rank order of potency for various tachykinins was kassinin greater than neurokinin A greater than neurokinin B greater than eledoisin greater than physaelamin greater than substance P greater than substance P methyl ester. The synthetic analogue [p-Glu6, D-Pro9]SP (6-11) was considerably more potent than its L-prolyl stereoisomer at stimulating inositol phospholipid hydrolysis. These results suggest that in the hamster urinary bladder, tachykinin-induced inositol phospholipid breakdown is mediated via tachykinin receptors of the SP-E type, as opposed to the SP-P type. PMID:3028559

  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. Inositol phospholipid hydrolysis in cultured astrocytes and oligodendrocytes

    SciTech Connect

    Ritchie, T.; Cole, R.; Kim, H.S.; de Vellis, J.; Noble, E.P.

    1987-07-06

    Cultures of astrocytes and oligodendrocytes were prelabeled with /sup 3/H-inositol and the accumulation of /sup 3/H-inositol phosphates was determined following stimulation with a number of neuroactive substances. In astrocytes, norepinephrine (NE) produced the greatest stimulation with significant increase also observed with bradykinin. In oligodendrocytes, the greatest stimulation was produced by carbachol with significant increase also produced by bradykinin, histamine and NE. Carbachol was found to be ineffective in producing stimulation in astrocytes. The accumulation of /sup 3/H-inositol phosphates in astrocytes in response to NE was found to be dependent on the presence of Li/sup +/. The NE stimulation in astrocytes was dose-dependent and had an EC/sub 50/ of 1.2 ..mu..M. This stimulation was blocked by the low concentration of the ..cap alpha../sub 1/-adrenergic antagonist prazosin but not by the ..cap alpha../sub 2/-adrenergic antagonist yohimbine. The NE-stimulated accumulation of /sup 3/H-inositol phosphates in astrocytes was inhibited by the cyclic nucleotide phosphodiesterase inhibitor isobutylmethylxanthine as well as by the cAMP analog dibutyryl cAMP. 34 references, 4 figures, 4 tables.

  8. Depletion of arachidonic acid from GH3 cells. Effects on inositol phospholipid turnover and cellular activation.

    PubMed Central

    Dudley, D T; Macfarlane, D E; Spector, A A

    1987-01-01

    We have adapted rat pituitary GH3 cells to grow in delipidated culture medium. In response, esterfied linoleic acid and arachidonic acid become essentially undetectable, whereas eicosa-5,8,11-trienoic acid accumulates and oleic acid increases markedly. These changes occur in all phospholipid classes, but are particularly pronounced in inositol phospholipids, where the usual stearate/arachidonate profile is replaced with oleate/eicosatrienoate (n - 9) and stearate/eicosatrienoate (n - 9). Incubation of arachidonate-depleted cells with 10 microM-arachidonic acid for only 24 h results in extensive remodelling of phospholipid fatty acids, such that close-to-normal compositions and arachidonic acid content are achieved for the inositol phospholipids. In comparison studies with arachidonic acid-depleted or -repleted cells, it was found that the arachidonate content does not affect thyrotropin-releasing-hormone (TRH)-stimulated responses measured at long time points, including [32P]Pi labelling of phosphatidylinositol and phosphatidic acid, stimulation of protein phosphorylation, and basal or TRH-stimulated prolactin release. However, transient events such as stimulated breakdown of inositol phospholipids and an initial rise in diacylglycerol are enhanced by the presence of arachidonate. These results show that arachidonic acid itself is not required for operation of the phosphatidylinositol cycle and is not an obligatory intermediate in TRH-mediated GH3 cell activation. It is possible that any structural or functional role of arachidonic acid in these processes is largely met by replacement with eicosatrienoate (n - 9). However, since arachidonate in inositol phospholipids facilitates their hydrolysis upon stimulation by TRH, arachidonic acid apparently may have a specific role in the recognition of these lipids by phospholipase C. Images Fig. 4. PMID:3120699

  9. 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.

  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. 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.

  12. 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

  13. Agonist-induced desensitization of histamine H1 receptor-mediated inositol phospholipid hydrolysis in human umbilical vein endothelial cells.

    PubMed Central

    McCreath, G; Hall, I P; Hill, S J

    1994-01-01

    1. The regulation of histamine-induced [3H]-inositol phosphate formation was studied in human cultured umbilical vein endothelial cells (HUVEC). 2. Histamine (EC50 4.8 microM) produced a 12.7 fold increase in [3H]-inositol phosphate formation over basal levels. Prior exposure to 0.1 mM histamine (2 h) produced a 78% reduction in the response to subsequent histamine (0.1 mM) challenge. The IC50 for this histamine-induced desensitization was 0.9 microM. 3. The inositol phosphate response to histamine (0.1 mM) was inhibited by phorbol dibutyrate (IC50 40 nM; maximal reduction 64%). This effect was antagonized by both staurosporine (100 nM) and Ro 31-8220 (10 microM). However, the histamine-induced desensitization of the H1-receptor-mediated inositol phosphate response was insensitive to the protein kinase inhibitors, staurosporine, Ro 31-8220, K252a and KN62. 4. Prior exposure to sodium nitroprusside (100 microM), forskolin (10 microM) or dibutyryl cyclic AMP (1 mM) had no effect upon histamine-induced [3H]-inositol phosphate formation. 5. NaF (20 mM) and thrombin (EC50 0.4 u ml-1) also induced inositol phosphate formation in HUVEC. Histamine pretreatment (0.1 mM, 10-120 min) failed to modify the inositol phosphate response to a subsequent NaF or thrombin challenge. 6. We conclude that the desensitization of histamine H1-receptor-mediated [3H]-inositol phosphate formation occurs at the level of the receptor and involves a mechanism independent of activation of protein kinase A, G, or C, or calcium calmodulin-dependent protein kinase II. PMID:7858873

  14. Molecular Characterization of an Arabidopsis Gene Encoding a Phospholipid-Specific Inositol Polyphosphate 5-Phosphatase1[w

    PubMed Central

    Ercetin, Mustafa E.; Gillaspy, Glenda E.

    2004-01-01

    Phosphoinositides are important molecules that serve as second messengers and bind to a complex array of proteins modulating their subcellular location and activity. The enzymes that metabolize phosphoinositides can in some cases serve to terminate the signaling actions of phosphoinositides. The inositol polyphosphate 5-phosphatases (5PTases) comprise a large protein family that hydrolyzes 5-phosphates from a variety of inositol phosphate and phosphoinositide substrates. We previously reported the identification of 15 putative 5PTase genes in Arabidopsis and have shown that overexpression of the At5PTase1 gene can alter abscisic acid signaling. At5PTase1 and At5PTase2 have been shown to hydrolyze the 5-phosphate from inositol phosphate substrates. We have examined the substrate specificity of the At5PTase11 protein, which is one of the smallest predicted 5PTases found in any organism. We report here that the At5PTase11 gene encodes an active 5PTase enzyme that can only dephosphorylate phosphoinositide substrates containing a 5-phosphate. In addition to hydrolyzing known substrates of 5PTase enzymes, At5PTase11 also hydrolyzes the 5-phosphate from phosphatidylinositol (3,5) bisphosphate. We also show that the At5PTase11 gene is regulated by abscisic acid, jasmonic acid, and auxin, suggesting a role for phosphoinositide action in these signal transduction pathways. PMID:15181205

  15. 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.

  16. 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.

  17. 12(S)-hydroxyeicosatetraenoic acid and 13(S)-hydroxyoctadecadienoic acid regulation of protein kinase C-alpha in melanoma cells: role of receptor-mediated hydrolysis of inositol phospholipids.

    PubMed Central

    Liu, B; Khan, W A; Hannun, Y A; Timar, J; Taylor, J D; Lundy, S; Butovich, I; Honn, K V

    1995-01-01

    Protein kinase C (PKC) isoenzymes are essential components of cell signaling. In this study, we investigated the regulation of PKC-alpha in murine B16 amelanotic melanoma (B16a) cells by the monohydroxy fatty acids 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] and 13(S)-hydroxyoctadecadienoic acid [13(S)-HODE]. 12(S)-HETE induced a translocation of PKC-alpha to the plasma membrane and focal adhesion plaques, leading to enhanced adhesion of B16a cells to the matrix protein fibronectin. However, 13(S)-HODE inhibited these 12(S)-HETE effects on PKC-alpha. A receptor-mediated mechanism of action for 12(S)-HETE and 13(S)-HODE is supported by the following findings. First, 12(S)-HETE triggered a rapid increase in cellular levels of diacylglycerol and inositol trisphosphate in B16a cells. 13(S)-HODE blocked the 12(S)-HETE-induced bursts of both second messengers. Second, the 12(S)-HETE-increased adhesion of B16a cells to fibronectin was sensitive to inhibition by a phospholipase C inhibitor and pertussis toxin. Finally, a high-affinity binding site (Kd = 1 nM) for 12(S)-HETE was detected in B16a cells, and binding of 12(S)-HETE to B16a cells was effectively inhibited by 13(S)-HODE (IC50 = 4 nM). In summary, our data provide evidence that regulation of PKC-alpha by 12(S)-HETE and 13(S)-HODE may be through a guanine nucleotide-binding protein-linked receptor-mediated hydrolysis of inositol phospholipids. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7568126

  18. 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.

  19. Phosphate, inositol and polyphosphates.

    PubMed

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

    2016-02-15

    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. PMID:26862212

  20. Inositol-Requiring Mutants of SACCHAROMYCES CEREVISIAE

    PubMed Central

    Culbertson, Michael R.; Henry, Susan A.

    1975-01-01

    Fifty-two inositol-requiring mutants of Saccharomyces cerevisiae were isolated following mutagenesis with ethyl methanesulfonate. Complementation and tetrad analysis revealed ten major complementation classes, representing ten independently segregating loci (designated ino1 through ino10) which recombined freely with their respective centromeres. Members of any given complementation class segregated as alleles of a single locus. Thirteen complementation subclasses were identified among thirty-six mutants which behaved as alleles of the ino1 locus. The complementation map for these mutants was circular.—Dramatic cell viability losses indicative of unbalanced growth were observed in liquid cultures of representative mutants under conditions of inositol starvation. Investigation of the timing, kinetics, and extent of cell death revealed that losses in cell viability in the range of 2-4 log orders could be prevented by the addition of inositol to the medium or by disruption of protein synthesis with cycloheximide. Mutants defective in nine of the ten loci identified in this study displayed these unusual characteristics. The results suggest an important physiological role for inositol that may be related to its cellular localization and function in membrane phospholipids. The possibility is discussed that inositol deficiency initiates the process of unbalanced growth leading to cell death through the loss of normal assembly, function, or integrity of biomembranes.—Part of this work has been reported in preliminary form (Culbertson and Henry 1974). PMID:1093935

  1. 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.

  2. Inositol pyrophosphate pyrotechnics.

    PubMed

    Bhandari, Rashna; Chakraborty, Anutosh; Snyder, Solomon H

    2007-05-01

    Physiologic roles of highly phosphorylated inositol phosphates, including those containing pyrophosphate groups, have been the focus of much recent interest. In the April 6, 2007 issue of Science, two papers (Lee et al., 2007; Mulugu et al., 2007) demonstrate the occurrence of a novel inositol pyrophosphate molecule in yeast and elucidate its role in phosphate homeostasis. PMID:17488633

  3. RETROGRADE AXONAL TRANSPORT OF PHOSPHOINOSITIDES AFTER INTRANEURAL INJECTION OF [3H]MYO-INOSITOL INTO THE RAT SCIATIC NERVE

    EPA Science Inventory

    Although autoradiography has demonstrated local incorporation of [3H]inositol into axonal phospholipids after intraneural injection (Gould, 1976; Gould et at., 1987b), retrograde axonal transport of phosphatidylinositol has only been demonstrated after injection of lipid precurso...

  4. 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.

  5. 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. PMID:25888554

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

    PubMed Central

    González-Salgado, Amaia; Steinmann, Michael; Major, Louise L.; Sigel, Erwin; Reymond, Jean-Louis

    2015-01-01

    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. PMID:25888554

  7. Phospholipid Scramblases

    PubMed Central

    Williamson, Patrick

    2015-01-01

    The distribution of phospholipid types between the two leaflets of a membrane bilayer is a controlled feature of membrane structure. One of the two membrane catalytic activities governing this distribution randomizes the composition of the two leaflets—the phospholipid scramblases. Two proteins (Xkr8 and TMEM16F) required for the activation of these activities have been identified. One of these proteins (TMEM16F) is quite clearly a scramblase itself and provides insight into the mechanism by which transbilayer phospholipid movement is facilitated. PMID:26843813

  8. 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

  9. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  11. Preparation of quality inositol pyrophosphates.

    PubMed

    Loss, Omar; Azevedo, Cristina; Szijgyarto, Zsolt; Bosch, Daniel; Saiardi, Adolfo

    2011-01-01

    Myo-inositol is present in nature either unmodified or in more complex phosphorylated derivates. Of the latest, the two most abundant in eukaryotic cells are inositol pentakisphosphate (IP(5;)) and inositol hexakisphosphate (phytic acid or IP(6;)). IP(5;) and IP(6;) are the precursors of inositol pyrophosphate molecules that contain one or more pyrophosphate bonds(1). Phosphorylation of IP(6;) generates diphoshoinositolpentakisphosphate (IP(7;) or PP-IP(5;)) and bisdiphoshoinositoltetrakisphosphate (IP(8;) or (PP)(2;)-IP(4;)). Inositol pyrophosphates have been isolated from all eukaryotic organisms so far studied. In addition, the two distinct classes of enzymes responsible for inositol pyrophosphate synthesis are highly conserved throughout evolution(2-4). The IP(6;) kinases (IP(6;)Ks) posses an enormous catalytic flexibility, converting IP(5;) and IP(6;) to PP-IP(4;) and IP(7;) respectively and subsequently, by using these products as substrates, promote the generation of more complex molecules(5,6). Recently, a second class of pyrophosphate generating enzymes was identified in the form of the yeast protein VIP(1;) (also referred as PP-IP(5;)K), which is able to convert IP(6;) to IP(7;) and IP(8;)(7,8). Inositol pyrophosphates regulate many disparate cellular processes such as insulin secretion(9), telomere length(10,11), chemotaxis(12), vesicular trafficking(13), phosphate homeostasis(14) and HIV-1 gag release(15). Two mechanisms of actions have been proposed for this class of molecules. They can affect cellular function by allosterically interacting with specific proteins like AKT(16). Alternatively, the pyrophosphate group can donate a phosphate to pre-phosphorylated proteins(17). The enormous potential of this research field is hampered by the absence of a commercial source of inositol pyrophosphates, which is preventing many scientists from studying these molecules and this new post-translational modification. The methods currently available to isolate

  12. 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.

  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. Myo-inositol transport in Saccharomyces cerevisiae.

    PubMed

    Nikawa, J; Nagumo, T; Yamashita, S

    1982-05-01

    myo-Inositol uptake in Saccharomyces cerevisiae was dependent on temperature, time, and substrate concentration. The transport obeyed saturation kinetics with an apparent Km for myo-inositol of 0.1 mM, myo-Inositol analogs, such as scyllo-inositol, 2-inosose, mannitol, and 1,2-cyclohexanediol, had no effect on myo-inositol uptake, myo-Inositol uptake required metabolic energy. Removal of D-glucose resulted in a loss of activity, and azide and cyanide ions were inhibitory. In the presence of D-glucose, myo-inositol was accumulated in the cells against a concentration gradient. A myo-inositol transport mutant was isolated from UV-mutagenized S. cerevisiae cells using the replica-printing technique. The defect in myo-inositol uptake was due to a single nuclear gene mutation. The activities of L-serine and D-glucose transport were not affected by the mutation. Thus it was shown that S. cerevisiae grown under the present culture conditions possessed a single and specific myo-inositol transport system. myo-Inositol transport activity was reduced by the addition of myo-inositol to the culture medium. The activity was reversibly restored by the removal of myo-inositol from the medium. This restoration of activity was completely abolished by cycloheximide. PMID:7040334

  15. 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

    2016-03-01

    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. PMID:26854536

  16. 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

  17. 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 § 582.5370 Inositol. (a) Product. Inositol....

  18. 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.

  19. Phospholipid transport via mitochondria

    PubMed Central

    Tamura, Yasushi; Sesaki, Hiromi; Endo, Toshiya

    2014-01-01

    In eukaryotic cells, complex membrane structures called organelles are highly developed to exert specialized functions. Mitochondria are one of such organelles consisting of the outer and inner membranes with characteristic protein and phospholipid compositions. Maintaining proper phospholipid compositions of the membranes is crucial for mitochondrial integrity, thereby contributing to normal cell activities. Since cellular locations for phospholipid synthesis are restricted to specific compartments such as the endoplasmic reticulum (ER) membrane and the mitochondrial inner membrane, newly synthesized phospholipids have to be transported and distributed properly from the ER or mitochondria to other cellular membranes. Although understanding of molecular mechanisms of phospholipid transport are much behind those of protein transport, recent studies using yeast as a model system began to provide intriguing insights into phospholipid exchange between the ER and mitochondria as well as between the mitochondrial outer and inner membranes. In this review, we summarize the latest findings of phospholipid transport via mitochondria and discuss the implicated molecular mechanisms. PMID:24954234

  20. Measurement of phospholipase C by monitoring inositol phosphates using [³H]inositol labeling protocols in permeabilized cells.

    PubMed

    Skippen, Alison; Swigart, Philip; Cockcroft, Shamshad

    2013-01-01

    Data on the production of inositol phosphates is a useful complement to measurements of intracellular Ca(2+). The basic principle is labeling of the inositol lipids by growing the appropriate cell line in culture in the presence of [3H]inositol for 2-3 days to reach labeling equilibrium. Lithium ions at 10 mM inhibits the degradation of inositol phosphates to free inositol and is used to trap the inositol in the inositol polyphosphate forms. Inositol phosphates can be separated with ease from free inositol by using anion exchange chromatography. A method capable of easily processing approximately 40-60 samples in a single day is presented. PMID:23007585

  1. 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.

  2. 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.

  3. Osmoregulation of Na(+)-inositol cotransporter activity and mRNA levels in brain glial cells.

    PubMed

    Paredes, A; McManus, M; Kwon, H M; Strange, K

    1992-12-01

    During plasma hypertonicity brain volume is regulated acutely by electrolyte uptake and chronically by accumulation of organic solutes such as inositol. Cultured rat C6 glioma cells, an astrocyte-like cell line, show a similar pattern of volume control. Volume regulatory accumulation of inositol requires external inositol, indicating that membrane transport plays a central role in this process. The inositol uptake pathway is Na+ dependent and exhibits Michaelis-Menten kinetics. Chronic hypertonic acclimation results in a twofold increase in the maximum velocity of the transporter without changing the Km. Hypertonic stress also results in a 17-fold increase in transporter mRNA. Elevation of mRNA levels precedes activation of the transporter by 4-6 h, suggesting that increased inositol uptake is mediated by synthesis and membrane insertion of new transport proteins. Reacclimation of hypertonic cells to isotonicity causes a rapid reduction of transporter mRNA levels to control levels within 4 h. In contrast, downregulation of transport activity does not begin until between 10 and 24 h after reexposure to isotonicity. PMID:1476169

  4. Metabolic evidence for the order of addition of individual phosphate esters in the myo-inositol moiety of inositol hexakisphosphate in the duckweed Spirodela polyrhiza L.

    PubMed Central

    Brearley, C A; Hanke, D E

    1996-01-01

    The aquatic monocotyledonous plant Spirodela polyrhiza was labelled with [33P]Pi for short periods under non-equilibrium conditions. An InsP6 fraction was obtained and dissected by using enantiospecific (enzymic) and non-enantiospecific (chemical) means to determine the relative labelling of individual phosphate substituents on the inositol ring of InsP6. Phosphates in positions D-1, -2, -3, -4, -5 and -6 contained approx. 21%, 32-39%, 9-10%, 14-16%, 19-23% and 16-18% of the label respectively. We conclude from the foregoing, together with identities [described in the preceding paper, Brearley and Hanke (1996) Biochem. J. 314, 215-225] of inositol phosphates found in this plant at a developmental stage associated with massive accumulation of InsP6, that synthesis of InsP6 from myo-inositol proceeds according to the sequence Ins3P-->Ins(3,4)P2-->Ins(3,4,6)P3-->Ins(3,4,5,6)P4-->Ins(1,3,4,5,6 ) P5-->InsP6 in Spirodela polyrhiza. These results represent the first description of the synthetic sequence to InsP6 in the plant kingdom and the only comprehensive description of endogenous inositol phosphates in any plant tissue. The sequence described differs from that reported in the slime mould Dictyostelium discoideum. PMID:8660287

  5. How versatile are inositol phosphate kinases?

    PubMed Central

    Shears, Stephen B

    2004-01-01

    This review assesses the extent and the significance of catalytic versatility shown by several inositol phosphate kinases: the inositol phosphate multikinase, the reversible Ins(1,3,4) P (3)/Ins(3,4,5,6) P (4) kinase, and the kinases that synthesize diphosphoinositol polyphosphates. Particular emphasis is placed upon data that are relevant to the situation in vivo. It will be shown that catalytic promiscuity towards different inositol phosphates is not typically an evolutionary compromise, but instead is sometimes exploited to facilitate tight regulation of physiological processes. This multifunctionality can add to the complexity with which inositol signalling pathways interact. This review also assesses some proposed additional functions for the catalytic domains, including transcriptional regulation, protein kinase activity and control by molecular 'switching', all in the context of growing interest in 'moonlighting' (gene-sharing) proteins. PMID:14567754

  6. Phospholipid biosynthesis in the oyster protozoan parasite, Perkinsus marinus.

    PubMed

    Lund, Eric D; Chu, Fu-Lin E

    2002-05-01

    Perkinsus marinus is a protozoan parasite that causes high mortality in its commercially and ecologically important host, the Eastern oyster Crassostrea virginica. In order to understand the host-parasite relationship in lipid metabolism, the ability of P. marinus to synthesize phospholipids from polar headgroup precursors was investigated. Pulse/chase experiments were conducted using radiolabled serine, choline, ethanolamine and inositol. Timecourse incubations revealed that in vitro cultured P. marinus meronts can utilize the cytidine diphosphate-diacylglycerol (CDP-DAG) pathway to synthesize phosphatidylinositol (PI) from inositol and phosphatidylserine (PS) from serine. Serine label was also incorporated into phosphatidylethanolamine (PE), phosphatidylcholine (PC) and lysophosphatidylcholine (LPC). Incubations of P. marinus cells with increasing concentrations of radiolabeled serine resulted in more radioactivity recovered in neutral lipids than in polar lipids at the highest substrate concentration tested (344 microM). This suggests that excess serine label was being utilized for fatty acid synthesis and stored as triacylglycerols. Additional incubations were conducted with radiolabeled choline and ethanolamine at concentrations equimolar to the highest serine concentration tested. Ethanolamine label was also incorporated into PE, PS, PC and LPC. Choline label was incorporated into PC. These results suggest the presence of three pathways for de novo synthesis of phospholipids in P. marinus: CDP-choline, CDP-ethanolamine and CDP-DAG. At equivalent substrate concentrations (344 microM) the highest incorporation of labeled substrate into total phospholipids was with serine followed by ethanolamine and choline, respectively. P. marinus phospholipid biosynthetic capabilities appear to be similar to those of Plasmodium and Trypanosoma species. PMID:12034458

  7. Does ovary need D-chiro-inositol?

    PubMed Central

    2012-01-01

    Backgroud Polycystic Ovary Syndrome (PCOS) is a multifactorial pathology that affects 10% of the women in reproductive age being the main cause of infertility due to menstrual dysfunction. Since 1980, it is known that PCOS is associated with insulin resistance (IR). The recognition of this association has prompted extensive investigation on the relationship between insulin and gonadal function, and has turned insulin sensitizer agent as the main therapeutic choice. In particular two different polyalcohol myo-inositol and D-chiro-inositol have been shown to improve insulin resistance, hyperandrogenism and to induce ovulation in PCOS women. In particular, while data on myo-inositol and restored ovulation were consistent, data on D-chiro-inositol were not . Recently, a comparative study, proposed a D-chiro-inositol paradox in the ovary of PCOS patients hypothesizing that only myo-inositol has a specific ovarian action. In the present study we aim to further study the role played by D-chiro-inositol at ovarian level. Methods A total of 54 women, aged <40 years and diagnosed with PCOS were enrolled in this study. Patients with insulin resistance and/or hyperglycaemia were excluded from the study. Patients were randomly divided into 5 groups (n=10-12): a placebo group, and 4 groups (A-D) that received 300-600-1200-2400 mg of DCI daily respectively. All treatments were carried out for 8 weeks before follicle stimulating hormone (rFSH) administration. Results Total r-FSH units increased significantly in the two groups that received the higher doses of DCI. The number of immature oocytes was significantly increased in the three groups that received the higher doses of DCI. Concurrently, the number of MII oocytes was significantly lower in the D group compared to placebo group. Noteworthy, the number of grade I embryos was significantly reduced by DCI supplementation. Conclusions Indeed, increasing DCI dosage progressively worsens oocyte quality and ovarian response. PMID

  8. Surfactant phospholipid metabolism.

    PubMed

    Agassandian, Marianna; Mallampalli, Rama K

    2013-03-01

    Pulmonary surfactant is essential for life and is composed 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. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism. PMID:23026158

  9. Myo-inositol content of common foods: development of a high-myo-inositol diet.

    PubMed

    Clements, R S; Darnell, B

    1980-09-01

    Since virtually no information is available concerning the myo-inositol content of dietary constituents, we have measured the amount of this material present in 487 foods by gas-liquid chromatography. We observed that the greatest amounts of myo-inositol were present in fruits, beans, grains, and nuts. Fresh vegetables and fruits were found to contain more myo-inositol than did frozen, canned, or salt-free products. The data provided in this report were used to develop diets that contained varying, but known amounts of myo-inositol. The myo-inositol intake that could be provided by such diets ranged from 225 to 1500 mg/day per 1800 kcal and within this range the agreement between the calculated and measured amounts of this material was excellent (r = 0.98). Since abnormalities in the metabolism of myo-inositol have been speculated to play a role in the pathogenesis of the polyneuropathies associated with diabetes mellitus and chronic renal failure, it is possible that the natural history of these neuropahties can be altered by modifying the amount of dietary myo-inositol that is ingested by patients with these diseases. PMID:7416064

  10. 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

  11. 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...

  12. 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...

  13. 21 CFR 184.1370 - Inositol.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 150, which is incorporated... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Inositol. 184.1370 Section 184.1370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  14. 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. PMID:27211661

  15. Turnover of inositol pentakisphosphates, inositol hexakisphosphate and diphosphoinositol polyphosphates in primary cultured hepatocytes.

    PubMed Central

    Glennon, M C; Shears, S B

    1993-01-01

    We have used a non-transformed cell model, the primary cultured hepatocyte, to explore the turnover of inositol hexakisphosphate, multiple isomers of inositol pentakisphosphate and two novel diphosphoinositol polyphosphates. All of these compounds gradually accumulated radioactivity throughout a 70 h period of labelling with [3H]inositol. However, a rapid metabolic rate was revealed upon inhibition of diphosphoinositol polyphosphate biphosphatase(s) with 1 mM fluoride for 40 min: this treatment elevated levels of [3H]diphosphoinositol polyphosphates up to 10-fold, indicating that their cellular pools were normally turning over at least 10 times every 40 min. This was accompanied by a turnover of about 10% of the pool of inositol hexakisphosphate. Control experiments established that 200 nM vasopressin brought about a typical activation of phospholipase C in hepatocytes after 62 h of primary culture. This agonist treatment did not affect steady-state levels of [3H]inositol pentakisphosphates, [3H]inositol hexakisphosphate or [3H]diphosphoinositol polyphosphates. However, prolonged treatment of hepatocytes with 2 microM thapsigargin reduced steady-state levels of [3H]diphosphoinositol polyphosphates by 50-70%. This effect of thapsigargin was also observed in the presence of fluoride, indicating that thapsigargin inhibited the rate of synthesis of diphosphoinositol polyphosphates. PMID:8343137

  16. Inositol pyrophosphates inhibit synaptotagmin-dependent exocytosis.

    PubMed

    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

    2016-07-19

    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 Ca(2+) 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 Ca(2+) levels. Thus, 5-IP7 appears to act through Syt1 binding to interfere with the fusogenic activity of Ca(2+) 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

  17. Comparison of S. cerevisiae F-BAR domain structures reveals a conserved inositol phosphate binding site

    PubMed Central

    Moravcevic, Katarina; Alvarado, Diego; Schmitz, Karl R.; Kenniston, Jon A.; Mendrola, Jeannine M.; Ferguson, Kathryn M.; Lemmon, Mark A.

    2015-01-01

    SUMMARY F-BAR domains control membrane interactions in endocytosis, cytokinesis, and cell signaling. Although 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, we compare membrane-binding properties of the S. 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 to 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. Our findings reveal previously unappreciated determinants of F-BAR domain lipid-binding specificity, and provide a basis for its prediction from sequence. PMID:25620000

  18. Desumoylation of the Endoplasmic Reticulum Membrane VAP Family Protein Scs2 by Ulp1 and SUMO Regulation of the Inositol Synthesis Pathway

    PubMed Central

    Felberbaum, Rachael; Wilson, Nicole R.; Cheng, Dongmei; Peng, Junmin

    2012-01-01

    Posttranslational protein modification by the ubiquitin-like SUMO protein is critical to eukaryotic cell regulation, but much remains unknown regarding its operation and substrates. Here we report that specific mutations in the Saccharomyces cerevisiae Ulp1 SUMO protease, including its coiled-coil (CC) domain, lead to the accumulation of distinct sumoylated proteins in vivo. A prominent ∼50-kDa sumoylated protein accumulates in a Ulp1 CC mutant. The protein was identified as Scs2, an endoplasmic reticulum (ER) membrane protein that regulates phosphatidylinositol synthesis and lipid trafficking. Mutation of lysine 180 of Scs2 abolishes its sumoylation. Notably, impairment of either cellular sumoylation or cellular desumoylation mechanisms inhibits cell growth in the absence of inositol and exacerbates the inositol auxotrophy caused by deletion of SCS2. Mutants lacking the Ulp2 SUMO protease are the most severely affected, and this defect was traced to the mutants' impaired ability to induce transcription of INO1, which encodes the rate-limiting enzyme of inositol biosynthesis. Conversely, inositol starvation induces a striking change in the profiles of total cellular SUMO conjugates. These results provide the first evidence of cross-regulation between the SUMO and inositol pathways, including the sumoylation of an ER membrane protein central to phospholipid synthesis and phosphoinositide signaling. PMID:22025676

  19. Disruption of inositol biosynthesis through targeted mutagenesis in Dictyostelium discoideum: generation and characterization of inositol-auxotrophic mutants.

    PubMed

    Fischbach, Andreas; Adelt, Stephan; Müller, Alexander; Vogel, Günter

    2006-08-01

    myo-Inositol and its downstream metabolites participate in diverse physiological processes. Nevertheless, considering their variety, it is likely that additional roles are yet to be uncovered. Biosynthesis of myo-inositol takes place via an evolutionarily conserved metabolic pathway and is strictly dependent on inositol-3-phosphate synthase (EC 5.5.1.4). Genetic manipulation of this enzyme will disrupt the cellular inositol supply. Two methods, based on gene deletion and antisense strategy, were used to generate mutants of the cellular slime mould Dictyostelium discoideum. These mutants are inositol-auxotrophic and show phenotypic changes under inositol starvation. One remarkable attribute is their inability to live by phagocytosis of bacteria, which is the exclusive nutrient source in their natural environment. Cultivated on fluid medium, the mutants lose their viability when deprived of inositol for longer than 24 h. Here, we report a study of the alterations in the first 24 h in cellular inositol, inositol phosphate and phosphoinositide concentrations, whereby a rapidly accumulating phosphorylated compound was detected. After its identification as 2,3-BPG (2,3-bisphosphoglycerate), evidence could be found that the internal disturbances of inositol homoeostasis trigger the accumulation. In a first attempt to characterize this as a physiologically relevant response, the efficient in vitro inhibition of a D. discoideum inositol-polyphosphate 5-phosphatase (EC 3.1.3.56) by 2,3-BPG is presented. PMID:16599905

  20. Disruption of inositol biosynthesis through targeted mutagenesis in Dictyostelium discoideum: generation and characterization of inositol-auxotrophic mutants

    PubMed Central

    Fischbach, Andreas; Adelt, Stephan; Müller, Alexander; Vogel, Günter

    2006-01-01

    myo-Inositol and its downstream metabolites participate in diverse physiological processes. Nevertheless, considering their variety, it is likely that additional roles are yet to be uncovered. Biosynthesis of myo-inositol takes place via an evolutionarily conserved metabolic pathway and is strictly dependent on inositol-3-phosphate synthase (EC 5.5.1.4). Genetic manipulation of this enzyme will disrupt the cellular inositol supply. Two methods, based on gene deletion and antisense strategy, were used to generate mutants of the cellular slime mould Dictyostelium discoideum. These mutants are inositol-auxotrophic and show phenotypic changes under inositol starvation. One remarkable attribute is their inability to live by phagocytosis of bacteria, which is the exclusive nutrient source in their natural environment. Cultivated on fluid medium, the mutants lose their viability when deprived of inositol for longer than 24 h. Here, we report a study of the alterations in the first 24 h in cellular inositol, inositol phosphate and phosphoinositide concentrations, whereby a rapidly accumulating phosphorylated compound was detected. After its identification as 2,3-BPG (2,3-bisphosphoglycerate), evidence could be found that the internal disturbances of inositol homoeostasis trigger the accumulation. In a first attempt to characterize this as a physiologically relevant response, the efficient in vitro inhibition of a D. discoideum inositol-polyphosphate 5-phosphatase (EC 3.1.3.56) by 2,3-BPG is presented. PMID:16599905

  1. 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.

  2. Extraction and analysis of soluble inositol polyphosphates from yeast.

    PubMed

    Azevedo, Cristina; Saiardi, Adolfo

    2006-01-01

    Soluble inositol polyphosphates are implicated in the regulation of many important cellular functions. This protocol to extract and separate inositol polyphosphates from Saccharomyces cerevisiae is divided into three steps: labeling of yeast, extraction of soluble inositol polyphosphates and chromatographic separation. Yeast cells are incubated with tritiated inositol, which is taken up and metabolized into different phosphorylated forms. Soluble inositol polyphosphates are then acid-extracted and fractionated by high-performance liquid chromatography. The radioactivity of each fraction is determined by scintillation counting. This highly sensitive and reproducible method allows the accurate detection of subtle changes in the inositol polyphosphate profile and takes less than 48 h. It can easily be applied to other systems and we have included two adaptations of the protocol, one optimized for mammalian cells and the other for Arabidopsis thaliana. PMID:17406485

  3. Addenda to the Preceding Paper

    NASA Astrophysics Data System (ADS)

    Bhatnagar, Rajat; Finn, Robert

    2016-05-01

    This work contains largely afterthoughts, relating to the paper immediately preceding it. We correlate and interpret our contributions in that paper, relative to those of an earlier publication by Aspley, He and McCuan. We propose specific laboratory experiments, suggested by formal predictions of those two papers.

  4. 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. PMID:23902363

  5. 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 precedence designators are available...

  6. Characterization of the inositol monophosphatase gene family in Arabidopsis

    PubMed Central

    Nourbakhsh, Aida; Collakova, Eva; Gillaspy, Glenda E.

    2015-01-01

    Synthesis of myo-inositol is crucial in multicellular eukaryotes for production of phosphatidylinositol and inositol phosphate signaling molecules. The myo-inositol monophosphatase (IMP) enzyme is required for the synthesis of myo-inositol, breakdown of inositol (1,4,5)-trisphosphate, a second messenger involved in Ca2+ signaling, and synthesis of L-galactose, a precursor of ascorbic acid. Two myo-inositol monophosphatase -like (IMPL) genes in Arabidopsis encode chloroplast proteins with homology to the prokaryotic IMPs and one of these, IMPL2, can complement a bacterial histidinol 1-phosphate phosphatase mutant defective in histidine synthesis, indicating an important role for IMPL2 in amino acid synthesis. To delineate how this small gene family functions in inositol synthesis and metabolism, we sought to compare recombinant enzyme activities, expression patterns, and impact of genetic loss-of-function mutations for each. Our data show that purified IMPL2 protein is an active histidinol-phosphate phosphatase enzyme in contrast to the IMPL1 enzyme, which has the ability to hydrolyze D-galactose 1-phosphate, and D-myo-inositol 1-phosphate, a breakdown product of D-inositol (1,4,5) trisphosphate. Expression studies indicated that all three genes are expressed in multiple tissues, however, IMPL1 expression is restricted to above-ground tissues only. Identification and characterization of impl1 and impl2 mutants revealed no viable mutants for IMPL1, while two different impl2 mutants were identified and shown to be severely compromised in growth, which can be rescued by histidine. Analyses of metabolite levels in impl2 and complemented mutants reveals impl2 mutant growth is impacted by alterations in the histidine biosynthesis pathway, but does not impact myo-inositol synthesis. Together, these data indicate that IMPL2 functions in the histidine biosynthetic pathway, while IMP and IMPL1 catalyze the hydrolysis of inositol- and galactose-phosphates in the plant cell

  7. 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.

  8. 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

  9. Formation of inositol 1,4,5-trisphosphate and inositol 1,3,4-trisphosphate from inositol 1,3,4,5-tetrakisphosphate and their pathways of degradation in RBL-2H3 cells

    SciTech Connect

    Cunha-Melo, J.R.; Dean, N.M.; Ali, H.; Beaven, M.A.

    1988-10-05

    Previous studies with antigen-stimulated rat basophilic leukemia (RBL-2H3) cells indicated the formation of multiple isomers of each of the various categories of inositol phosphates. The identities of the different isomers have been elucidated by selective labeling of (3H)inositol 1,3,4,5-tetrakisphosphate with (32P)phosphate in the 3'-or 4',5'-positions and by following the metabolism of different radiolabeled inositol phosphates in extracts of RBL-2H3 cells. We report here that inositol 1,3,4,5-tetrakisphosphate, when incubated with the membrane fraction of extracts of RBL-2H3 cells, was converted to inositol 1,4,5-trisphosphate and inositol 1,3,4-trisphosphate. Further dephosphorylation of the inositol polyphosphates proceeded rapidly in whole extracts of cells, although the process was significantly retarded when ATP (2 mM) levels were maintained by an ATP-regenerating system. The degradation of inositol 1,4,5-trisphosphate proceeded with the sequential formation of inositol 1,4-bisphosphate, the inositol 4-monophosphate (with smaller amounts of the 1-monophosphate), and finally inositol. Inositol 1,3,4-trisphosphate, on the other hand, was converted to inositol 1,3-bisphosphate and inositol 3,4-bisphosphate and subsequently to inositol 4-monophosphate and inositol 1-monophosphate (stereoisomeric forms were undetermined). The possible implications of the apparent interconversion between inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate in regulating histamine secretion in the RBL-2H3 cells are discussed.

  10. Behavioral evidence for the existence of two pools of cellular inositol.

    PubMed

    Bersudsky, Y; Kaplan, Z; Shapiro, Y; Agam, G; Kofman, O; Belmaker, R H

    1994-12-01

    Lithium reduces brain inositol levels by inhibiting inositol monophosphatase. In a previous study it was found that administration of pilocarpine to Li-treated rats causes limbic seizure behavior which can be reversed by i.c.v. myo-inositol but not chiro-inositol, suggesting that this behavior is related to inositol depletion in the PI cycle. Hyponatremia can lower brain inositol and hypernatremia can raise brain inositol. We now report that induction of low brain inositol by hyponatremia followed by pilocarpine did not cause limbic seizures. Induction of high brain inositol using hypernatremia followed by Li-pilocarpine administration did not reverse limbic seizures. These data support the concept that inositol available for P1 synthesis and inositol for osmotic function are sequestered in different cellular pools. PMID:7894256

  11. 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.

  12. 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

  13. 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

  14. 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. PMID:25734537

  15. 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

  16. 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...

  17. 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. PMID:25679134

  18. 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.

  19. Interactions of amelogenin with phospholipids.

    PubMed

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

    2015-02-01

    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, 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. 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

  20. Purification and biochemical characterization of Mycobacterium tuberculosis SuhB, an inositol monophosphatase involved in inositol biosynthesis.

    PubMed

    Nigou, Jérôme; Dover, Lynn G; Besra, Gurdyal S

    2002-04-01

    Phosphatidylinositol is an essential component of mycobacteria, and phosphatidylinositol-based lipids such as phosphatidylinositolmannosides, lipomannan, and lipoarabinomannan are major immunomodulatory components of the Mycobacterium tuberculosis cell wall. Inositol monophosphatase (EC 3.1.3.25) is a crucial enzyme in the biosynthesis of free myo-inositol from inositol-1-phosphate, a key substrate for the phosphatidylinositol synthase in mycobacteria. Analysis of the M. tuberculosis genome suggested the presence of four M. tuberculosis gene products that exhibit an inositol monophosphatase signature. In the present report, we have focused on SuhB, which possesses the highest degree of homology with human inositol monophosphatase. SuhB gene was cloned into an E. coli expression vector to over-produce a His-tagged protein, which was purified and characterized. SuhB required divalent metal ions for functional inositol monophosphatase activity, with Mg(2+) being the strongest activator. Inositol monophosphatase activity catalyzed by SuhB was inhibited by the monovalent cation lithium (IC(50) = 0.9 mM). As anticipated, inositol-1-phosphate was the preferred substrate (K(m) = 0.177 +/- 0.025 mM; k(cat) = 3.6 +/- 0.2 s(-)(1)); however, SuhB was also able to hydrolyze a variety of polyol phosphates such as glucitol-6-phosphate, glycerol-2-phosphate, and 2'-AMP. To provide further insight into the structure-function relationship of SuhB, different mutant proteins were generated (E83D, D104N, D107N, W234L, and D235N). These mutations almost completely abrogated inositol monophosphatase activity, thus underlining the importance of these residues in inositol-1-phosphate dephosphorylation. We also identified L81 as a key residue involved in sensitivity to lithium. The L81A mutation rendered SuhB inositol monophosphatase activity 10-fold more resistant to inhibition by lithium (IC(50) = 10 mM). These studies provide the first steps in the delineation of the biosynthesis of the

  1. Convenient synthesis of 4,6-di-O-benzyl-myo-inositol and myo-inositol 1,3,5-orthoesters.

    PubMed

    Praveen, T; Shashidhar, M S

    2001-02-15

    Convenient high yielding methods for the preparation of 4,6-di-O-benzyl-myo-inositol, myo-inositol 1,3,5-orthoformate and myo-inositol 1,3,5-orthoacetate, without involving chromatography are described. Myo-inositol was converted to racemic 2,4-di-O-benzoyl-myo-inositol 1,3,5-orthoformate by successive treatment with triethyl orthoformate and benzoyl chloride. The dibenzoate obtained on benzylation with benzyl bromide and silver(I) oxide gave 2-O-benzoyl-4,6-di-O-benzyl-myo-inositol 1,3,5-orthoformate. Deprotection of the benzoate and the orthoformate with isobutylamine and aqueous trifluoroacetic acid, respectively gave 4,6-di-O-benzyl-myo-inositol in an overall yield of 67%. Myo-inositol orthoformate and orthoacetate were prepared and isolated as their tribenzoates. The free orthoesters were regenerated by deprotection of the benzoates by aminolysis with isobutylamine. PMID:11270820

  2. [Phospholipids: properties and health effects].

    PubMed

    Torres García, Jairo; Durán Agüero, Samuel

    2015-01-01

    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. PMID:25561100

  3. Trimetazidine effect on phospholipid synthesis in ventricular myocytes: consequences in alpha-adrenergic signaling.

    PubMed

    Tabbi-Anneni, Iméne; Lucien, Arnaud; Grynberg, Alain

    2003-02-01

    The anti-anginal drug trimetazidine (TMZ) has been shown to increase the synthesis of phospholipids in ventricular myocytes, including phosphatidyl-inositol (PI). This study focused on the consequences of increasing PI metabolism on alpha-adrenergic signaling pathway in cultured rat cardiomyocytes. In the cells treated with TMZ, the synthesis of PI from inositol was largely increased as compared with the control (+55% in 60 min). The stimulation of alpha-adrenergic receptors by phenylephrine (PE) induced a dose-dependent production of inositide phosphates (IPs) by phospholipase C (PLC) activation. However, the amount of available IPs was significantly lower in TMZ-treated cells, in a dose-dependent manner. This effect was observed in the presence and absence of the IP1-phosphatase inhibitor LiCl. The in vitro determination of PLC activity revealed that this effect could not be attributed to the direct inhibition of the enzyme by TMZ. The TMZ-induced reduction of IPs in the PE-stimulated cardiomyocytes should be attributed to the increase of inositol recycling and incorporation in membrane structures, elicited by increased phospholipid synthesis. The consequences of this reduction in IPs availability were investigated on the cardiomyocyte hypertrophy induced by alpha-adrenergic chronic stimulation. Acute stimulation with PE increased protein synthesis (+50%), but this increase was largely prevented by TMZ. In conclusion, TMZ reduces cell available IPs, by accelerating their recycling in membranes as PI. This effect results in a cytoprotection in the pathological process of hypertrophy elicited by chronic alpha-adrenergic stimulation. PMID:12588630

  4. Inositol hexaphosphate and inositol inhibit DMBA-induced rat mammary cancer.

    PubMed

    Vucenik, I; Yang, G Y; Shamsuddin, A M

    1995-05-01

    Because inositol hexaphosphate (InsP6) and inositol (Ins), contained in plants and most mammalian cells, have been demonstrated to have anti-cancer and anti-cell proliferative action in several experimental models of carcinogenesis we have examined the effect of InsP6 +/- Ins on DMBA-induced rat mammary tumor model. Starting two weeks prior to induction with DMBA, the drinking water of female Sprague-Dawley rats was supplemented with either: 15 mM InsP6, 15 mM Ins, or 15 mM InsP6 + 15 mM Ins; a control group received no inositol compounds. Animals (49-day-old) were given a single intragastric dose of DMBA (5 mg/rat) in 1 ml of corn oil administered by oral intubation. After 45 weeks of treatment, the animals in all the three treatment regimens showed a significant reduction (P < 0.05) in tumor incidence. Tumor number, multiplicity and tumor burden were also significantly (P < 0.05) reduced by InsP6 +/- Ins. When all the parameters were taken into consideration, the best results were obtained by the combination treatment of InsP6 + Ins. Four additional groups not receiving DMBA, but drinking tap water, InsP6, Ins, or InsP6 + Ins of the same molarity as experimental groups were observed for the duration of the study to monitor for any toxicity following this long-term treatment; no significant toxicity as evaluated by body weight gain, serum and bone mineral levels was detected. We demonstrate that InsP6 +/- Ins reproducibly inhibits experimental mammary carcinoma, therefore having great potential as a chemopreventive and adjuvant therapeutic agent for this disease as well. PMID:7767964

  5. 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

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

    PubMed

    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; Williams, Robin S B

    2016-05-15

    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

  7. 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

  8. 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.

  9. 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. PMID:26177098

  10. Synthesis of inositol phosphate-based competitive antagonists of inositol 1,4,5-trisphosphate receptors.

    PubMed

    Konieczny, Vera; Stefanakis, John G; Sitsanidis, Efstratios D; Ioannidou, Natalia-Anastasia T; Papadopoulos, Nikolaos V; Fylaktakidou, Konstantina C; Taylor, Colin W; Koumbis, Alexandros E

    2016-02-16

    Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular Ca(2+) channels that are widely expressed in animal cells, where they mediate the release of Ca(2+) from intracellular stores evoked by extracellular stimuli. A diverse array of synthetic agonists of IP3Rs has defined structure-activity relationships, but existing antagonists have severe limitations. We combined analyses of Ca(2+) release with equilibrium competition binding to IP3R to show that (1,3,4,6)IP4 is a full agonist of IP3R1 with lower affinity than (1,4,5)IP3. Systematic manipulation of this meso-compound via a versatile synthetic scheme provided a family of dimeric analogs of 2-O-butyryl-(1,3,4,6)IP4 and (1,3,4,5,6)IP5 that compete with (1,4,5)IP3 for binding to IP3R without evoking Ca(2+) release. These novel analogs are the first inositol phosphate-based competitive antagonists of IP3Rs with affinities comparable to that of the only commonly used competitive antagonist, heparin, the utility of which is limited by off-target effects. PMID:26818818

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

    PubMed

    Mayr, G W

    1989-04-15

    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

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

    PubMed Central

    Mallows, R S; Bolton, T B

    1987-01-01

    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. PMID:2451504

  13. 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. PMID:26916021

  14. Inositol and Sugars in Adaptation of Tomato to Salt 1

    PubMed Central

    Sacher, Robert F.; Staples, Richard C.

    1985-01-01

    Tomato (Lycopersicon esculentum Mill. cv New Yorker) plants subjected to 100 millimolar NaCl plus Hoagland nutrients exhibited a pattern of wilting, recovery of turgor, and finally recovery of growth at a reduced level, which required 3 days. During the nongrowing, adaptation phase there were immediate increases in free hexoses and sucrose which declined to near control levels as growth resumed. There was a steady increase in myo-inositol content which reached its maximal level at the time of growth resumption. The myo-inositol level then remained elevated for the remainder of the experiment. Myo-inositol constituted two-thirds of the soluble carbohydrate in leaves and three-fourths of the soluble carbohydrate in roots of salt-adapted plants. Plants which were alternated daily between salt and control solutions accumulated less myo-inositol and exhibited less growth than the continuously salt-treated plants. In L. pennellii and in salt-tolerant and salt-sensitive breeding lines selected from L. esculentum × L. pennellii BC(1) and F(8), myo-inositol content was highest in the most tolerant genotypes, intermediate in the normal cultivar, and lowest in the sensitive genotype after treatment with salt. PMID:16664009

  15. 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.

  16. [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. PMID:22586936

  17. 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

  18. 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

  19. Inositols affect the mating circadian rhythm of Drosophila melanogaster

    PubMed Central

    Sakata, Kazuki; Kawasaki, Haruhisa; Suzuki, Takahiro; Ito, Kumpei; Negishi, Osamu; Tsuno, Takuo; Tsuno, Hiromi; Yamazaki, Youta; Ishida, Norio

    2015-01-01

    Accumulating evidence indicates that the molecular circadian clock underlies the mating behavior of Drosophila melanogaster. However, information about which food components affect circadian mating behavior is scant. The ice plant, Mesembryanthemum crystallinum has recently become a popular functional food. Here, we showed that the close-proximity (CP) rhythm of D. melanogaster courtship behavior was damped under low-nutrient conditions, but significantly enhanced by feeding the flies with powdered ice plant. Among various components of ice plants, we found that myo-inositol increased the amplitude and slightly shortened the period of the CP rhythm. Real-time reporter assays showed that myo-inositol and D-pinitol shortened the period of the circadian reporter gene Per2-luc in NIH 3T3 cells. These data suggest that the ice plant is a useful functional food and that the ability of inositols to shorten rhythms is a general phenomenon in insects as well as mammals. PMID:26097456

  20. ‘Trigger’ Events Precede Calcium Puffs in Xenopus Oocytes

    PubMed Central

    Rose, Heather J.; Dargan, Sheila; Shuai, Jianwei; Parker, Ian

    2006-01-01

    The liberation of calcium ions sequestered in the endoplasmic reticulum through inositol 1,4,5-trisphosphate receptors/channels (IP3Rs) results in a spatiotemporal hierarchy of calcium signaling events that range from single-channel openings to local Ca2+ puffs believed to arise from several to tens of clustered IP3Rs to global calcium waves. Using high-resolution confocal linescan imaging and a sensitive Ca2+ indicator dye (fluo-4-dextran), we show that puffs are often preceded by small, transient Ca2+ elevations that we christen “trigger events”. The magnitude of triggers is consistent with their arising from the opening of a single IP3 receptor/channel, and we propose that they initiate puffs by recruiting neighboring IP3Rs within the cluster by a regenerative process of Ca2+-induced Ca2+ release. Puff amplitudes (fluorescence ratio change) are on average ∼6 times greater than that of the triggers, suggesting that at least six IP3Rs may simultaneously be open during a puff. Trigger events have average durations of ∼12 ms, as compared to 19 ms for the mean rise time of puffs, and their spatial extent is ∼3 times smaller than puffs (respective widths at half peak amplitude 0.6 and 1.6 μm). All these parameters were relatively independent of IP3 concentration, although the proportion of puffs showing resolved triggers was greatest (∼80%) at low [IP3]. Because Ca2+ puffs constitute the building blocks from which cellular IP3-mediated Ca2+ signals are constructed, the events that initiate them are likely to be of fundamental importance for cell signaling. Moreover, the trigger events provide a useful yardstick by which to derive information regarding the number and spatial arrangement of IP3Rs within clusters. PMID:16980363

  1. Insulin stimulates the generation from hepatic plasma membranes of modulators derived from an inositol glycolipid.

    PubMed Central

    Saltiel, A R; Cuatrecasas, P

    1986-01-01

    Insulin binding to plasma membrane receptors results in the generation of substances that acutely mimic the actions of the hormone on certain target enzymes. Two such substances, which modulate the activity of the high-affinity cAMP phosphodiesterase (EC 3.1.4.17), have been purified from hepatic plasma membranes. The two have similar properties and activities but can be resolved by ion-exchange chromatography and high-voltage electrophoresis. They exhibit a net negative charge, even at pH 1.9, and an apparent molecular weight of approximately 1400. The generation of these substances from membranes by insulin can be reproduced by addition of a phosphatidylinositol-specific phospholipase C purified from Staphylococcus aureus. This enzyme is known to selectively hydrolyze phosphatidylinositol and release from membranes several proteins that are covalently linked to phosphatidylinositol by a glycan anchor. Both enzyme-modulating substances appear to be generated by the phosphodiesterase cleavage of a phosphatidylinositol-containing glycolipid precursor that has been characterized by thin-layer chromatography. Some of the chemical properties of these substances have been examined. They appear to be related complex carbohydrate-phosphate substances containing glucosamine and inositol. These findings suggest that insulin may activate a selective phospholipase activity that hydrolyzes a membrane phospholipid, releasing a carbohydrate-containing molecule that regulates cAMP phosphodiesterase and perhaps other insulin-sensitive enzymes. PMID:3016721

  2. 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

  3. 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

    2016-01-01

    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. 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. PMID:15337459

  5. Functional properties of Drosophila inositol trisphosphate receptors.

    PubMed Central

    Swatton, J E; Morris, S A; Wissing, F; Taylor, C W

    2001-01-01

    The functional properties of the only inositol trisphosphate (IP(3)) receptor subtype expressed in Drosophila were examined in permeabilized S2 cells. The IP(3) receptors of S2 cells bound (1,4,5)IP(3) with high affinity (K(d)=8.5+/-1.1 nM), mediated positively co-operative Ca(2+) release from a thapsigargin-sensitive Ca(2+) store (EC(50)=75+/-4 nM, Hill coefficient=2.1+/-0.2), and they were recognized by an antiserum to a peptide conserved in all IP(3) receptor subtypes in the same way as mammalian IP(3) receptors. As with mammalian IP(3) receptors, (2,4,5)IP(3) (EC(50)=2.3+/-0.3 microM) and (4,5)IP(2) (EC(50) approx. 10 microM) were approx. 20- and 100-fold less potent than (1,4,5)IP(3). Adenophostin A, which is typically approx. 10-fold more potent than IP(3) at mammalian IP(3) receptors, was 46-fold more potent than IP(3) in S2 cells (EC(50)=1.67+/-0.07 nM). Responses to submaximal concentrations of IP(3) were quantal and IP(3)-evoked Ca(2+) release was biphasically regulated by cytosolic Ca(2+). Using rapid superfusion to examine the kinetics of IP(3)-evoked Ca(2+) release from S2 cells, we established that IP(3) (10 microM) maximally activated Drosophila IP(3) receptors within 400 ms. The activity of the receptors then slowly decayed (t(1/2)=2.03+/-0.07 s) to a stable state which had 47+/-1% of the activity of the maximally active state. We conclude that the single subtype of IP(3) receptor expressed in Drosophila has similar functional properties to mammalian IP(3) receptors and that analyses of IP(3) receptor function in this genetically tractable organism are therefore likely to contribute to understanding the roles of mammalian IP(3) receptors. PMID:11583592

  6. 8 CFR 103.10 - Precedent decisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... General are governed by part 1003 of 8 CFR chapter V. (b) Decisions as precedents. Except as Board... provided in paragraph (c) of this section or 8 CFR 1003.1(h)(2). (d) Publication of Secretary's...

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

    PubMed

    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

  8. 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

  9. Probing myo-inositol 1-phosphate synthase with multisubstrate adducts

    PubMed Central

    Deranieh, Rania M.; Greenberg, Miriam L.; Le Calvez, Pierre-B.; Mooney, Maura C.; Migaud, Marie E.

    2015-01-01

    The synthesis of a series of carbohydrate-nucleotide hybrids, designed to be multisubstrate adducts mimicking myo-inositol 1-phosphate synthase first oxidative transition state, is reported. Their ability to inhibit the synthase has been assessed and results have been rationalised computationally to estimate their likely binding mode. PMID:23132282

  10. Lithium and valproate decrease inositol mass and increase expression of the yeast INO1 and INO2 genes for inositol biosynthesis.

    PubMed

    Vaden, D L; Ding, D; Peterson, B; Greenberg, M L

    2001-05-01

    Bipolar affective disorder (manic-depressive illness) is a chronic, severe, debilitating illness affecting 1-2% of the population. The Food and Drug Administration-approved drugs lithium and valproate are not completely effective in the treatment of this disorder, and the mechanisms underlying their therapeutic effects have not been established. We are employing genetic and molecular approaches to identify common targets of lithium and valproate in the yeast Saccharomyces cerevisiae. We show that both drugs affect molecular targets in the inositol metabolic pathway. Lithium and valproate cause a decrease in intracellular myo-inositol mass and an increase in expression of both a structural (INO1) and a regulatory (INO2) gene required for inositol biosynthesis. The opi1 mutant, which exhibits constitutive expression of INO1, is more resistant to inhibition of growth by lithium but not by valproate, suggesting that valproate may inhibit the Ino1p-catalyzed synthesis of inositol 1-phosphate. Consistent with this possibility, growth in valproate leads to decreased synthesis of inositol monophosphate. Thus, both lithium and valproate perturb regulation of the inositol biosynthetic pathway, albeit via different mechanisms. This is the first demonstration of increased expression of genes in the inositol biosynthetic pathway by both lithium and valproate. Because inositol is a key regulator of many cellular processes, the effects of lithium and valproate on inositol synthesis have far-reaching implications for predicting genetic determinants of responsiveness and resistance to these agents. PMID:11278273

  11. Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION.

    PubMed

    Deranieh, Rania M; Shi, Yihui; Tarsio, Maureen; Chen, Yan; McCaffery, J Michael; Kane, Patricia M; Greenberg, Miriam L

    2015-11-13

    Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase. PMID:26324718

  12. 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

  13. 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.

  14. 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

  15. 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

  16. Phospholipid composition of cultured human endothelial cells.

    PubMed

    Murphy, E J; Joseph, L; Stephens, R; Horrocks, L A

    1992-02-01

    Detailed analyses of the phospholipid compositions of cultured human endothelial cells are reported here. No significant differences were found between the phospholipid compositions of cells from human artery, saphenous and umbilical vein. However, due to the small sample sizes, relatively large standard deviations for some of the phospholipid classes were observed. A representative composition of endothelial cells is: phosphatidylcholine 36.6%, choline plasmalogen 3.7%, phosphatidylethanolamine 10.2%, ethanolamine plasmalogen 7.6%, sphingomyelin 10.8%, phosphatidylserine 7.1%, lysophosphatidylcholine 7.5%, phosphatidylinositol 3.1%, lysophosphatidylethanolamine 3.6%, phosphatidylinositol 4,5-bisphosphate 1.8%, phosphatidic acid 1.9%, phosphatidylinositol 4-phosphate 1.5%, and cardiolipin 1.9%. The cells possess high choline plasmalogen and lysophosphatidylethanolamine contents. The other phospholipids are within the normal biological ranges expected. Phospholipids were separated by high-performance liquid chromatography and quantified by lipid phosphorus assay. PMID:1315902

  17. Extensive exchange of rat liver microsomal phospholipids.

    PubMed

    Zilversmit, D B; Hughes, M E

    1977-08-15

    Liver microsomal fractions were prepared from rats injected with a single dose of choline [14C]methylchloride or with single or multiple doses of 32Pi. Exchangeability of microsomal phospholipids was determined by incubation with an excess of mitochondria and phospholipid exchange proteins derived from beef heart, beef liver or rat liver. Labeled phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol were found to act as a single pool and were 85--95% exchangeable in 1--2h. High latencies of mannose-6-phosphate phosphohydrolase activities and impermeability of microsomes to EDTA proved that phospholipid exchange proteins did not have access to the intracisternal space. If microsomal membranes are largely composed of phospholipid bilayers, the experiments suggest that one or more of the phospholipid classes in microsomal membranes undergo rapid translocation between the inner and outer portions of the bilayer. PMID:889827

  18. Patterning and characterization of model phospholipid membranes

    NASA Astrophysics Data System (ADS)

    Kassu, Aschalew; Calzzani, Fernando A., Jr.; Taguenang, Jean M.; Sileshi, Redahegn K.; Sharma, Anup

    2008-08-01

    Phospholipid, which is a building block of biological membranes, plays an important role in compartmentalization of cellular reaction environment and control of the physicochemical conditions inside the reaction environment. Phospholipid bilayer membrane has been proposed as a natural biocompatible platform for attaching biological molecules like proteins for biosensing related application. Due to the enormous potential applications of biomimetic model biomembranes, various techniques for depositions and patterning of these membranes onto solid supports and their possible biotechnological applications have been reported by different groups. In this work, patterning of phospholipid thin-films is accomplished by interferometric lithography as well as using lithographic masks in liquid phase. Surface Enhanced Raman Spectroscopy and Atomic Force microscopy are used to characterize the model phospholipid membrane and the patterning technique. We describe an easy and reproducible technique for direct patterning of azo-dye (NBD)-labeled phospholipid (phosphatidylcholine) in aqueous medium using a low-intensity 488 nm Ar+ laser and various kinds of lithographic masks.

  19. 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

  20. Identification of a functional 2-keto-myo-inositol dehydratase gene of Sinorhizobium fredii USDA191 required for myo-inositol utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sinorhizobium fredii USDA191 is a Gram-negative bacterium capable of forming nitrogen-fixing nodules on soybean roots. The USDA191 idhA gene encoding myo-inositol dehydrogenase, an enzyme necessary for myo-inositol utilization, is known to be involved in competitive nodulation and nitrogen fixation....

  1. 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.

  2. 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)

  3. 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…

  4. 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

  5. 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,…

  6. Huntington's disease: Neural dysfunction linked to inositol polyphosphate multikinase.

    PubMed

    Ahmed, Ishrat; Sbodio, Juan I; Harraz, Maged M; Tyagi, Richa; Grima, Jonathan C; Albacarys, Lauren K; Hubbi, Maimon E; Xu, Risheng; Kim, Seyun; Paul, Bindu D; Snyder, Solomon H

    2015-08-01

    Huntington's disease (HD) is a progressive neurodegenerative disease caused by a glutamine repeat expansion in mutant huntingtin (mHtt). Despite the known genetic cause of HD, the pathophysiology of this disease remains to be elucidated. Inositol polyphosphate multikinase (IPMK) is an enzyme that displays soluble inositol phosphate kinase activity, lipid kinase activity, and various noncatalytic interactions. We report a severe loss of IPMK in the striatum of HD patients and in several cellular and animal models of the disease. This depletion reflects mHtt-induced impairment of COUP-TF-interacting protein 2 (Ctip2), a striatal-enriched transcription factor for IPMK, as well as alterations in IPMK protein stability. IPMK overexpression reverses the metabolic activity deficit in a cell model of HD. IPMK depletion appears to mediate neural dysfunction, because intrastriatal delivery of IPMK abates the progression of motor abnormalities and rescues striatal pathology in transgenic murine models of HD. PMID:26195796

  7. 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. PMID:24966051

  8. Mitochondrial phospholipids: role in mitochondrial function.

    PubMed

    Mejia, Edgard M; Hatch, Grant M

    2016-04-01

    Mitochondria are essential components of eukaryotic cells and are involved in a diverse set of cellular processes that include ATP production, cellular signalling, apoptosis and cell growth. These organelles are thought to have originated from a symbiotic relationship between prokaryotic cells in an effort to provide a bioenergetic jump and thus, the greater complexity observed in eukaryotes (Lane and Martin 2010). Mitochondrial processes are required not only for the maintenance of cellular homeostasis, but also allow cell to cell and tissue to tissue communication (Nunnari and Suomalainen 2012). Mitochondrial phospholipids are important components of this system. Phospholipids make up the characteristic outer and inner membranes that give mitochondria their shape. In addition, these membranes house sterols, sphingolipids and a wide variety of proteins. It is the phospholipids that also give rise to other characteristic mitochondrial structures such as cristae (formed from the invaginations of the inner mitochondrial membrane), the matrix (area within cristae) and the intermembrane space (IMS) which separates the outer mitochondrial membrane (OMM) and inner mitochondrial membrane (IMM). Phospholipids are the building blocks that make up these structures. However, the phospholipid composition of the OMM and IMM is unique in each membrane. Mitochondria are able to synthesize some of the phospholipids it requires, but the majority of cellular lipid biosynthesis takes place in the endoplasmic reticulum (ER) in conjunction with the Golgi apparatus (Fagone and Jackowski 2009). In this review, we will focus on the role that mitochondrial phospholipids play in specific cellular functions and discuss their biosynthesis, metabolism and transport as well as the differences between the OMM and IMM phospholipid composition. Finally, we will focus on the human diseases that result from disturbances to mitochondrial phospholipids and the current research being performed to help

  9. Structure of inositol monophosphatase, the putative target of lithium therapy.

    PubMed Central

    Bone, R; Springer, J P; Atack, J R

    1992-01-01

    Inositol monophosphatase (EC 3.1.3.25), the putative molecular site of action of lithium therapy for manic-depressive illness, plays a key role in the phosphatidylinositol signaling pathway by catalyzing the hydrolysis of inositol monophosphates. To provide a structural basis from which to design better therapeutic agents for manic-depressive illness, the structure of human inositol monophosphatase has been determined to 2.1-A resolution by using x-ray crystallography. The enzyme exists as a dimer of identical subunits, each folded into a five-layered sandwich of three pairs of alpha-helices and two beta-sheets. Sulfate and an inhibitory lanthanide cation (Gd3+) are bound at identical sites on each subunit and establish the positions of the active sites. Each site is located in a large hydrophilic cavern that is at the base of the two central helices where several segments of secondary structure intersect. Comparison of the phosphatase aligned sequences of several diverse genes with the phosphatase structure suggests that the products of these genes and the phosphatase form a structural family with a conserved metal binding site. Images PMID:1332026

  10. Clinical relevance of multiple antibody specificity testing in anti-phospholipid syndrome and recurrent pregnancy loss

    PubMed Central

    Tebo, A E; Jaskowski, T D; Hill, H R; Branch, D W

    2008-01-01

    We wanted to evaluate whether testing for anti-phosholipid antibodies other than anti-cardiolipin (aCL) and anti-beta-2 glycoprotein I (aβ2GPI) immunoglobulin (Ig)G and IgM identifies patients with recurrent pregnancy loss (RPL) who may be positive for anti-phospholipid syndrome (APS). In a cross-sectional study comprising 62 patients with APS, 66 women with RPL, 50 healthy blood donors and 24 women with a history of successful pregnancies, we tested IgM and IgG antibodies to phosphatidic acid, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol and phosphatidyl serine with and without beta-2 glycoprotein I (β2GPI) from a single manufacturer as well as aCL and aβ2GPI antibodies. Diagnostic accuracies of individual and combined anti-phospholipid (aPL) assays were assessed by computing sensitivities, specificities, positive predictive values and negative predictive values together with their 95% confidence intervals. There was a general trend for increased sensitivities in the presence of β2GPI co-factor with significant effect for certain specificities. The overall combined sensitivity of the non-recommended aPL assays was not significantly higher than that of the aCL and aB2GPI tests. Multiple aPL specificities in RPL group is not significantly different from controls and therefore of no clinical significance. PMID:18826497

  11. Clinical relevance of multiple antibody specificity testing in anti-phospholipid syndrome and recurrent pregnancy loss.

    PubMed

    Tebo, A E; Jaskowski, T D; Hill, H R; Branch, D W

    2008-12-01

    We wanted to evaluate whether testing for anti-phosholipid antibodies other than anti-cardiolipin (aCL) and anti-beta-2 glycoprotein I (abeta2GPI) immunoglobulin (Ig)G and IgM identifies patients with recurrent pregnancy loss (RPL) who may be positive for anti-phospholipid syndrome (APS). In a cross-sectional study comprising 62 patients with APS, 66 women with RPL, 50 healthy blood donors and 24 women with a history of successful pregnancies, we tested IgM and IgG antibodies to phosphatidic acid, phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl glycerol, phosphatidyl inositol and phosphatidyl serine with and without beta-2 glycoprotein I (beta2GPI) from a single manufacturer as well as aCL and abeta2GPI antibodies. Diagnostic accuracies of individual and combined anti-phospholipid (aPL) assays were assessed by computing sensitivities, specificities, positive predictive values and negative predictive values together with their 95% confidence intervals. There was a general trend for increased sensitivities in the presence of beta2GPI co-factor with significant effect for certain specificities. The overall combined sensitivity of the non-recommended aPL assays was not significantly higher than that of the aCL and aB2GPI tests. Multiple aPL specificities in RPL group is not significantly different from controls and therefore of no clinical significance. PMID:18826497

  12. 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

  13. myo-Inositol 1,3-acetals as early intermediates during the synthesis of cyclitol derivatives.

    PubMed

    Gurale, Bharat P; Sardessai, Richa S; Shashidhar, Mysore S

    2014-11-18

    Synthetic sequences starting from commercially available myo-inositol necessarily involve protection-deprotection strategies of its six hydroxyl groups. Several strategies have been developed/attempted over the last several decades leading to the synthesis of naturally occurring phosphoinositols, their analogs, and cyclitol derivatives. Of late, myo-inositol 1,3-acetals, which can be obtained by the reductive cleavage of myo-inositol orthoesters have emerged as early intermediates for the synthesis of phosphorylated and other inositol derivatives. This mini-review is an attempt to illustrate the economy and convenience of using myo-inositol 1,3-acetals as early intermediates during syntheses from myo-inositol. PMID:25216930

  14. 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.

  15. Threshold of the precedence effect in noise

    PubMed Central

    Freyman, Richard L.; Griffin, Amanda M.; Zurek, Patrick M.

    2014-01-01

    Three effects that show a temporal asymmetry in the influence of interaural cues were studied through the addition of masking noise: (1) The transient precedence effect—the perceptual dominance of a leading transient over a similar lagging transient; (2) the ongoing precedence effect—lead dominance with lead and lag components that extend in time; and (3) the onset capture effect—determination by an onset transient of the lateral position of an otherwise ambiguous extended trailing sound. These three effects were evoked with noise-burst stimuli and were compared in the presence of masking noise. Using a diotic noise masker, detection thresholds for stimuli with lead/lag interaural delays of 0/500 μs were compared to those with 500/0 μs delays. None of the three effects showed a masking difference between those conditions, suggesting that none of the effects is operative at masked threshold. A task requiring the discrimination between stimuli with 500/0 and 0/500 μs interaural delays was used to determine the threshold for each effect in noise. The results showed similar thresholds in noise (10–13 dB SL) for the transient and ongoing precedence effects, but a much higher threshold (33 dB SL) for onset capture of an ambiguous trailing sound. PMID:24815272

  16. [Phospholipids metabolism disorders in acute stroke].

    PubMed

    Solovieva, E Yu; Farrahova, K I; Karneev, A N; Chipova, D T

    2016-01-01

    The disturbances of cerebral circulation results in the violation of phospholipid metabolism. Activation of lipid peroxidation and protein kinase C and release of intracellular calcium leads to disruption of the homeostasis of phosphatidylcholine. The use of cytidine-5-diphosphocholine, which is used as an intermediate compound in the biosynthesis of phospholipids of the cell membrane, helps to stabilize cell membranes, and reduce the formation of free radicals. PMID:27045147

  17. Regulation of cell-specific inositol metabolism and transport in plant salinity tolerance.

    PubMed Central

    Nelson, D E; Rammesmayer, G; Bohnert, H J

    1998-01-01

    myo-Inositol and its derivatives are commonly studied with respect to cell signaling and membrane biogenesis, but they also participate in responses to salinity in animals and plants. In this study, we focused on L-myo-inositol 1-phosphate synthase (INPS), which commits carbon to de novo synthesis, and myo-inositol O-methyltransferase (IMT), which uses myo-inositol for stress-induced accumulation of a methylinositol, D-ononitol. The Imt and Inps promoters are transcriptionally controlled. We determined that the transcription rates, transcript levels, and protein abundance are correlated. During normal growth, INPS is present in all cells, but IMT is repressed. After salinity stress, the amount of INPS was enhanced in leaves but repressed in roots. IMT was induced in all cell types. The absence of myo-inositol synthesis in roots is compensated by inositol/ononitol transport in the phloem. The mobilization of photosynthate through myo-inositol translocation links root metabolism to photosynthesis. Our model integrates the transcriptional control of a specialized metabolic pathway with physiological reactions in different tissues. The tissue-specific differential regulation of INPS, which leads to a gradient of myo-inositol synthesis, supports root growth and sodium uptake. By inducing expression of IMT and increasing myo-inositol synthesis, metabolic end products accumulate, facilitating sodium sequestration and protecting photosynthesis. PMID:9596634

  18. Phospholipids and fatty acids of Neisseria gonorrhoeae.

    PubMed Central

    Sud, I J; Feingold, D S

    1975-01-01

    The phospholipids and fatty acids of two strains of Neisseria gonorrhoeae of different penicillin susceptibilities were examined. The phospholipids, which comprise about 8% of the dry weight of the cells, consisted of phosphatidylethanolamine (70%) and phosphatidylglycerol (20%); small amounts of phosphatidylcholine and traces of cardiolipin were also present. Growing and stationary-phase cells were similar in content and composition of phospholipids except for phosphatidylcholine, which increased two- to fivefold in the stationary-phase cells. The fatty acids of the phospholipids were characterized by two major acids, palmitic and a C16:1, with myristic and a C18:1 acid present in smaller amounts. The fatty acids present in purified phospholipid fractions varied considerably in relative proportions from fraction to fraction. No significant difference in the composition of phospholipids from the two strains was evident. Large amounts of beta-hydroxy lauric acid were detected only after saponification of the organisms. Differences in the lipid composition between the gonococcus and other gram-negative bacteria are discussed. PMID:810478

  19. 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). PMID:26479434

  20. Membrane-derived phospholipids control synaptic neurotransmission and plasticity.

    PubMed

    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

    2015-05-01

    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

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

    PubMed Central

    Butterwick, Joel A.; MacKinnon, Roderick

    2010-01-01

    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 and physical properties of the surrounding membrane environment. To learn about VSD-lipid interactions, we used nuclear magnetic resonance (NMR) spectroscopy to determine the structure and phospholipid interface of the VSD from the voltage-dependent K+ channel KvAP. The solution structure of the KvAP VSD solubilized within phospholipid micelles is similar to a previously determined crystal structure solubilized by a non-ionic detergent and complexed with an antibody fragment. Two 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 15N relaxation experiments, we show that most of the VSD, including the pronounced kink in S3 and the S3-S4 paddle, is relatively rigid on the ps–ns time scale. In contrast, the kink in S3 is mobile on the μs–ms time scale 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 show 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. PMID:20851706

  2. 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

  3. 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. PMID:27544399

  4. Myo-Inositol Supplementation to Prevent Gestational Diabetes Mellitus.

    PubMed

    Celentano, Claudio; Matarrelli, Barbara; Mattei, Peter A; Pavone, Giulia; Vitacolonna, Ester; Liberati, Marco

    2016-03-01

    Gestational diabetes mellitus (GDM) is a common complication characterized by increased insulin resistance, and by increased risk for adverse pregnancy outcomes affecting both the mother and the fetus. International guidelines describe optimal ways to recognize it, and the recommended treatment of patients affected to reduce adverse outcomes. Improving insulin resistance could reduce incidence of GDM and its complications. Recently, a few trials have been published on the possible prevention of GDM. Inositol has been proposed as a food supplement that might reduce gestational diabetes incidence in high-risk pregnant women. PMID:26898405

  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. 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

  7. Inositol and its derivatives: their evolution and functions.

    PubMed

    Michell, Robert H

    2011-01-01

    Ins and Ins phospholipids are present in and are made by most Archaea and all eukaryotes. Relatively few bacteria possess Ins phospholipids: and only one major grouping, the Actinobacteria, is known to have evolved multiple functions for Ins derivatives. The Ins phospholipids of all organisms, whether they have diradylglycerol or ceramide backbones, seem to use the same Ins1P headgroup stereochemistry, so they are probably made by evolutionarily conserved pathways. It seems likely that an early member of the Archaea made the first phospholipid with an Ins1P headgroup -maybe three billionyears ago – and that amuchlater archaeal descendentwas the ancestral contributor that brought these molecules into the common ancestor of all eukaryotes – maybe two billionyears ago (Michell, 2007, 2008). It will only be possible to infer the likely details of these processes when we have learned much more about the Ins lipid biochemistry of modern archaeons. All eukaryotes make substantial amounts of PtdIns, both as a ‘bulk’ membrane phospholipid and as the precursor of seven phosphorylated derivatives of PtdIns (the polyphosphoinositides; PPIn) and of the ‘GPI anchors’ of cell surface ectoproteins. PtdIns(4,5)P2 – with its many functions – and its precursor PtdIns4P are found in all in eukaryotes. So are PtdIns3P and PtdIns(3,5)P2, which have ubiquitous roles in the regulation of membrane trafficking events. However, synthesis of and signalling by PtdIns(3,4,5) P 3 appears to be confined to a later-evolved group of eukaryotes. PMID:21070803

  8. 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.

  9. A functional myo-inositol catabolism pathway is essential for rhizopine utilization by Sinorhizobium meliloti.

    PubMed

    Galbraith, M P; Feng, S F; Borneman, J; Triplett, E W; de Bruijn, F J; Rossbach, S

    1998-10-01

    Rhizopine (L-3-O-methyl-scyllo-inosamine) is a symbiosis-specific compound found in alfalfa nodules induced by specific Sinorhizobium meliloti strains. It has been postulated that rhizobial strains able to synthesize and catabolize rhizopine gain a competitive advantage in the rhizosphere. The pathway of rhizopine degradation is analysed here. Since rhizopine is an inositol derivative, it was tested whether inositol catabolism is involved in rhizopine utilization. A genetic locus required for the catabolism of inositol as sole carbon source was cloned from S. meliloti. This locus was delimited by transposon Tn5 mutagenesis and its DNA sequence was determined. Based on DNA similarity studies and enzyme assays, this genetic region was shown to encode an S. meliloti myo-inositol dehydrogenase. Strains that harboured a mutation in the myo-inositol dehydrogenase gene (idhA) did not display myo-inositol dehydrogenase activity, were unable to utilize myo-inositol as sole carbon/energy source, and were unable to catabolize rhizopine. Thus, myo-inositol dehydrogenase activity is essential for rhizopine utilization in S. meliloti. PMID:9802033

  10. Inositol induces mesenchymal-epithelial reversion in breast cancer cells through cytoskeleton rearrangement.

    PubMed

    Dinicola, Simona; Fabrizi, Gianmarco; Masiello, Maria Grazia; Proietti, Sara; Palombo, Alessandro; Minini, Mirko; Harrath, Abdel Halim; Alwasel, Saleh H; Ricci, Giulia; Catizone, Angela; Cucina, Alessandra; Bizzarri, Mariano

    2016-07-01

    Inositol displays multi-targeted effects on many biochemical pathways involved in epithelial-mesenchymal transition (EMT). As Akt activation is inhibited by inositol, we investigated if such effect could hamper EMT in MDA-MB-231 breast cancer cells. In cancer cells treated with pharmacological doses of inositol E-cadherin was increased, β-catenin was redistributed behind cell membrane, and metalloproteinase-9 was significantly reduced, while motility and invading capacity were severely inhibited. Those changes were associated with a significant down-regulation of PI3K/Akt activity, leading to a decrease in downstream signaling effectors: NF-kB, COX-2, and SNAI1. Inositol-mediated inhibition of PS1 leads to lowered Notch 1 release, thus contributing in decreasing SNAI1 levels. Overall, these data indicated that inositol inhibits the principal molecular pathway supporting EMT. Similar results were obtained in ZR-75, a highly metastatic breast cancer line. These findings are coupled with significant changes on cytoskeleton. Inositol slowed-down vimentin expression in cells placed behind the wound-healing edge and stabilized cortical F-actin. Moreover, lamellipodia and filopodia, two specific membrane extensions enabling cell migration and invasiveness, were no longer detectable after inositol addiction. Additionally, fascin and cofilin, two mandatory required components for F-actin assembling within cell protrusions, were highly reduced. These data suggest that inositol may induce an EMT reversion in breast cancer cells, suppressing motility and invasiveness through cytoskeleton modifications. PMID:27237097

  11. Polyhydroxyalkanoate (PHA) Granules Have no Phospholipids.

    PubMed

    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

  12. 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

  13. 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. PMID:25990651

  14. Generation of phytate-free seeds in Arabidopsis through disruption of inositol polyphosphate kinases

    PubMed Central

    Stevenson-Paulik, Jill; Bastidas, Robert J.; Chiou, Shean-Tai; Frye, Roy A.; York, John D.

    2005-01-01

    Phytate (inositol hexakisphosphate, IP6) is a regulator of intracellular signaling, a highly abundant animal antinutrient, and a phosphate store in plant seeds. Here, we report a requirement for inositol polyphosphate kinases, AtIPK1 and AtIPK2β, for the later steps of phytate synthesis in Arabidopsis thaliana. Coincident disruption of these kinases nearly ablates seed phytate without accumulation of phytate precursors, increases seed-free phosphate by 10-fold, and has normal seed yield. Additionally, we find a requirement for inositol tetrakisphosphate (IP4)/inositol pentakisphosphate (IP5) 2-kinase activity in phosphate sensing and root hair elongation. Our results define a commercially viable strategy for the genetic engineering of phytate-free grain and provide insights into the role of inositol polyphosphate kinases in phosphate signaling biology. PMID:16107538

  15. 1 L-myo-Inositol 1-Phosphate Synthase from Arabidopsis thaliana.

    PubMed Central

    Johnson, M. D.; Sussex, I. M.

    1995-01-01

    A recombinant phage containing an Arabidopsis thaliana cDNA sequence encoding a protein with 1L-myo-inositol 1-phosphate synthase (EC 5.5.1.4) activity has been isolated and used for transcriptional and translational studies. The identification of the recombinant phage relied on the observations that (a) the clone complements a mutation in the structural gene for 1L-myo-inositol 1-phosphate synthase in the yeast Saccharomyces cerevisiae, (b) the in vitro synthesized polypeptide enzymatically converts glucose 6-phosphate into inositol 1-phosphate, (c) in vitro transcription and translation of this cDNA sequence produces a polypeptide that is recognized by anti-yeast myo-inositol 1-phosphate synthase antiserum, and (d) inositol regulates the expression of the corresponding gene in Arabidopsis. PMID:12228386

  16. 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

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

    PubMed

    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

  18. Structure of HDAC3 bound to corepressor and inositol tetraphosphate

    PubMed Central

    Watson, Peter J.; Fairall, Louise; Santos, Guilherme M.; Schwabe, John W.R.

    2011-01-01

    Summary Histone deacetylase enzymes (HDACs) are emerging cancer drug targets. They regulate gene expression by removing acetyl groups from lysine residues in histone tails resulting in chromatin condensation. The enzymatic activity of most class I HDACs requires recruitment to corepressor complexes. We report the first structure of an HDAC:corepressor complex - HDAC3 with the deacetylase-activation-domain (DAD) from the SMRT corepressor. The structure reveals two remarkable features. First the SMRT-DAD undergoes a large structural rearrangement on forming the complex. Second there is an essential inositol tetraphosphate molecule, Ins(1,4,5,6)P4, acting as an ‘intermolecular glue’ between the two proteins. Assembly of the complex is clearly dependent on the Ins(1,4,5,6)P4, which may act as a regulator – potentially explaining why inositol phosphates and their kinases have been found to act as transcriptional regulators. This mechanism for the activation of HDAC3 appears to be conserved in class I HDACs from yeast to man and opens novel therapeutic opportunities. PMID:22230954

  19. 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

  20. 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. PMID:8633761

  1. Phospholipids accumulation in mucolipidosis IV cultured fibroblasts.

    PubMed

    Bargal, R; Bach, G

    1988-01-01

    Cultured fibroblasts from mucolipidosis IV patients accumulated phospholipids when compared to normal controls or cells from other genotypes. The major stored compounds were identified as phosphatidylcholine, phosphatidylethanolamine and to a larger extent lysophosphatidylcholine and lysobisphosphatidic acid. Pulse chase experiments of 32P-labelled phospholipids showed increased retention of these compounds in the mucolipidosis IV lines throughout the pulse and chase periods. Phospholipase A1, A2, C, D and lysophospholipase showed normal activity in the mucolipidosis IV lines and thus the metabolic cause for this storage remains to be identified. PMID:3139925

  2. Phospholipid exchange reactions within the liver cell

    PubMed Central

    McMurray, W. C.; Dawson, R. M. C.

    1969-01-01

    1. Isolated rat liver mitochondria do not synthesize labelled phosphatidylcholine from CDP-[14C]choline or any phospholipid other than phosphatidic acid from [32P]phosphate. The minimal labelling of phosphatidylcholine and other phosphoglycerides can be attributed to microsomal contamination. However, when mitochondria and microsomes are incubated together with [32P]phosphate, the phosphatidylcholine, phosphatidylinositol and phosphatidylethanolamine of the reisolated mitochondria become labelled, suggesting a transfer of phospholipids between the two fractions. 2. When liver microsomes or mitochondria containing labelled phosphatidylcholine are independently incubated with the opposite un-labelled fraction, there is a substantial and rapid exchange of the phospholipid between the two membranes. Exchange of phosphatidylinositol also occurs rapidly, whereas phosphatidylethanolamine and phosphatidic acid exchange only slowly. There is no corresponding transfer of marker enzymes. The transfer of phosphatidylcholine does not occur at 0°, and there is no requirement for added substrate, ATP or Mg2+, but the omission of a heat-labile supernatant fraction markedly decreases the exchange. 3. After intravenous injection of [32P]phosphate, short-period labelling experiments of the individual phospholipids of rat liver microsomes and mitochondria in vivo give no evidence for a similar exchange process. However, the incubation of isolated microsomes and mitochondria with [32P]phosphate also fails on reisolation of the fractions to demonstrate a precursor–product relationship between the individual phospholipids of the two membranes. 4. The intraperitoneal injection of [32P]phosphate results in a far greater proportion of the dose entering the liver than does intravenous administration. After intraperitoneal administration of [32P]phosphate the specific radioactivities of the individual phospholipids are in the order microsomes > outer mitochondrial membrane > inner

  3. [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. PMID:23768570

  4. Precedence effects and the evolution of chorusing

    PubMed Central

    Greenfield, M. D.; Tourtellot, M. K.; Snedden, W. A.

    1997-01-01

    The structured choruses produced by rhythmically signalling males in many species of acoustic animals have long-captured the imagination of evolutionary biologists. Though various hypotheses have been forwarded to explain the adaptive significance of such chorusing, none have withstood empirical scrutiny. We suggest instead that alternating and synchronous choruses represent collective epiphenomena resulting from individual males competing to jam each other's signals. These competitions originate in psychoacoustic precedence effects wherein females only orient toward the first call of a sequence, thus selectively favouring males who produce leading calls. Given this perceptual bias, our modelling confirms that a resetting of signal rhythm by neighbours' signals, which generates either alternation or synchrony, is evolutionarily stable provided that resetting includes a relativity adjustment for the velocity of signal transmission and selective attention toward only a subset of signalling neighbours. Signalling strategies in chorusing insects and anurans are consistent with these predicted features.

  5. 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.

  6. 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

  7. Effects of aluminium on the hepatic inositol polyphosphate phosphatase.

    PubMed Central

    Ali, N; Craxton, A; Sumner, M; Shears, S B

    1995-01-01

    There is speculation that some of the toxic effects of Al3+ may originate from it perturbing inositol phosphate/Ca2+ signalling. For example, in permeabilized L1210 mouse lymphoma cells, 10-50 microM Al3+ activated Ins(1,3,4,5)P4-dependent Ca2+ mobilization and Ins(1,3,4,5)P4 3-phosphatase activity [Loomis-Husselbee, Cullen, Irvine and Dawson (1991) Biochem. J. 277, 883-885]. Ins(1,3,4,5)P4 3-phosphatase activity is performed by a multiple inositol polyphosphate phosphatase (MIPP) that also attacks Ins(1,3,4,5,6)P5 and InsP6 [Craxton, Ali and Shears (1995) Biochem. J. 305, 491-498]: 5-50 microM Al3+ increased MIPP activity towards both Ins(1,3,4,5)P4 (by 30%) and Ins(1,3,4,5,6)P5 (by up to 500%), without affecting metabolism of InsP6. Higher concentrations of Al3+ inhibited metabolism of all three substrates, and in the case of InsP6, Al3+ altered the pattern of accumulating products. When 1-50 microM Al3+ was present, InsP6 became a less effective inhibitor of Ins(1,3,4,5)P4 3-phosphatase activity; this effect did not depend on the presence of cellular membranes, contrary to a previous proposal. The latter phenomenon largely explains how, in a cell-free system where Ins(1,3,4,5)P4 3-phosphatase is inhibited by endogenous InsP6, the addition of Al3+ can apparently increase the enzyme activity. However, there was no effect of either 10 or 25 microM Al3+ (in either the presence or absence of apotransferrin) on inositol phosphate profiles in either Jurkat E6-1 lymphoma cells or AR4-2J pancreatoma cells. PMID:7832774

  8. Stimulation of phospholipid hydrolysis and arachidonic acid mobilization in human uterine decidua cells by phorbol ester.

    PubMed Central

    Schrey, M P; Read, A M; Steer, P J

    1987-01-01

    Vasopressin and oxytocin both stimulated inositol phosphate accumulation in isolated uterine decidua cells. Pretreatment of cells with the phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) prevented this agonist-induced phosphoinositide hydrolysis. TPA (0.1 microM) alone had no effect on basal inositol phosphate accumulation, but stimulated phosphoinositide deacylation, as indicated by a 2-fold increase in lysophosphatidylinositol and glycerophosphoinositol. TPA also stimulated a dose-related release of arachidonic acid from decidua-cell phospholipid [phosphatidylcholine (PC) much greater than phosphatidylinositol (PI) greater than phosphatidylethanolamine]. The phorbol ester 4 beta-phorbol 12,13-diacetate (PDA) at 0.1 microM had no effect on arachidonic acid mobilization. The TPA-stimulated increase in arachidonic acid release was apparent by 2 1/2 min (116% of control), maximal after 20 min (283% of control), and remained around this value (306% of control) after 120 min incubation. TPA also stimulated significant increases in 1,2-diacylglycerol and monoacylglycerol production at 20 and 120 min. Although the temporal increases in arachidonic acid and monoacylglycerol accumulation in the presence of TPA continued up to 120 min, that of 1,2-diacylglycerol declined after 20 min. In decidua cells prelabelled with [3H]choline, TPA also stimulated a significant decrease in radiolabelled PC after 20 min, which was accompanied by an increased release of water-soluble metabolites into the medium. Most of the radioactivity in the extracellular pool was associated with choline, whereas the main cellular water-soluble metabolite was phosphorylcholine. TPA stimulated extracellular choline accumulation to 183% and 351% of basal release after 5 and 20 min respectively and cellular phosphorylcholine production to 136% of basal values after 20 min. These results are consistent with a model in which protein kinase C activation by TPA leads to arachidonic acid mobilization

  9. Effect of 1,25-dihydroxyvitamin D3 on phospholipid metabolism in cultured bovine parathyroid cells.

    PubMed

    Sugimoto, T; Ritter, C; Slatopolsky, E; Morrissey, J

    1988-06-01

    There is evidence that 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] affects phospholipid metabolism of intestine, kidney, and bone. There are no such studies concerning the parathyroid gland, which is also a target tissue for 1,25-(OH)2D3. In this investigation we examined the effect of 1,25-(OH)2D3 on the incorporation of radiolabeled choline, inositol, serine, and ethanolamine into the phospholipids of cultured bovine parathyroid cells. Treatment with 10(-8) M 1,25-(OH)2D3 for 48 h caused a significant decrease in [14C]choline incorporation, although there were no differences in the incorporation of radiolabeled inositol, serine, or ethanolamine. Time-course and dose-response evaluations of the 1,25-(OH)2D3 effect revealed that the decrease in [14C]choline incorporation was seen within 12 h of incubation and occurred with as little as 10(-9) M, respectively. In contrast, neither 10(-7) M 25-hydroxyvitamin D3 nor 10(-7) M 24,25-(OH)2D3 caused significant changes in [14C]choline incorporation. When 5 X 10(-6) M cycloheximide was added to the medium, the inhibitory effect of 1,25-(OH)2D3 on [14C]choline incorporation was completely abolished. A significant decrease in phosphatidylcholine content was observed after treatment with 10(-8) M 1,25-(OH)2D3 for 96 h. 1,25-(OH)2D3 did not cause a dramatic change in the fatty acid composition of the phosphatidylcholine. The present studies demonstrate that in parathyroid cells 1,25-(OH)2D3 causes a decrease in [14C]choline incorporation, which could be due to a decrease in the synthesis of phosphatidylcholine or increased degradation. This effect is specific for 1,25-(OH)2D3 and requires new protein synthesis. PMID:3131114

  10. Phospholipid association with the bovine cardiac mitochondrial adenosine triphosphatase.

    PubMed Central

    Brown, R E; Montgomery, R I; Spach, P I; Cunningham, C C

    1985-01-01

    The association of different phospholipids with a lipid-depleted oligomycin-sensitive ATPase from bovine cardiac mitochondria [Serrano, Kanner & Racker (1976) J. Biol. Chem. 251, 2453-2461] has been examined using three approaches. First, reconstitution of the ATPase with different synthetic diacyl phospholipids resulted in a 2-10-fold stimulation of ATPase specific activity depending upon the particular phospholipid employed. The phospholipid headgroup region displayed the following order of ATPase reactivation potential: dioleoylphosphatidylglycerol greater than dioleoylphosphatidic acid greater than dioleoylphosphatidylcholine. Furthermore, the ATPase showed higher levels of specific activity when reconstituted with dioleoyl phospholipid derivatives compared with dimyristoyl derivatives. Second, examination of the phospholipid remaining associated with the lipid-depleted ATPase upon purification showed that phosphatidylcholine, phosphatidylethanolamine, and diphosphatidylglycerol were present. No relative enrichment of any of these phospholipids (compared with their distribution in submitochondrial particles) was noted. Therefore, no preferential association between the ATPase and any one phospholipid could be found in the mitochondrial ATPase. Third, the sodium cholate-mediated phospholipid exchange procedure was employed for studying the phospholipid requirements of the ATPase. Replacement of about 50% of the mitochondrial phospholipid remaining with the lipid-depleted ATPase could be achieved utilizing either synthetic phosphatidic acid or phosphatidylcholine. Examination of the displaced mitochondrial phospholipid showed that phosphatidylcholine, phosphatidylethanolamine, and diphosphatidylglycerol were replaced with equal facility. Images Fig. 3. PMID:3156584

  11. 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

  12. 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. PMID:3176021

  13. Effects of inositol supplementation in a cohort of mothers at risk of producing an NTD pregnancy.

    PubMed

    Cavalli, Pietro; Tonni, Gabriele; Grosso, Enrico; Poggiani, Carlo

    2011-11-01

    Neural tube defects (NTDs), most commonly spina bifida and anencephaly, can be prevented with periconceptional intake of folic acid in about 70% of cases. Recurrence of NTDs despite supplementation of high dose of folic acid further suggests that a proportion of NTD cases might be resistant to folic acid. Moreover, heterogeneity of NTDs has been suggested in animal studies, indicating that only some sub-type of NTDs should be considered sensitive to folate intake. Inositol isomers (particularly myo- and chiro-inositol) can prevent folate-resistant NTDs in the curly-tail mutant mouse, suggesting that some cases of human NTDs might benefit from inositol supplementation. In humans, lower inositol blood concentration was found in pregnant women carrying NTD fetuses, whereas a periconceptional combination therapy with folic acid associated with inositol has been linked to normal live births, despite high NTD recurrence risk. Fifteen pregnancies from 12 Caucasian women from different parts of Italy with at least one previous NTD-affected pregnancy underwent periconceptional combined myo-inositol and folic acid supplementation. Maternal serum α-feto-protein levels were found in the normal range, and normal results on ultrasound examination were found in all the pregnancies that followed. No collateral effects or intense uterine contractions were demonstrated in this pilot study in any of the pregnancies after inositol supplementation, and seventeen babies were born without any type of NTD. PMID:21956977

  14. 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.

  15. Regulation of myo-inositol biosynthesis by p53-ISYNA1 pathway.

    PubMed

    Koguchi, Tomoyuki; Tanikawa, Chizu; Mori, Jinichi; Kojima, Yoshiyuki; Matsuda, Koichi

    2016-06-01

    In response to various cellular stresses, p53 exerts its tumor suppressive effects such as apoptosis, cell cycle arrest, and senescence through the induction of its target genes. Recently, p53 was shown to control cellular homeostasis by regulating energy metabolism, glycolysis, antioxidant effect, and autophagy. However, its function in inositol synthesis was not reported. Through a microarray screening, we found that five genes related with myo-inositol metabolism were induced by p53. DNA damage enhanced intracellular myo-inositol content in HCT116 p53+/+ cells, but not in HCT116 p53-/- cells. We also indicated that inositol 3-phosphate synthase (ISYNA1) which encodes an enzyme essential for myo-inositol biosynthesis as a direct target of p53. Activated p53 regulated ISYNA1 expression through p53 response element in the seventh exon. Ectopic ISYNA1 expression increased myo-inositol levels in the cells and suppressed tumor cell growth. Knockdown of ISYNA1 caused resistance to adriamycin treatment, demonstrating the role of ISYNA1 in p53-mediated growth suppression. Furthermore, ISYNA1 expression was significantly associated with p53 mutation in bladder, breast cancer, head and neck squamous cell carcinoma, lung squamous cell carcinoma, and pancreatic adenocarcinoma. Our findings revealed a novel role of p53 in myo-inositol biosynthesis which could be a potential therapeutic target. PMID:27035231

  16. 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. PMID:11900279

  17. Interaction of phospholipid with silver nanorods

    NASA Astrophysics Data System (ADS)

    Anju, K. N.; Mahesh, S.; Kalarikkal, Nandakumar

    2014-01-01

    Development of a simple method for incorporating phospholipids onto the surfaces of anisotropic silver nanorods as a stepping-stone for creating responsive and multifunctional nanocomposites. 1, 2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC)-silver nanorod composites were prepared by immobilizing liposomes onto the surface of cetyltrimethylammonium bromide (CTAB) capped silver nanorods. Here we report the role of phospholipids to control the self assembly of silver nanorods into agglomerate architectures ranging from open "end-to-end" networks to densely packed "side-to-side" arrays. The tuning of electrostatic interactions within the phospholipid layers is governed to lipid silver nanorod assembly and also about the organization of phospholipid layers themselves around nanorod surfaces. The initial studies on passive lipid functionalized nanorods could serve as the groundwork for introducing active components into these systems to make more switchable or reconfigurable nanocomposite material. Changing the surface species on silver nanorods from CTAB to DSPC is reflected in ξ- potential measurements. The surface morphology is studied using SEM and TEM. The optical studies are carried out using UV-Vis spectroscopy.

  18. Feruloyl Dioleoyglycerol Antioxidant Capacity in Phospholipid Vesicles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  19. An essential role for an inositol polyphosphate multikinase, Ipk2, in mouse embryogenesis and second messenger production

    PubMed Central

    Frederick, Joshua P.; Mattiske, Deidre; Wofford, Jessica A.; Megosh, Louis C.; Drake, Li Yin; Chiou, Shean-Tai; Hogan, Brigid L. M.; York, John D.

    2005-01-01

    Phospholipase C and several inositol polyphosphate kinase (IPK) activities generate a branched ensemble of inositol polyphosphate second messengers that regulate cellular signaling pathways in the nucleus and cytoplasm. Here, we report that mice deficient for Ipk2 (also known as inositol polyphosphate multikinase), an inositol trisphosphate and tetrakisphosphate 6/5/3-kinase active at several places in the inositol metabolic pathways, die around embryonic day 9.5 with multiple morphological defects, including abnormal folding of the neural tube. Metabolic analysis of Ipk2-deficient cells demonstrates that synthesis of the majority of inositol pentakisphosphate, hexakisphosphate and pyrophosphate species are disrupted, although the presence of 10% residual inositol hexakisphosphate indicates the existence of a minor alternative pathway. Agonist induced inositol tris- and bis-phosphate production and calcium release responses are present in homozygous mutant cells, indicating that the observed mouse phenotypes are a result of failure to produce higher inositol polyphosphates. Our data demonstrate that Ipk2 plays a major role in the synthesis of inositol polyphosphate messengers derived from inositol 1,4,5-trisphosphate and uncovers a role for their production in embryogenesis and normal development. PMID:15939867

  20. 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

    2016-03-01

    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. PMID:26847388

  1. 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.

  2. The biological activity of structurally defined inositol glycans

    PubMed Central

    Goel, Meenakshi; Azev, Viatcheslav N; d’Alarcao, Marc

    2009-01-01

    Background The inositol glycans (IGs) are glycolipid-derived carbohydrates produced by insulin-sensitive cells in response to insulin treatment. IGs exhibit an array of insulin-like activities including stimulation of lipogenesis, glucose transport and glycogen synthesis, suggesting that they may be involved in insulin signal transduction. However, because the natural IGs are structurally heterogeneous and difficult to purify to homogeneity, an understanding of the relationship between structure and biological activity has relied principally on synthetic IGs of defined structure. Discussion This article briefly describes what is known about the role of IGs in signal transduction and reviews the specific biological activities of the structurally defined IGs synthesized and tested to date. Conclusion A pharmacophore for IG activity begins to emerge from the reviewed data and the structural elements necessary for activity are summarized. PMID:20390053

  3. 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. PMID:27080106

  4. Inositol 1,4,5-trisphosphate induced calcium waves

    NASA Astrophysics Data System (ADS)

    Falcke, M.

    Traveling waves of high concentration of Ca2+ are observed in many different cells and have attracted great interest in experimental and theoretical biological research in recent years. They are created by the nonlinear dynamics of the release and uptake of Ca2+ by intracellular Ca2+ stores like the endoplasmatic or sarcoplasmatic reticulum. Their characteristics depend on other cellular organelles and components like mitochondria and Ca2+ buffers too. Here, we present some mathematical models and results of recent research on intracellular Ca2+ waves generated by the inositol 1,4,5-trisphosphate receptor channel including the modeling of Calcium induced Calcium release, buffer dynamics, impact of mitochondria on wave formation and the effect of the spatial discreteness of the channels releasing Ca2+. Modeling of the communication of Ca2+ waves to adjacent cells through gap junctions concludes this report.

  5. 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

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

    PubMed Central

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

    2014-01-01

    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 PMID:25110363

  8. Animal Detection Precedes Access to Scene Category

    PubMed Central

    Crouzet, Sébastien M.; Joubert, Olivier R.; Thorpe, Simon J.; Fabre-Thorpe, Michèle

    2012-01-01

    The processes underlying object recognition are fundamental for the understanding of visual perception. Humans can recognize many objects rapidly even in complex scenes, a task that still presents major challenges for computer vision systems. A common experimental demonstration of this ability is the rapid animal detection protocol, where human participants earliest responses to report the presence/absence of animals in natural scenes are observed at 250–270 ms latencies. One of the hypotheses to account for such speed is that people would not actually recognize an animal per se, but rather base their decision on global scene statistics. These global statistics (also referred to as spatial envelope or gist) have been shown to be computationally easy to process and could thus be used as a proxy for coarse object recognition. Here, using a saccadic choice task, which allows us to investigate a previously inaccessible temporal window of visual processing, we showed that animal – but not vehicle – detection clearly precedes scene categorization. This asynchrony is in addition validated by a late contextual modulation of animal detection, starting simultaneously with the availability of scene category. Interestingly, the advantage for animal over scene categorization is in opposition to the results of simulations using standard computational models. Taken together, these results challenge the idea that rapid animal detection might be based on early access of global scene statistics, and rather suggests a process based on the extraction of specific local complex features that might be hardwired in the visual system. PMID:23251545

  9. 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

  10. 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.

  11. Life events and difficulties preceding stroke.

    PubMed Central

    House, A; Dennis, M; Mogridge, L; Hawton, K; Warlow, C

    1990-01-01

    Life events and difficulties were recorded for the year before stroke, using a standardised semi-structured interview, in 113 surviving patients seen after their first ever in a lifetime stroke. An age and sex-matched control group (n = 109) was also interviewed about the preceding year. The stroke patients reported fewer non-threatening events and events with only a short-term threat, while difficulties were reported with equal frequency by the two groups. However, events which were severely threatening in the long-term were significantly more common in the stroke patients (in the 52 weeks before stroke 26% versus 13%, odds ratio 2.3, 95% confidence interval 1.1-4.9). The increased rate was apparent throughout the year and not just in the weeks immediately before stroke onset. The number of stroke patients experiencing severe events in the follow up year fell to the level found in the control group. Recognised risk factors for stroke were found equally in those patients with and without severe events before onset, except that hypertension was rather less common in the patients who had experienced a severe event. It therefore appears that severe life events may be one of the determinants of stroke onset. PMID:2292691

  12. Metabolic Effects of n-3 PUFA as Phospholipids Are Superior to Triglycerides in Mice Fed a High-Fat Diet: Possible Role of Endocannabinoids

    PubMed Central

    Rossmeisl, Martin; Macek Jilkova, Zuzana; Kuda, Ondrej; Jelenik, Tomas; Medrikova, Dasa; Stankova, Barbora; Kristinsson, Björn; Haraldsson, Gudmundur G.; Svensen, Harald; Stoknes, Iren; Sjövall, Peter; Magnusson, Ylva; Balvers, Michiel G. J.; Verhoeckx, Kitty C. M.; Tvrzicka, Eva; Bryhn, Morten; Kopecky, Jan

    2012-01-01

    Background n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), reduce the risk of cardiovascular disease and can ameliorate many of obesity-associated disorders. We hypothesised that the latter effect will be more pronounced when DHA/EPA is supplemented as phospholipids rather than as triglycerides. Methodology/Principal Findings In a ‘prevention study’, C57BL/6J mice were fed for 9 weeks on either a corn oil-based high-fat obesogenic diet (cHF; lipids ∼35% wt/wt), or cHF-based diets in which corn oil was partially replaced by DHA/EPA, admixed either as phospholipids or triglycerides from marine fish. The reversal of obesity was studied in mice subjected to the preceding cHF-feeding for 4 months. DHA/EPA administered as phospholipids prevented glucose intolerance and tended to reduce obesity better than triglycerides. Lipemia and hepatosteatosis were suppressed more in response to dietary phospholipids, in correlation with better bioavailability of DHA and EPA, and a higher DHA accumulation in the liver, white adipose tissue (WAT), and muscle phospholipids. In dietary obese mice, both DHA/EPA concentrates prevented a further weight gain, reduced plasma lipid levels to a similar extent, and tended to improve glucose tolerance. Importantly, only the phospholipid form reduced plasma insulin and adipocyte hypertrophy, while being more effective in reducing hepatic steatosis and low-grade inflammation of WAT. These beneficial effects were correlated with changes of endocannabinoid metabolome in WAT, where phospholipids reduced 2-arachidonoylglycerol, and were more effective in increasing anti-inflammatory lipids such as N-docosahexaenoylethanolamine. Conclusions/Significance Compared with triglycerides, dietary DHA/EPA administered as phospholipids are superior in preserving a healthy metabolic profile under obesogenic conditions, possibly reflecting better bioavalability and improved modulation of the

  13. Improving D-glucaric acid production from myo-inositol in E. coli by increasing MIOX stability and myo-inositol transport.

    PubMed

    Shiue, Eric; Prather, Kristala L J

    2014-03-01

    D-glucaric acid has been explored for a myriad of potential uses, including biopolymer production and cancer treatment. A biosynthetic route to produce D-glucaric acid from glucose has been constructed in Escherichia coli (Moon et al., 2009b), and analysis of the pathway revealed myo-inositol oxygenase (MIOX) to be the least active enzyme. To increase pathway productivity, we explored protein fusion tags for increased MIOX solubility and directed evolution for increased MIOX activity. An N-terminal SUMO fusion to MIOX resulted in a 75% increase in D-glucaric acid production from myo-inositol. While our directed evolution efforts did not yield an improved MIOX variant, our screen isolated a 941 bp DNA fragment whose expression led to increased myo-inositol transport and a 65% increase in D-glucaric acid production from myo-inositol. Overall, we report the production of up to 4.85 g/L of D-glucaric acid from 10.8 g/L myo-inositol in recombinant E. coli. PMID:24333274

  14. 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. PMID:22361179

  15. Carbachol stimulates a different phospholipid metabolism than nerve growth factor and basic fibroblast growth factor in PC12 cells.

    PubMed Central

    Pessin, M S; Altin, J G; Jarpe, M; Tansley, F; Bradshaw, R A; Raben, D M

    1991-01-01

    We have examined 1,2-diglycerides (DGs) generated in PC12 cells in response to the muscarinic agonist carbachol and compared them with those generated in response to the differentiation factors nerve growth factor and basic fibroblast growth factor. Whereas carbachol stimulates a greater release of inositol phosphates, all three agonists generate similar levels of DGs. In this report, we have analyzed the molecular species of PC12 DGs generated in response to these three agonists. Additionally, we have analyzed the molecular species of PC12 phospholipids. The data indicate that 1) after 1 min of either nerve growth factor or basic fibroblast growth factor stimulation, DGs arise primarily from phosphoinositide hydrolysis; 2) in contrast, after 1 min of carbachol stimulation, DG are generated equally by both phosphoinositide and phosphatidylcholine hydrolysis; and 3) after 15 min of stimulation by any of these agonists, DGs are generated largely by phosphatidylcholine hydrolysis, with a smaller component arising from the phosphoinositides. These results suggest that at least part of the mechanism by which PC12 cells distinguish between different agonists is via alterations in phospholipid sources and kinetics of DG generation. PMID:1892912

  16. 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. PMID:8986742

  17. "Inosaminoacids": novel inositol-amino acid hybrid structures accessed by microbial arene oxidation.

    PubMed

    Pilgrim, Sarah; Kociok-Köhn, Gabriele; Lloyd, Matthew D; Lewis, Simon E

    2011-04-28

    Microbial 1,2-dihydroxylation of sodium benzoate permits the rapid construction of novel inositol-amino acid hybrid structures. Both β- and γ-amino acids are accessible by means of an acylnitroso Diels-Alder cycloaddition. PMID:21409268

  18. 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.

  19. 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.

  20. Luminal Ca2+ promoting spontaneous Ca2+ release from inositol trisphosphate-sensitive stores in rat hepatocytes.

    PubMed Central

    Missiaen, L; Taylor, C W; Berridge, M J

    1992-01-01

    1. Spontaneous Ca2+ release from the inositol 1,4,5-trisphosphate (InsP3)-sensitive stores in permeabilized hepatocytes was monitored using Fluo-3 to measure the free [Ca2+] of the medium bathing the cells. 2. Permeabilized cells rapidly sequestered Ca2+, reducing the [Ca2+] to 103 +/- 5 nM. Under conditions that depended critically upon cell density and the amount of Ca2+ in the medium, this was followed by a slow increase in [Ca2+] culminating in a substantial Ca2+ spike representing synchronous discharge from the InsP3-sensitive stores. 3. During the latency preceding the Ca2+ spike, the stores increased their sensitivity to InsP3. This sensitization seemed to be an all-or-none phenomenon. 4. Oxidized glutathione and thimerosal promoted the spontaneous release by sensitizing the InsP3 receptor. 5. An increase in the [Ca2+] within the stores was required for both the increased sensitivity to InsP3 and the subsequent spike. 6. Caffeine (6 mM) antagonized the effect of very low InsP3 concentrations and abolished the Ca2+ spike, without itself releasing Ca2+. 7. Our results suggesting that luminal Ca2+ may sensitive InsP3-sensitive stores leading to spontaneous Ca2+ mobilization will be discussed in the light of a modified version of the two-pool model for explaining cytosolic Ca2+ oscillations. PMID:1484365

  1. 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.

  2. Adsorption of ruthenium red to phospholipid membranes.

    PubMed Central

    Voelker, D; Smejtek, P

    1996-01-01

    We have measured the distribution of the hexavalent ruthenium red cation (RuR) between water and phospholipid membranes, have shown the critical importance of membrane negative surface charge for RuR binding, and determined the association constant of RuR for different phospholipid bilayers. The studies were performed with liposomes made of mixtures of zwitterionic L-alpha-phosphatidylcholine (PC), and one of the negatively charged phospholipids: L-alpha-phosphatidylserine (PS), L-alpha-phosphatidylinositol (PI), or L-alpha-phosphatidylglycerol (PG). Lipid composition of PC:PX membranes was 1:0, 19:1, 9:1, and 4:1. Liposomes were processed using freeze-and-thaw treatment, and their size distribution was characterized by light scattering and electron microscopy. Experimental distribution isotherms of RuR obtained by ultracentrifugation and spectrophotometry can be reproduced with the Langmuir-Stern-Grahame model, assuming that RuR behaves in the diffuse double layer as an ion with effective valency < 6. In terms of this model, PC-PS, PC-PI, and PC-PG membranes were found to be electrostatically equivalent and the intrinsic association constants of RuR were obtained. RuR has highest affinity to PS-containing membranes; its association constant for PC-PI and PC-PG membranes is about 5 times smaller than that for PC-PS membranes. From the comparison of RuR binding to mixed negatively charged phospholipid membranes and RuR binding to sarcoplasmic reticulum (SR), we conclude that the low-affinity RuR binding sites may indeed be associated with the lipid bilayer of SR. PMID:8789099

  3. Enantiomers of myo-inositol-1,3,4-trisphosphate and myo-inositol-1,4,6 -trisphosphate: stereospecific recognition by cerebellar and platelet myo-inositol-1,4,5-trisphosphate receptors.

    PubMed

    Murphy, C T; Bullock, A J; Lindley, C J; Mills, S J; Riley, A M; Potter, B V; Westwick, J

    1996-11-01

    The naturally occurring tetrakisphosphate myo-inositol-1,3,4, 6-tetrakisphosphate [Ins(1,3,4,6)P4] was able to release Ca2+ from the intracellular stores of permeabilized rabbit platelets but was 40-fold less potent than D-myo-inositol-1,4,5-trisphosphate [Ins(1,4,5)P3]. The Ca2+ releasing activity of Ins(1,3,4,6)P4 was rationalized by envisaging two alternative receptor binding orientations in which the vicinal D-1,6-bisphosphate of Ins(1,3,4,6)P4 mimics the D-4,5-bisphosphate in the Ins(1,4,5)P3 binding conformation. This rationalization predicted that Ins(1,4,5)P3 regioisomers [i.e, D-myo-inositol -1,4,6-trisphosphate [D-Ins(1,4,6)P3] and D-myo-inositol-1,3,6 -trisphosphate [D-Ins(1,3,6)P3

  4. New compatible solutes related to Di-myo-inositol-phosphate in members of the order Thermotogales.

    PubMed Central

    Martins, L O; Carreto, L S; Da Costa, M S; Santos, H

    1996-01-01

    The accumulation of intracellular organic solutes was examined in six species of the order Thermotogales by nuclear magnetic resonance spectroscopy. The newly discovered compounds di-2-O-beta-mannosyl-di-myo-inositol-1,1'(3,3')-phosphate and di-myo-inositol-1,3'-phosphate were identified in Thermotoga maritima and Thermotoga neapolitana. In the latter species, at the optimum temperature and salinity the organic solute pool was composed of di-myo-inositol-1,1'(3,3')-phosphate, beta-glutamate, and alpha-glutamate in addition to di-myo-inositol-1,3'-phosphate and di-2-O-beta-mannosyl-di-myo-inositol-1,1'(3,3')-phosphate. The concentrations of the last two solutes increased dramatically at supraoptimal growth temperatures, whereas beta-glutamate increased mainly in response to a salinity stress. Nevertheless, di-myo-inositol-1,1'(3,3')-phosphate was the major compatible solute at salinities above the optimum for growth. The amino acids alpha-glutamate and proline were identified under optimum growth conditions in Thermosipho africanus, and beta-mannosylglycerate, trehalose, and glycine betaine were detected in Petrotoga miotherma. Organic solutes were not detected, under optimum growth conditions, in Thermotoga thermarum and Fervidobacterium islandicum, which have a low salt requirement or none. PMID:8824608

  5. Does myo-inositol effect on PCOS follicles involve cytoskeleton regulation?

    PubMed

    Bizzarri, Mariano; Cucina, Alessandra; Dinicola, Simona; Harrath, Abdel Halim; Alwasel, Saleh H; Unfer, Vittorio; Bevilacqua, Arturo

    2016-06-01

    Inositol metabolism is severely impaired in follicles obtained from cystic ovaries, leading to deregulated insulin transduction and steroid synthesis. On the contrary, inositol administration to women suffering from polycystic ovary syndrome (PCOS) has been proven to efficiently counteract most of the clinical hallmarks displayed by PCOS patients, including insulin resistance, hyperandrogenism and oligo-amenorrhea. We have recently observed that myo-inositol induces significant changes in cytoskeletal architecture of breast cancer cells, by modulating different biochemical pathways, eventually modulating the epithelial-mesenchymal transition. We hypothesize that inositol and its monophosphate derivatives, besides their effects on insulin transduction, may efficiently revert histological and functional features of cystic ovary by inducing cytoskeleton rearrangements. We propose an experimental model that could address not only whether inositol modulates cytoskeleton dynamics in both normal and cystic ovary cells, but also whether this effect may interfere with ovarian steroidogenesis. A more compelling understanding of the mechanisms of action of inositol (and its derivatives) would greatly improve its therapeutic utilization, by conferring to current treatments a well-grounded scientific rationale. PMID:27142131

  6. 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. PMID:15264889

  7. 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

  8. Purification, cloning and characterization of a GPI inositol deacylase from Trypanosoma brucei

    PubMed Central

    Güther, Maria Lucia Sampaio; Leal, Simone; Morrice, Nicholas A.; Cross, George A.M.; Ferguson, Michael A.J.

    2001-01-01

    Inositol acylation is an obligatory step in glycosylphosphatidylinositol (GPI) biosynthesis whereas mature GPI anchors often lack this modification. The GPI anchors of Trypanosoma brucei variant surface glycoproteins (VSGs) undergo rounds of inositol acylation and deacylation during GPI biosynthesis and the deacylation reactions are inhibited by diisopropylfluorophosphate (DFP). Inositol deacylase was affinity labelled with [3H]DFP and purified. Peptide sequencing was used to clone GPIdeAc, which encodes a protein with significant sequence and hydropathy similarity to mammalian acyloxyacyl hydrolase, an enzyme that removes fatty acids from bacterial lipopolysaccharide. Both contain a signal sequence followed by a saposin domain and a GDSL-lipase domain. GPIdeAc–/– trypanosomes were viable in vitro and in animals. Affinity-purified HA-tagged GPIdeAc was shown to have inositol deacylase activity. However, total inositol deacylase activity was only reduced in GPIdeAc–/– trypanosomes and the VSG GPI anchor was indistinguishable from wild type. These results suggest that there is redundancy in T.brucei inositol deacylase activity and that there is another enzyme whose sequence is not recognizably related to GPIdeAc. PMID:11532956

  9. Effects of inositol trisphosphate on calcium mobilization in high-voltage and saponin-permeabilized platelets

    SciTech Connect

    Gear, A.R.L.; Hallam, T.J.

    1986-03-01

    Interest in phosphatidylinositol metabolism has been greatly stimulated by the findings that diglyceride and inositol phosphates may serve as second messengers in modulating cellular function. Formation of 1,4,5-inositol trisphosphate (IP/sub 3/), in particular, has been linked to mobilization of intracellular calcium in a number of cell types. The authors have examined the ability of IP/sub 3/ to mobilize calcium in human platelets permeabilized by either saponin or high-voltage discharge. Saponin at 15 ..mu..g/ml effectively permeabilized platelets to exogenous inositol 1,4,5-trisphosphate which released bound (/sup 45/Ca) within 1 min and with a Ka of 7.4 +/- 4.1 ..mu..M. A small (25%) azide-sensitive pool was also responsive to inositol trisphosphate. The calcium pools were completely discharged by A-23187 and the ATP-dependent uptake was prevented by dinitrophenol. In contrast to the result with saponin, platelets accessed by high-voltage discharge were insensitive to challenge by inositol 1,4,5-trisphosphate. The data suggest that while inositol 1,4,5-trisphosphate can rapidly mobilize platelet calcium, the ability to demonstrate this depends on the method of permeabilization.

  10. Regulation of high molecular weight bovine brain neutral protease by phospholipids in vitro.

    PubMed

    Chauhan, V; Sheikh, A M; Chauhan, A; Spivack, W D; Fenko, M D; Malik, M N

    2005-04-01

    The activity of the heat stable, glycosylated high molecular weight bovine brain neutral protease (HMW protease) is differentially regulated by phospholipids. While phosphatidylcholine (PC), phosphatidylserine (PS) and phosphatidic acid (PA) had only marginal stimulatory effect (40-75%) on the activity of HMW protease, lysophoshatidylcholine (lysoPC) and lysophosphatidic acid (lysoPA) activated the enzyme by more than two-fold. Both lysoPC and lysoPA exhibited concentration-dependent saturation kinetics for the activation of HMW protease. Surprisingly, phosphoinositides (phosphatidylinositol, PI; phosphatidylinositol 4-phosphate, PIP; and phosphatidylinositol 4,5-bisphosphate, PIP2) modulated the activity of protease differently: activation of the enzyme was higher with PIP (90%) as compared to PI (21%), whereas PIP2 inhibited the enzyme (16%). The inhibition of the protease by PIP2 was concentration-dependent. During receptor-coupled cell activation, phospholipase A2 (PLA2) converts PC and PA to lysoPC and lysoPA, respectively; PI is converted to PIP2 by successive enzymatic phosphorylation by PI 4-kinase and PIP 5-kinase; and phospholipase C (PLC) degrades PIP2 to diacylglycerol and inositol 1,4,5-trisphosphate. Therefore, the data suggest that HMW protease may be coupled to cell signal transduction where PLA2, PI 4-kinase, PIP 5-kinase and PLC are involved. PMID:16010981

  11. Bolaamphiphiles Promote Phospholipid Translocation Across Vesicle Membranes

    PubMed Central

    Forbes, Christopher C.; DiVittorio, Kristy M.; Smith, Bradley D.

    2008-01-01

    A series of membrane-spanning bolaamphiphiles (molecules with two hydrophilic end-groups connected by a hydrophobic linker) were prepared by a modular synthetic method and evaluated for their abilities to affect the dynamics of a surrounding bilayer membrane. The goal was to determine if the bolaamphiphiles promote the translocation of phospholipids across vesicle membranes. The bolaamphiphiles were incorporated at low levels (up to 5 mol%) in vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Inward translocation assays were performed using fluorescent, NBD-labeled phospholipid probes with phosphocholine (PC) or phosphoglycerol (PG) head-groups. The membrane-spanning bolaamphiphiles promote the translocation of both phospholipid probes in the order PG > PC, while shorter bolaamphiphiles (structures that must adopt a U-shape and keep both end-groups in the same leaflet of the membrane), and regular amphiphiles with one hydrophilic end-group, are inactive. These results are an exception to the rule-of-thumb that membrane-spanning bolaamphiphiles are inherently membrane stabilizing molecules that inhibit all types of membrane transport. PMID:16834395

  12. Enzyme-assisted total synthesis of the optical antipodes D-myo-inositol 3,4,5-trisphosphate and D-myo-inositol 1,5, 6-trisphosphate: aspects of their structure-activity relationship to biologically active inositol phosphates.

    PubMed

    Adelt, S; Plettenburg, O; Stricker, R; Reiser, G; Altenbach, H J; Vogel, G

    1999-04-01

    Unambiguous total syntheses of both optical antipodes of the enantiomeric pair D-myo-inositol 3,4,5-trisphosphate (Ins(3,4,5)P3) and D-myo-inositol 1,5,6-trisphosphate (Ins(1,5,6)P3) are described. The ring system characteristic of myo-inositol was constructed de novo from p-benzoquinone. X-ray data for the enzymatically resolved (1S,2R,3R,4S)-1,4-diacetoxy-2,3-dibromocyclohex-5-ene enabled the unequivocal assignment of the absolute configuration. Subsequent transformations under stereocontrolled conditions led to enantiopure C2-symmetrical 1,4-(di-O-benzyldiphospho)conduritol B derivatives. Their synthetic potential was exploited to prepare Ins(3,4,5,6)P4 and Ins(1,4,5,6)P4 in three steps. With a recently identified and partially purified InsP5/InsP4 phosphohydrolase from Dictyostelium discoideum, these enantiomers could be converted to the target compounds, Ins(3,4,5)P3 and Ins(1,5,6)P3, on a preparative scale. An HPLC system employed for both purification of the inositol phosphates and analytical runs ensured that the products were isomerically homogeneous. The sensitivity of detection achieved by a complexometric postcolumn derivatization method indicates that the complexation properties of Ins(3,4,5)P3/Ins(1,5,6)P3 resemble those of Ins(1,2,3)P3, a compound with antioxidant potential. The set of inositol phosphates synthesized was used to clarify structural motifs important for molecular recognition by p42(IP4), a high-affinity Ins(1,3,4,5)P4/PtdIns(3,4,5)P3-specific binding protein from pig cerebellum. PMID:10197969

  13. 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.

  14. 10 CFR 205.11 - Order of precedence.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Order of precedence. 205.11 Section 205.11 Energy DEPARTMENT OF ENERGY OIL ADMINISTRATIVE PROCEDURES AND SANCTIONS General Provisions § 205.11 Order of precedence. (a) If there is any conflict or inconsistency between the provisions of this part and any...

  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 Clauses 3452.215-33 Order of precedence....

  16. 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...

  17. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) 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...

  18. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 8 2012-04-01 2012-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) 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...

  19. 26 CFR 1.665(e)-1 - Preceding taxable year.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false Preceding taxable year. 1.665(e)-1 Section 1.665... (CONTINUED) INCOME TAXES (CONTINUED) 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...

  20. The intracellular distribution of inositol polyphosphates in HL60 promyeloid cells.

    PubMed Central

    Stuart, J A; Anderson, K L; French, P J; Kirk, C J; Michell, R H

    1994-01-01

    1. HL60 promyeloid cells contain high intracellular concentrations of inositol polyphosphates, notably inositol 1,3,4,5,6-pentakisphosphate (InsP5) and inositol hexakisphosphate (InsP6). To determine their intracellular location(s), we studied the release of inositol (poly)phosphates, of ATP, and of cytosolic and granule-enclosed enzymes from cells permeabilized by four different methods. 2. When cells were treated with digitonin, all of the inositol phosphates were released in parallel with the cytosolic constituents. Most of the InsP5 and InsP6 was released before significant permeabilization of azurophil granules. 3. Similar results were obtained from cells preloaded with ethylene glycol and permeabilized by osmotic lysis. 4. Electroporation at approximately 500 V/cm caused rapid release of free inositol. Higher field strengths provoked release of most of the ATP, InsP5 and InsP6, but only slight release of the intracellular enzymes. Multiple discharges released approximately 80-90% of total InsP5 and InsP6. In the absence of bivalent-cation chelators, InsP5 and InsP6 were released less readily than ATP. 5. Treatment of cells with Staphylococcus aureus alpha-toxin caused quantitative release of inositol and ATP, without release of intracellular enzymes. However, inositol phosphates were released much less readily than inositol or ATP. Even after prolonged incubation with a high concentration of alpha-toxin, only approximately 50-70% of InsP2, InsP3 and InsP4 and < or = 20% of InsP5 and InsP6 were released, indicating that the high charge or large hydrated radius of InsP5 and InsP6 might limit their release through small toxin-induced pores. 6. These results indicate that most intracellular inositol metabolites are either in, or in rapid exchange with, the cytosolic compartment of HL60 cells. However, they leave open the possibility that a small proportion of cellular InsP5 and InsP6 (< or = 10-20%) might be in some intracellular bound form. Images Figure 2 PMID

  1. Prometabolites of 5-Diphospho-myo-inositol Pentakisphosphate.

    PubMed

    Pavlovic, Igor; Thakor, Divyeshsinh T; Bigler, Laurent; Wilson, Miranda S C; Laha, Debabrata; Schaaf, Gabriel; Saiardi, Adolfo; Jessen, Henning J

    2015-08-10

    Diphospho-myo-inositol phosphates (PP-InsP(y)) are an important class of cellular messengers. Thus far, no method for the transport of PP-InsP(y) into living cells is available. Owing to their high negative charge density, PP-InsP(y) will not cross the cell membrane. A strategy to circumvent this issue involves the generation of precursors in which the negative charges are masked with biolabile groups. A PP-InsP(y) prometabolite would require twelve to thirteen biolabile groups, which need to be cleaved by cellular enzymes to release the parent molecules. Such densely modified prometabolites of phosphate esters and anhydrides have never been reported to date. This study discloses the synthesis of such agents and an analysis of their metabolism in tissue homogenates by gel electrophoresis. The acetoxybenzyl-protected system is capable of releasing 5-PP-InsP5 in mammalian cell/tissue homogenates within a few minutes and can be used to release 5-PP-InsP5 inside cells. These molecules will serve as a platform for the development of fundamental tools required to study PP-InsP(y) physiology. PMID:26014370

  2. Intracellular calcium channels: inositol-1,4,5-trisphosphate receptors

    PubMed Central

    Fedorenko, Olena A.; Popugaeva, Elena; Enomoto, Masahiro; Stathopulos, Peter B.; Ikura, Mitsuhiko; Bezprozvanny, Ilya

    2014-01-01

    The inositol-1,4,5-trisphosphate receptors (InsP3Rs) are the major intracellular Ca2+-release channels in cells. Activity of InsP3Rs is essential for elementary and global Ca2+ events in the cell. There are three InsP3Rs isoforms that are present in mammalian cells. In this review review we will focus primarily on InsP3R type 1. The InsP3R1 is a predominant isoform in neurons and it is most extensively studied isoform. Combination of biophysical and structural methods revealed key mechanisms of InsP3R function and modulation. Cell biological and biochemical studies lead to identification of a large number of InsP3R-binding proteins. InsP3Rs are involved in the regulation of numerous physiological processes, including learning and memory, proliferation, differentiation, development and cell death. Malfunction of InsP3R1 play a role in a number of neurodegenerative disorders and other disease states. InsP3Rs represent a potentially valuable drug target for treatment of these disorders and for modulating activity of neurons and other cells. Future studies will provide better understanding of physiological functions of InsP3Rs in health and disease. PMID:24300389

  3. 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. PMID:27460418

  4. Enigmatic ion-exchange behavior of myo-inositol phosphates.

    PubMed

    Shelor, C Phillip; Liao, Hongzhu; Kadjo, Akinde Florence; Dasgupta, Purnendu K

    2015-05-01

    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. PMID:25865157

  5. A method for the modulation of membrane fluidity: homogeneous catalytic hydrogenation of phospholipids and phospholipids and phospholipid-water model biomembranes.

    PubMed Central

    Chapman, D; Quinn, P J

    1976-01-01

    The fatty acids associated with phospholipids of cell membranes, and particularly their degree of unsaturation, contribute to the fluidity of their structure and hance determine many of their biological properties. We describe a technique for modulating membrane fluidity which consists of hydrogenating the unsaturated double bonds of membrane phospholipids. This has been accomplished using a homogeneous catalyst. The process has been applied to phospholipids in organic solvents, to phospholipids dispersed as multibilayers in aqueous systems, and also to sonicated preparations of phospholipids arranged as single bilayer vesicles. Preliminary experiments have also been performed with biological membranes. These results indicate that the process of homogeneous catalysis for the modulation of lipid fluidity of biological cell membranes may have considerable future biological and biochemical application. PMID:1069280

  6. 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.

  7. PHOSPHOLIPIDS IN VEGETATIVE CELLS AND SPORES OF BACILLUS POLYMYXA1

    PubMed Central

    Matches, Jack R.; Walker, Homer W.; Ayres, John C.

    1964-01-01

    Matches, Jack R. (Iowa State University of Science and Technology, Ames), Homer W. Walker, and John C. Ayres. Phospholipids in vegetative cells and spores of Bacillus polymyxa. J. Bacteriol. 87:16–23. 1964.—The same types of phospholipids were recovered from both vegetative cells and spores of Bacillus polymyxa 1A39. Nitrogen-containing phospholipids were identified as phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, lysophosphatidyl serine, and lysolecithin. Acidic phosphatides containing no nitrogen were identified as phosphatidic acid, phosphatidyl glycerol, and a fraction appearing to be bis (phosphatidic) acid. The major phosphatide fraction in both cells and spores was phosphatidyl ethanolamine. Smaller amounts of phosphatidyl glycerol and bis (phosphatidic) acid were present; the other acidic phospholipid components were present only in trace amounts. Heat resistance of the spore as compared to the vegetative cell could not be attributed to a specific phospholipid, since no difference in the type of phospholipids present was observed. PMID:14102851

  8. Regiospecific phosphohydrolases from Dictyostelium as tools for the chemoenzymatic synthesis of the enantiomers D-myo-inositol 1,2,4-trisphosphate and D-myo-inositol 2,3,6-trisphosphate: non-physiological, potential analogues of biologically active D-myo-inositol 1,3,4-trisphosphate.

    PubMed

    Adelt, S; Plettenburg, O; Dallmann, G; Ritter, F P; Shears, S B; Altenbach, H J; Vogel, G

    2001-10-22

    A new de novo synthesis of the enantiomeric pair D-myo-inositol 1,2,4-trisphosphate and D-myo-inositol 2,3,6-trisphosphate is described. Starting from enantiopure dibromocyclohexenediol, several C2 symmetrical building blocks were synthesized which gave access to D-myo-inositol 1,2,4,5-tetrakisphosphate and D-myo-inositol 1,2,3,6-tetrakisphosphate. Exploiting the high regiospecificity of two partially purified phosphohydrolases from Dictyostelium, a 5-phosphatase and a phytase, the inositol tetrakisphosphates were converted enzymatically to the target compounds. Their potential to modulate the activity of Ins3,4,5,6P4 1-kinase was investigated and compared with the effects of D-myo-inositol 1,3,4-trisphosphate. PMID:11591506

  9. Critical assessment of phospholipid measurement in amniotic fluid.

    PubMed

    Badham, L P; Worth, H G

    1975-09-01

    We assessed several methods of inorganic phosphate assay for their suitability in estimating phospholipids in digested extracts of amniotic fluids. The extraction and digestion procedures used for phospholipids from amniotic fluid were also examined critically. The effect of contamination by blood or obstetric cream has been examined. Accordingly, we suggest a method for measuring total phospholipids in amniotic fluids, and results of it are compared with the lecithin/sphingomyelin ratio measurement in some clinical situations. PMID:1157310

  10. 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.

  11. Polyphosphoinositide binding domains: key to inositol lipid biology

    PubMed Central

    Hammond, Gerald R. V.; Balla, Tamas

    2014-01-01

    Polyphosphoinositides (PPIn) are an important family of phospholipids located on the cytoplasmic leaflet of eukaryotic cell membranes. Collectively, they are critical for the regulation 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. PMID:25732852

  12. Complexation studies on inositol-phosphates: IV. Ca(II) complexes of myo-inositol 1,4,5-trisphosphate.

    PubMed

    Schmitt, L; Schlewer, G; Spiess, B

    1992-01-01

    The stability constants of the complexes formed between Ca2+ and the myo-inositol 1,4,5-triphosphate (Ins(1,4,5)P3) were determined by potentiometric titration in two different media and temperature conditions (medium 1: I = 0.1 M But4NBr, 25 degrees C; medium 2: I = 0.2 M KCl, 37 degrees C). Mainly because of the presence of potassium the results obtained in these media show large differences in both the nature and the stability of the complexes. In medium 1, MH2L and M2L species are formed along with the ML and MHL species which also exist in medium 2. In addition, the stability of the latter species decreases by more than one log unit in going from medium 1 to medium 2. In an attempt to assess the biological significance of the metal binding to Ins(1,4,5)P3, the results were compared to the Ca2+-ATP complexes that form in the same media conditions. Taking into account the relative stability of the complexes of both systems, it is likely that the action or metabolism of Ins(1,4,5)P3 may be influenced by coordination of either alkali or alkali-earth cations. PMID:1588343

  13. 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. PMID:27370525

  14. Desensitization of prostaglandin F2 alpha-stimulated inositol phosphate generation in NIH-3T3 fibroblasts transformed by overexpression of normal c-Ha-ras-1, c-Ki-ras-2 and c-N-ras genes.

    PubMed Central

    Black, F M; Wakelam, M J

    1990-01-01

    The stimulation of inositol phosphate generation in control and ras-gene-transformed NIH-3T3 cells by prostaglandin F2 alpha (PGF2 alpha) was investigated. Compared with the control cells, a desensitization of the response was observed in cells transformed by the overexpression of N-, Ha-, or Ki-ras genes. This desensitization was without effect upon the concentration causing half-maximal effect (EC50), dissociation constant (Kd) or number of PGF2 alpha receptors. Inhibition of PG synthesis was without effect upon desensitization, demonstrating that the effect was not agonist-induced. Desensitization could be induced in NIH-3T3 cells by culturing under conditions where the cells were all in the exponential growth phase, or by a 12 h exposure to a C-kinase-activating phorbol ester. These results suggest that desensitization of certain agonist-induced inositol phospholipid responses in ras-transformed cells is a consequence of increased cell proliferation and associated amplification in C-kinase activity and is an indirect consequence of transformation by ras. PMID:2187437

  15. Inositol Metabolism in Plants. V. Conversion of Myo-inositol to Uronic Acid and Pentose Units of Acidic Polysaccharides in Root-tips of Zea mays 1

    PubMed Central

    Roberts, R. M.; Deshusses, J.; Loewus, F.

    1968-01-01

    The metabolism of myo-inositol-2-14C, d-glucuronate-1-14C, d-glucuronate-6-14C, and l-methionine-methyl-14C to cell wall polysaccharides was investigated in excised root-tips of 3 day old Zea mays seedlings. From myo-inositol, about one-half of incorporated label was recovered in ethanol insoluble residues. Of this label, about 90% was solubilized by treatment, first with a preparation of pectinase-EDTA, then with dilute hydrochloric acid. The only labeled constituents in these hydrolyzates were d-galacturonic acid, d-glucuronic acid, 4-O-methyl-d-glucuronic acid, d-xylose, and l-arabinose, or larger oligosaccharide fragments containing these units. Medium external to excised root-tips grown under sterile conditions in myo-inositol-2-14C contained labeled polysaccharide. When label was supplied in the form of d-glucuronate, the pattern of labeled uronic acid and pentose units in cell wall polysaccharides resembled that obtained from labeled myo-inositol, indicating that both substances were metabolized along a common path during polysaccharide formation, and that methylation occurred at a step subsequent to uronic acid formation. When label was supplied in the form of l-methionine-methyl-14C, 4-O-methyl-d-glucuronic acid was the only labeled monosaccharide component that survived enzymatic or acid hydrolysis. Zea mays endosperm, a known source of phytin, developed maximal phytase activity after the third day of germination. Results obtained here suggest that myo-inositol released by hydrolysis of phytin represents the initial precursor of a normal, possibly predominant pathway for the formation of uronic acids in plants. PMID:16656871

  16. Drug induced `softening' in phospholipid monolayers

    NASA Astrophysics Data System (ADS)

    Basak, Uttam Kumar; Datta, Alokmay; Bhattacharya, Dhananjay

    2015-06-01

    Compressibility measurements on Langmuir monolayers of the phospholipid Dimystoryl Phospatidylcholine (DMPC) in pristine form and in the presence of the Non-steroidal Anti-inflammatory Drug (NSAID) Piroxicam at 0.025 drug/lipid (D/L) molecular ratio at different temperatures, show that the monolayer exhibits large increase (and subsequent decrease) in compressibility due to the drug in the vicinity of the Liquid Expanded - Liquid Condensed (LE-LC) phase transition. Molecular dynamics simulations of the lipid monolayer in presence of drug molecules show a disordering of the tail tilt, which is consistent with the above result.

  17. 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%.

  18. 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. PMID:12697168

  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. Asymmetric distribution of glucose and indole-3-acetyl-myo-inositol in geostimulated Zea mays seedlings.

    PubMed

    Momonoki, Y S

    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. PMID:11537873

  2. Metabolism and Ovarian Function in PCOS Women: A Therapeutic Approach with Inositols.

    PubMed

    Laganà, Antonio Simone; Rossetti, Paola; Buscema, Massimo; La Vignera, Sandro; Condorelli, Rosita Angela; Gullo, Giuseppe; Granese, Roberta; 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

  3. Inositol lipid metabolism in vasopressin stimulated hepatocytes from rats infused with tumor necrosis factor

    SciTech Connect

    Spitzer, J.A.; Rodriguez de Turco, E.B. )

    1989-05-30

    We studied the effect of i.v. infusion of human recombinant tumor necrosis factor alpha (rHuTNF alpha, Cetus, 15 micrograms/100 g bw over 3 h) on vasopressin (VP)-stimulated {sup 32}P-inositol lipid turnover and the release of {sup 3}H-inositol phosphates in isolated rat hepatocytes. The early VP-induced decrease (within 30 s) in {sup 32}P-phosphatidylinositol 4-phosphate and {sup 32}P-phosphatidylinositol 4,5-bisphosphate labeling was significantly reduced (-40%) and at the same time the uptake of {sup 32}P into phosphatidic acid was 50% lower than in saline-infused (matched control) rats. Within 5 min of VP-stimulation, lower {sup 32}P phosphatidylinositol (-40%) and higher {sup 32}P-phosphatidic acid (+30%) labeling were observed in rHuTNF alpha-infused rats. Infusion of rHuTNF alpha also affected the VP-induced release of {sup 3}H-inositol phosphates. The accumulation of {sup 3}H-inositol-labeled water soluble products was decreased by 25% and 17% at 30 s and 10 min, respectively. These data show that rHuTNF alpha mimics early perturbations induced by Escherichia coli endotoxin infusion in VP-stimulated inositol lipid metabolism in rat hepatocytes.

  4. 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

  5. The aminosterol antibiotic squalamine permeabilizes large unilamellar phospholipid vesicles.

    PubMed

    Selinsky, B S; Zhou, Z; Fojtik, K G; Jones, S R; Dollahon, N R; Shinnar, A E

    1998-03-13

    The ability of the shark antimicrobial aminosterol squalamine to induce the leakage of polar fluorescent dyes from large unilamellar phospholipid vesicles (LUVs) has been measured. Micromolar squalamine causes leakage of carboxyfluorescein (CF) from vesicles prepared from the anionic phospholipids phosphatidylglycerol (PG), phosphatidylserine (PS), and cardiolipin. Binding analyses based on the leakage data show that squalamine has its highest affinity to phosphatidylglycerol membranes, followed by phosphatidylserine and cardiolipin membranes. Squalamine will also induce the leakage of CF from phosphatidylcholine (PC) LUVs at low phospholipid concentrations. At high phospholipid concentrations, the leakage of CF from PC LUVs deviates from a simple dose-response relationship, and it appears that some of the squalamine can no longer cause leakage. Fluorescent dye leakage generated by squalamine is graded, suggesting the formation of a discrete membrane pore rather than a generalized disruption of vesicular membranes. By using fluorescently labeled dextrans of different molecular weight, material with molecular weight /=10,000 is retained. Negative stain electron microscopy of squalamine-treated LUVs shows that squalamine decreases the average vesicular size in a concentration-dependent manner. Squalamine decreases the size of vesicles containing anionic phospholipid at a lower squalamine/lipid molar ratio than pure PC LUVs. In a centrifugation assay, squalamine solubilizes phospholipid, but only at significantly higher squalamine/phospholipid ratios than required for either dye leakage or vesicle size reduction. Squalamine solubilizes PC at lower squalamine/phospholipid ratios than PG. We suggest that squalamine complexes with phospholipid to form a discrete structure within the bilayers of LUVs, resulting in the transient leakage of small encapsulated molecules. At higher

  6. Phospholipid/aromatic thiol hybrid bilayers.

    PubMed

    Li, Chao; Wang, Mingming; Ferguson, Matthew; Zhan, Wei

    2015-05-12

    Gold-supported hybrid bilayers comprising phospholipids and alkanethiols have been found to be highly useful in biomembrane mimicking as well as biosensing ever since their introduction by Plant in 1993 (Plant, A. L. Langmuir 1993, 9, 2764-2767). Generalizing the mechanism (i.e., hydrophobic/hydrophobic interaction) that primarily drives bilayer formation, we report here that such a bilayer structure can also be successfully obtained when aromatic thiols are employed in place of alkanethiols. Four aromatic thiols were studied here (thiophenol, 2-naphthalene thiol, biphenyl-4-thiol, and diphenylenevinylene methanethiol), all affording reliable bilayer formation when 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes were incubated with self-assembled monolayers of these thiols. Characterization of the resultant structures, using cyclic voltammetry, impedance analysis, and atomic force microscopy, confirms the bilayer formation. Significant differences in electrochemical blocking and mechanical characteristics of these new bilayers were identified in comparison to their alkanethiol counterparts. Taking advantage of these new features, we present a new scheme for the straightforward biorecognition of a lipolytic enzyme (phospholipase A2) using these phospholipid/aromatic thiol bilayers. PMID:25896646

  7. Rapid Lateral Diffusion of Phospholipids in Rabbit Sarcoplasmic Reticulum

    PubMed Central

    Scandella, Carl J.; Devaux, Philippe; McConnell, Harden M.

    1972-01-01

    Phospholipid spin labels incorporated in the sarcoplasmic reticulum from rabbit-skeletal muscle undergo rapid lateral diffusion within the plane of the membrane. The diffusion constant, D, is 6×10-8 cm2/sec at 37°. With this diffusion constant, a phospholipid molecule can diffuse a distance of the order of 5000 nm in 1 sec. PMID:4506073

  8. 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. PMID:18054893

  9. Vasopressin induced production of inositol trisphosphate and calcium efflux in a smooth muscle cell line

    SciTech Connect

    Doyle, V.M.; Rueegg, U.T.

    1985-08-30

    Phosphatidylinositol metabolism and /sup 45/Ca/sup 2 +/ efflux were examined in a vascular smooth muscle cell line (A7r5). (Arg 8)Vasopressin stimulated the rapid formation (measurable at 1 sec) of inositol phosphates in a concentration-dependent manner. The time course for formation of inositol phosphates was similar to that for /sup 45/Ca/sup 2 +/ efflux from preloaded cells. The efflux of /sup 45/Ca/sup 2 +/ in response to (Arg8)vasopressin could be inhibited by a vasopressin antagonist. This supports the hypothesis that inositol 1,4,5-trisphosphate plays a role in vasopressin stimulated calcium mobilization from an intracellular source in cultured vascular smooth muscle cells.

  10. Inositol stimulates DNA and protein synthesis, and expansion by rabbit blastocysts in vitro.

    PubMed

    Fahy, M M; Kane, M T

    1992-04-01

    The effect of different concentrations (0, 0.6, 3, 15, 75 and 375 microM) of myo-inositol on the development of rabbit morulae to expanded blastocysts was investigated in terms of blastocyst expansion and synthesis of DNA and protein, as measured by incorporation of [3H]thymidine and [14C]amino acids into acid-precipitable material. A concentration of 15 microM inositol caused a 2.8-fold increase in blastocyst expansion (P less than 0.01), a 9.9-fold increase in thymidine incorporation into DNA (P less than 0.01) and a 3.6-fold increase in amino acid incorporation into protein (P less than 0.01). There were no significant differences in the range from 15 to 375 microM inositol. PMID:1522201

  11. Inositol polyphosphates are not increased by overexpression of Ins(1,4,5)P3 3-kinase but show cell-cycle dependent changes in growth factor-stimulated fibroblasts.

    PubMed Central

    Balla, T; Sim, S S; Baukal, A J; Rhee, S G; Catt, K J

    1994-01-01

    NIH 3T3 fibroblasts were stably transfected with rat brain inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) 3-kinase to explore the relationship between increased production of Ins(1,3,4,5)P4 and the formation of InsP5 and InsP6. Mass measurements of InsP5 and InsP6 revealed no significant difference between kinase- and vector-transfected fibroblasts. However, such 3-kinase-transfected cells, when labeled with [3H]inositol for 48-72 h, showed lower levels of [3H]InsP5 and [3H]InsP6, as well as [3H]Ins(1,3,4,6)P4 and D/L[3H]Ins(1,4,5,6)P4, than their vector-transfected counterparts. Because Ins(1,4,5)P3 3-kinase-transfected cells grew less rapidly than vector-transfected controls, we determined whether the synthesis of InsP5 and InsP6 was related to a specific phase of the cell cycle. When NIH 3T3 cells prelabeled with [3H]inositol were synchronized by serum deprivation followed by stimulation with platelet-derived growth factor (PDGF), the amounts of labeled InsP5 and InsP6 began to increase only after 12 h of stimulation, when cells entered the S-phase as indicated by increased [3H]thymidine incorporation. The enhanced synthesis of these inositol polyphosphates was preceded by an early increase in Ins(1,4,5)P3 and its metabolites that was no longer evident by the fifth hour of PDGF action. There was also a prominent and biphasic increase in the level of D/L-Ins(1,4,5,6)P4 with an early peak at approximately 3 h and a second rise that paralleled the increases in InsP5 and InsP6. These results indicate that the formation of highly phosphorylated inositols is not tightly coupled to the receptor-mediated formation of Ins(1,4,5)P3 and its metabolites but is mainly determined by other factors that operate at specific points of the cell cycle. PMID:8186462

  12. Regulation of lung surfactant phospholipid synthesis and metabolism.

    PubMed

    Goss, Victoria; Hunt, Alan N; Postle, Anthony D

    2013-02-01

    The alveolar type II epithelial (ATII) cell is highly specialised for the synthesis and storage, in intracellular lamellar bodies, of phospholipid destined for secretion as pulmonary surfactant into the alveolus. Regulation of the enzymology of surfactant phospholipid synthesis and metabolism has been extensively characterised at both molecular and functional levels, but understanding of surfactant phospholipid metabolism in vivo in either healthy or, especially, diseased lungs is still relatively poorly understood. This review will integrate recent advances in the enzymology of surfactant phospholipid metabolism with metabolic studies in vivo in both experimental animals and human subjects. It will highlight developments in the application of stable isotope-labelled precursor substrates and mass spectrometry to probe lung phospholipid metabolism in terms of individual molecular lipid species and identify areas where a more comprehensive metabolic model would have considerable potential for direct application to disease states. PMID:23200861

  13. Regulation of Phospholipid Synthesis in Escherichia coli by Guanosine Tetraphosphate

    PubMed Central

    Merlie, John P.; Pizer, Lewis I.

    1973-01-01

    Phospholipid synthesis has been reported to be subject to stringent control in Escherichia coli. We present evidence that demonstrates a strict correlation between guanosine tetraphosphate accumulation and inhibition of phospholipid synthesis. In vivo experiments designed to examine the pattern of phospholipid labeling with 32P-inorganic phosphate and 32P-sn-glycerol-3-phosphate suggest that regulation must occur at the glycerol-3-phosphate acyltransferase step. Assay of phospholipid synthesis by cell-free extracts and semipurified preparations revealed that guanosine tetraphosphate inhibits at least two enzymes specific for the biosynthetic pathway, sn-glycerol-3-phosphate acyltransferase as well as sn-glycerol-3-phosphate phosphatidyl transferase. These findings provide a biochemical basis for the stringent control of lipid synthesis as well as regulation of steady-state levels of phospholipid in growing cells. Images PMID:4583220

  14. Inositol Pentakisphosphate Isomers Bind PH Domains with Varying Specificity and Inhibit Phosphoinositide Interactions

    SciTech Connect

    S Jackson; S Al-Saigh; C Schultz; M Junop

    2011-12-31

    PH domains represent one of the most common domains in the human proteome. These domains are recognized as important mediators of protein-phosphoinositide and protein-protein interactions. Phosphoinositides are lipid components of the membrane that function as signaling molecules by targeting proteins to their sites of action. Phosphoinositide based signaling pathways govern a diverse range of important cellular processes including membrane remodeling, differentiation, proliferation and survival. Myo-Inositol phosphates are soluble signaling molecules that are structurally similar to the head groups of phosphoinositides. These molecules have been proposed to function, at least in part, by regulating PH domain-phosphoinositide interactions. Given the structural similarity of inositol phosphates we were interested in examining the specificity of PH domains towards the family of myo-inositol pentakisphosphate isomers. In work reported here we demonstrate that the C-terminal PH domain of pleckstrin possesses the specificity required to discriminate between different myo-inositol pentakisphosphate isomers. The structural basis for this specificity was determined using high-resolution crystal structures. Moreover, we show that while the PH domain of Grp1 does not possess this high degree of specificity, the PH domain of protein kinase B does. These results demonstrate that some PH domains possess enough specificity to discriminate between myo-inositol pentakisphosphate isomers allowing for these molecules to differentially regulate interactions with phosphoinositides. Furthermore, this work contributes to the growing body of evidence supporting myo-inositol phosphates as regulators of important PH domain-phosphoinositide interactions. Finally, in addition to expanding our knowledge of cellular signaling, these results provide a basis for developing tools to probe biological pathway.

  15. Low myo-inositol indicating astrocytic damage in a case series of neuromyelitis optica.

    PubMed

    Ciccarelli, Olga; Thomas, David L; De Vita, Enrico; Wheeler-Kingshott, Claudia A M; Kachramanoglou, Carolina; Kapoor, Raj; Leary, Siobhan; Matthews, Lucy; Palace, Jacqueline; Chard, Declan; Miller, David H; Toosy, Ahmed T; Thompson, Alan J

    2013-08-01

    Astrocytic necrosis is a prominent pathological feature of neuromyelitis optica (NMO) lesions and is clinically relevant. We report 5 NMO-related cases, all with longitudinally extensive lesions in the upper cervical cord, who underwent cervical cord (1) H-magnetic resonance spectroscopy. Lower myo-inositol/creatine values, suggesting astrocytic damage, were consistently found within the NMO lesions when compared with healthy controls and patients with multiple sclerosis (MS), who showed at least 1 demyelinating lesion at the same cord level. Therefore, the in vivo quantification of myo-inositol may distinguish NMO from MS. This is an important step toward developing imaging markers for clinical trials in NMO. PMID:23553900

  16. Anti-inflammatory Inositol Derivatives from the Whole Plant of Inula cappa.

    PubMed

    Wu, Jiewei; Tang, Chunping; Yao, Sheng; Zhang, Lei; Ke, Changqiang; Feng, Linyin; Lin, Ge; Ye, Yang

    2015-10-23

    Twelve new inositol derivatives, classified into myoinositol (1-6) and l-inositol (10-15) types, along with five known analogues were isolated from the whole plant of Inula cappa. The structures of the new compounds were established by extensive analysis of mass spectrometric and 1D and 2D NMR spectroscopic data. All the tested compounds showed anti-inflammatory activities against the production of NO in RAW264.7 macrophages stimulated by lipopolysaccharide, with IC50 values ranging from 7 to 23 μM. PMID:26444098

  17. Surface complexation modeling of inositol hexaphosphate sorption onto gibbsite.

    PubMed

    Ruyter-Hooley, Maika; Larsson, Anna-Carin; Johnson, Bruce B; Antzutkin, Oleg N; Angove, Michael J

    2015-02-15

    The sorption of Inositol hexaphosphate (IP6) onto gibbsite was investigated using a combination of adsorption experiments, (31)P solid-state MAS NMR spectroscopy, and surface complexation modeling. Adsorption experiments conducted at four temperatures showed that IP6 sorption decreased with increasing pH. At pH 6, IP6 sorption increased with increasing temperature, while at pH 10 sorption decreased as the temperature was raised. (31)P MAS NMR measurements at pH 3, 6, 9 and 11 produced spectra with broad resonance lines that could be de-convoluted with up to five resonances (+5, 0, -6, -13 and -21ppm). The chemical shifts suggest the sorption process involves a combination of both outer- and inner-sphere complexation and surface precipitation. Relative intensities of the observed resonances indicate that outer-sphere complexation is important in the sorption process at higher pH, while inner-sphere complexation and surface precipitation are dominant at lower pH. Using the adsorption and (31)P MAS NMR data, IP6 sorption to gibbsite was modeled with an extended constant capacitance model (ECCM). The adsorption reactions that best described the sorption of IP6 to gibbsite included two inner-sphere surface complexes and one outer-sphere complex: ≡AlOH + IP₆¹²⁻ + 5H⁺ ↔ ≡Al(IP₆H₄)⁷⁻ + H₂O, ≡3AlOH + IP₆¹²⁻ + 6H⁺ ↔ ≡Al₃(IP₆H₃)⁶⁻ + 3H₂O, ≡2AlOH + IP₆¹²⁻ + 4H⁺ ↔ (≡AlOH₂)₂²⁺(IP₆H₂)¹⁰⁻. The inner-sphere complex involving three surface sites may be considered to be equivalent to a surface precipitate. Thermodynamic parameters were obtained from equilibrium constants derived from surface complexation modeling. Enthalpies for the formation of inner-sphere surface complexes were endothermic, while the enthalpy for the outer-sphere complex was exothermic. The entropies for the proposed sorption reactions were large and positive suggesting that changes in solvation of species play a major role in driving

  18. The impact of phospholipids and phospholipid removal on bioanalytical method performance.

    PubMed

    Carmical, Jennifer; Brown, Stacy

    2016-05-01

    Phospholipids (PLs) are a component of cellmembranes, biological fluids and tissues. These compounds are problematic for the bioanalytical chemist, especially when PLs are not the analytes of interest. PL interference with bioanalysis highly impacts reverse-phase chromatographic methods coupled with mass spectrometric detection. Phospholipids are strongly retained on hydrophobic columns, and can cause significant ionization suppression in the mass spectrometer, as they outcompete analyte molecules for ionization. Strategies for improving analyte detection in the presence of PLs are reviewed, including in-analysis modifications and sample preparation strategies. Removal of interfering PLs prior to analysis seems to be most effective atmoderating thematrix effects fromthese endogenous cellular components, and has the potential to simplify chromatography and improve column lifetime. Products targeted at PL removal for sample pre-treatment, as well as products that combine multiplemodes of sample preparation (i.e. Hybrid SPE), show significant promise inmediating the effect on PL interference in bioanalysis. PMID:26773720

  19. 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

  20. Simulations of zwitterionic and anionic phospholipid monolayers.

    PubMed

    Kaznessis, Yiannis N; Kim, Sangtae; Larson, Ronald G

    2002-04-01

    Results of atomistic molecular dynamics simulations of dipalmitoylphosphatidylcholine and dipalmitoylphosphatidylglycerol monolayers at the air/water interface are presented. Dipalmitoylphosphatidylcholine is zwitterionic and dipalmitoylphosphatidylglycerol is anionic at physiological pH. NaCl and CaCl2 water subphases are simulated. The simulations are carried out at different surface densities, and a simulation cell geometry is chosen that greatly facilitates the investigation of phospholipid monolayer properties. Ensemble average monolayer properties calculated from simulation are in agreement with experimental measurements. The dependence of the properties of the monolayers on the surface density, the type of the headgroup, and the ionic environment are explained in terms of atomistically detailed pair distribution functions and electron density profiles, demonstrating the strength of simulations in investigating complex, multicomponent systems of biological importance. PMID:11916834

  1. 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.

  2. Development of an Immunoassay for the Kidney Specific Protein myo-Inositol Oxygenase, a Potential Biomarker of Acute Kidney Injury

    PubMed Central

    Gaut, Joseph P.; Crimmins, Dan L.; Ohlendorf, Matt F.; Lockwood, Christina M.; Griest, Terry A.; Brada, Nancy A.; Hoshi, Masato; Sato, Bryan; Hotchkiss, Richard S.; Jain, Sanjay; Ladenson, Jack H.

    2014-01-01

    Background Acute kidney injury (AKI) affects 45% of critically ill patients resulting in increased morbidity and mortality. The diagnostic standard, serum creatinine (SCr), is non-specific and may not increase until days after injury. There is significant need for a renal specific AKI biomarker detectable early enough that there would be a potential window for therapeutic intervention. In this study, we sought to identify a renal specific biomarker of AKI. Methods Gene expression data was analyzed from normal mouse tissues to identify kidney specific genes, one of which was Miox. Monoclonal antibodies were generated to recombinant myo-inositol oxygenase (MIOX), and an immunoassay was developed to quantify MIOX in plasma. The immunoassay was tested in animals and retrospectively in patients with and without AKI. Results Kidney tissue specificity of MIOX was supported by Western blot. Immunohistochemistry localized MIOX to the proximal renal tubule. Plasma MIOX, undetectable at baseline, increased 24 hours following AKI in mice. Plasma MIOX was increased in critically ill patients with AKI (12.4 ± 4.3 ng/mL, n=42) compared with patients without AKI (0.5 ± 0.3 ng/mL, n=17) and was highest in patients with oliguric AKI (20.2 ± 7.5 ng/mL, n=23). Plasma MIOX increased 54.3 ± 3.8 hours before the increase in SCr. Conclusions MIOX is a renal specific, proximal tubule protein that is increased in plasma of animals and critically ill patients with AKI. MIOX preceded the elevation in SCr by approximately two days in human patients. Large-scale studies are warranted to further investigate MIOX as an AKI biomarker. PMID:24486646

  3. Inositol 1,2,3-trisphosphate and inositol 1,2- and/or 2,3-bisphosphate are normal constituents of mammalian cells.

    PubMed Central

    Barker, C J; French, P J; Moore, A J; Nilsson, T; Berggren, P O; Bunce, C M; Kirk, C J; Michell, R H

    1995-01-01

    1. An inositol trisphosphate (InsP3) distinct from Ins(1,4,5)P3 and Ins(1,3,4)P3, which we previously observed in myeloid and lymphoid cells [French, Bunce, Stephens, Lord, McConnell, Brown, Creba and Michell (1991) Proc R. Soc. London B 245, 193-201; Bunce, French, Allen, Mountford, Moore, Greaves, Michell and Brown (1993) Biochem. J. 289, 667-673], is present in WRK1 rat mammary tumour cells and pancreatic endocrine beta-cells. 2. It has been identified as Ins(1,2,3)P3 by a combination of oxidation to ribitol, a structurally diagnostic polyol, and ammoniacal hydrolysis to identified inositol monophosphates. 3. Ins(1,2,3)P3 concentration in HL60 cells changed little during stimulation by ATP or fMetLeuPhe or during neutrophilic or monocytic differentiation, and Ins(1,2,3)P3 was unresponsive to vasopressin in WRK1 cells. 4. Ins(1,2,3)P3 was usually more abundant than Ins(1,4,5)P3, often being present at concentrations between approximately 1 microM and approximately 10 microM. 5. HL60, WRK-1 and lymphoid cells also contain Ins(1,2)P2 or Ins(2,3)P2, or a mixture of these two enantiomers, as a major InsP2 species. 6. Ins(1,2,3)P3 and Ins(1,2)P2/Ins(2,3)P2 are readily detected in cells labelled for long periods, but not in acutely labelled cells. This behaviour resembles that of InsP6, the most abundant cellular inositol polyphosphate that includes the 1,2,3-trisphosphate motif, which also achieves isotopic equilibrium with inositol only slowly. 7. Ins(1,2,3)P3 is the major InsP3 that accumulates during metabolism of InsP6 by WRK-1 cell homogenates. 8. Possible metabolic relationships between Ins(1,2,3)P3, Ins(1,2)P2/Ins(2,3)P2 and other inositol polyphosphates in cells, and a possible role for Ins(1,2,3)P3 in cellular iron handling, are considered. PMID:7887911

  4. Lactic Acid and Thermal Treatments Trigger the Hydrolysis of Myo-Inositol Hexakisphosphate and Modify the Abundance of Lower Myo-Inositol Phosphates in Barley (Hordeum vulgare L.)

    PubMed Central

    Metzler-Zebeli, Barbara U.; Deckardt, Kathrin; Schollenberger, Margit; Rodehutscord, Markus; Zebeli, Qendrim

    2014-01-01

    Barley is an important source of dietary minerals, but it also contains myo-inositol hexakisphosphate (InsP6) that lowers their absorption. This study evaluated the effects of increasing concentrations (0.5, 1, and 5%, vol/vol) of lactic acid (LA), without or with an additional thermal treatment at 55°C (LA-H), on InsP6 hydrolysis, formation of lower phosphorylated myo-inositol phosphates, and changes in chemical composition of barley grain. Increasing LA concentrations and thermal treatment linearly reduced (P<0.001) InsP6-phosphate (InsP6-P) by 0.5 to 1 g compared to the native barley. In particular, treating barley with 5% LA-H was the most efficient treatment to reduce the concentrations of InsP6-P, and stimulate the formation of lower phosphorylated myo-inositol phosphates such as myo-inositol tetraphosphate (InsP4) and myo-inositol pentaphosphates (InsP5). Also, LA and thermal treatment changed the abundance of InsP4 and InsP5 isomers with Ins(1,2,5,6)P4 and Ins(1,2,3,4,5)P5 as the dominating isomers with 5% LA, 1% LA-H and 5% LA-H treatment of barley, resembling to profiles found when microbial 6-phytase is applied. Treating barley with LA at room temperature (22°C) increased the concentration of resistant starch and dietary fiber but lowered those of total starch and crude ash. Interestingly, total phosphorus (P) was only reduced (P<0.05) in barley treated with LA-H but not after processing of barley with LA at room temperature. In conclusion, LA and LA-H treatment may be effective processing techniques to reduce InsP6 in cereals used in animal feeding with the highest degradation of InsP6 at 5% LA-H. Further in vivo studies are warranted to determine the actual intestinal P availability and to assess the impact of changes in nutrient composition of LA treated barley on animal performance. PMID:24967651

  5. Polysomnographic findings in nights preceding a migraine attack.

    PubMed

    Göder, R; Fritzer, G; Kapsokalyvas, A; Kropp, P; Niederberger, U; Strenge, H; Gerber, W D; Aldenhoff, J B

    2001-02-01

    Sleep recordings were performed in eight patients to analyse sleep alterations preceding migraine attacks. Polysomnographic recordings from nights before an attack were compared with nights without following migraine. We analysed standard sleep parameters and electroencephalogram (EEG) power spectra. The main findings preceding migraine attacks were a significant decrease in the number of arousals, a decrease in rapid eye movement (REM) density, a significant decrease of beta power in the slow wave sleep, and a decrease of alpha power during the first REM period. The results suggest a decrease in cortical activation during sleep preceding migraine attacks. According to the models of sleep regulation, alterations in the function of aminergic or cholinergic brainstem nuclei have to be discussed. PMID:11298661

  6. 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. PMID:27473012

  7. Production of glucaric acid from myo-inositol in engineered Pichia pastoris.

    PubMed

    Liu, Ye; Gong, Xu; Wang, Cui; Du, Guocheng; Chen, Jian; Kang, Zhen

    2016-09-01

    A potential myo-inositol oxygenase (ppMIOX) was identified as a functional enzyme and a glucaric acid synthetic pathway was firstly constructed in Pichia pastoris. Coexpression of the native ppMIOX and the urinate dehydrogenase (Udh) from Pseudomonas putida KT2440 led to obvious accumulation of glucaric acid (90.46±0.04mg/L) from myo-inositol whereas no glucaric acid was detected from glucose. In comparison, coexpression of the heterologous mouse MIOX (mMIOX) and Udh resulted in higher titers of glucaric acid from glucose and myo-inositol, 107.19±11.91mg/L and 785.4±1.41mg/L, respectively. By applying a fusion expression strategy with flexible peptides, the mMIOX specific activity and the glucaric acid concentration were significantly increased. Using glucose and myo-inositol as carbon substrates, the production of glucaric acid was substantially enhanced to 6.61±0.30g/L in fed-batch cultures. To the best of our knowledge, this is the highest reported value to date. PMID:27444324

  8. Muscarinic receptor-mediated inositol tetrakisphosphate response in bovine adrenal chromaffin cells

    SciTech Connect

    Sanborn, B.B.; Schneider, A.S. )

    1990-01-01

    Inositol trisphosphate (IP{sub 3}), a product of the phosphoinositide cycle, mobilizes intracellular Ca{sup 2+} in many cell types. New evidence suggests that inositol tetrakisphosphate (IP{sub 4}), an IP{sub 3} derivative, may act as another second messenger to further alter calcium homeostasis. However, the function and mechanism of action of IP{sub 4} are presently unresolved. We now report evidence of muscarinic receptor-mediated accumulation of IP{sub 4} in bovine adrenal chromaffin cells, a classic neurosecretory system in which calcium movements have been well studied. Muscarine stimulated an increase in ({sup 3}H)IP{sub 4} and ({sup 3}H)IP{sub 3} accumulation in chromaffin cells and this effect was completely blocked by atropine. ({sup 3}H)IP{sub 4} accumulation was detectable within 15 sec, increased to a maximum by 30 sec and thereafter declined. 2,3-diphosphoglycerate, an inhibitor of IP{sub 3} and IP{sub 4} hydrolysis, enhanced accumulation of these inositol polyphosphates. The results provide the first evidence of a rapid inositol tetrakisphosphate response in adrenal chromaffin cells, which should facilitate the future resolution of the relationship between IP{sub 4} and calcium homeostasis.

  9. Lipoarabinomannans: characterization of the multiacylated forms of the phosphatidyl-myo-inositol anchor by NMR spectroscopy.

    PubMed Central

    Nigou, J; Gilleron, M; Puzo, G

    1999-01-01

    Lipoarabinomannans, which exhibit a large spectrum of immunological activities, emerge as the major antigens of mycobacterial envelopes. The lipoarabinomannan structure is based on a phosphatidyl-myo-inositol anchor whose integrity has been shown to be crucial for lipoarabinomannan biological activity and particularly for presentation to CD4/CD8 double-negative alphabetaT cells by CD1 molecules. In this report, an analytical approach was developed for high-resolution 31P-NMR analysis of native, i.e. multiacylated, lipoarabinomannans. The one-dimensional 31P spectrum of cellular lipoarabinomannans, from Mycobacterium bovis Bacillus Calmette-Guérin, exhibited four 31P resonances typifying four types of lipoarabinomannans. Two-dimensional 1H-31P heteronuclear multiple-quantum-correlation/homonuclear Hartmann-Hahn analysis of the native molecules showed that these four types of lipoarabinomannan differed in the number and localization of fatty acids (from 1 to 4) esterifying the anchor. Besides the three acylation sites previously described, i.e. positions 1 and 2 of glycerol and 6 of the mannosyl unit linked to the C-2 of myo-inositol, we demonstrate the existence of a fourth acylation position at the C-3 of myo-inositol. We report here the first structural study of native multiacylated lipoarabinomannans, establishing the structure of the intact phosphatidyl-myo-inositol anchor. Our findings would help gain more understanding of the molecular basis of lipoarabinomannan discrimination in the binding process to CD1 molecules. PMID:9895288

  10. Blast neurotrauma impairs working memory and disrupts prefrontal myo-inositol levels in rats.

    PubMed

    Sajja, Venkata Siva Sai Sujith; Perrine, Shane A; Ghoddoussi, Farhad; Hall, Christina S; Galloway, Matthew P; VandeVord, Pamela J

    2014-03-01

    Working memory, which is dependent on higher-order executive function in the prefrontal cortex, is often disrupted in patients exposed to blast overpressure. In this study, we evaluated working memory and medial prefrontal neurochemical status in a rat model of blast neurotrauma. Adult male Sprague-Dawley rats were anesthetized with 3% isoflurane and exposed to calibrated blast overpressure (17 psi, 117 kPa) while sham animals received only anesthesia. Early neurochemical effects in the prefrontal cortex included a significant decrease in betaine (trimethylglycine) and an increase in GABA at 24 h, and significant increases in glycerophosphorylcholine, phosphorylethanolamine, as well as glutamate/creatine and lactate/creatine ratios at 48 h. Seven days after blast, only myo-inositol levels were altered showing a 15% increase. Compared to controls, short-term memory in the novel object recognition task was significantly impaired in animals exposed to blast overpressure. Working memory in control animals was negatively correlated with myo-inositol levels (r=-.759, p<0.05), an association that was absent in blast exposed animals. Increased myo-inositol may represent tardive glial scarring in the prefrontal cortex, a notion supported by GFAP changes in this region after blast overexposure as well as clinical reports of increased myo-inositol in disorders of memory. PMID:24534010

  11. MECHANISMS UNDERLYING ALC13 INHIBITION OF AGONIST-STIMULATED INOSITOL PHOSPHATE ACCUMULATION

    EPA Science Inventory

    Possible mechanisms of AlC13-induced inhibition of agonist-stimulated inositol phosphate (IP) accumulation were investigated using rat brain cortex slices, synaptosomes or homogenates. nder conditions in which AlC13 inhibits carbachol (CARB) stimulated IP accumulation (Gp-mediate...

  12. Extraction and analysis of inositols and other carbohydrates from soybean plant tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An outstanding characteristic of soybean plants is their ability to produce large amounts of the carbohydrate pinitol. Pinitol and the closely related inositols are currently undergoing widespread investigation for their biological and nutritional value. These and all the carbohydrates are typical...

  13. Barley (Hordeum vulgare L.) inositol monophosphatase: gene structure and enzyme characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The de novo synthesis of myo-inositol (Ins) is catalyzed by two enzymatic activities; Ins(3)P1 synthase (MIPS; EC. 5.5.1.4) and Ins monophosphatase (IMPase; EC 3.1.3.25). The barley IMP-1 gene and gene products were studied to facilitate research into the regulation of Ins synthesis and supply. In m...

  14. Genetic Control of Lithium Sensitivity and Regulation of Inositol Biosynthetic Genes

    PubMed Central

    King, Jason; Keim, Melanie; Teo, Regina; Weening, Karin E.; Kapur, Mridu; McQuillan, Karina; Ryves, Jonathan; Rogers, Ben; Dalton, Emma; Williams, Robin S. B.; Harwood, Adrian J.

    2010-01-01

    Lithium (Li+) is a common treatment for bipolar mood disorder, a major psychiatric illness with a lifetime prevalence of more than 1%. Risk of bipolar disorder is heavily influenced by genetic predisposition, but is a complex genetic trait and, to date, genetic studies have provided little insight into its molecular origins. An alternative approach is to investigate the genetics of Li+ sensitivity. Using the social amoeba Dictyostelium, we previously identified prolyl oligopeptidase (PO) as a modulator of Li+ sensitivity. In a link to the clinic, PO enzyme activity is altered in bipolar disorder patients. Further studies demonstrated that PO is a negative regulator of inositol(1,4,5)trisphosphate (IP3) synthesis, a Li+ sensitive intracellular signal. However, it was unclear how PO could influence either Li+ sensitivity or risk of bipolar disorder. Here we show that in both Dictyostelium and cultured human cells PO acts via Multiple Inositol Polyphosphate Phosphatase (Mipp1) to control gene expression. This reveals a novel, gene regulatory network that modulates inositol metabolism and Li+ sensitivity. Among its targets is the inositol monophosphatase gene IMPA2, which has also been associated with risk of bipolar disorder in some family studies, and our observations offer a cellular signalling pathway in which PO activity and IMPA2 gene expression converge. PMID:20567601

  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. Inositol deficiency increases the susceptibility to neural tube defects of genetically predisposed (curly tail) mouse embryos in vitro.

    PubMed

    Cockroft, D L; Brook, F A; Copp, A J

    1992-02-01

    Curly tail (ct/ct) mouse embryos, which have a genetic predisposition for neural tube defects (NTD), were grown in culture from the 2-5 somite stage, before the initiation of neurulation, up to the 22-24 somite stage, when closure of the anterior neural tube is normally complete. The embryos were cultured in whole rat serum or in extensively dialysed serum supplemented with glucose, amino acids, and vitamins, with inositol omitted or added at concentrations of 2, 10, 20, and 50 mg/l. Two strains were used as controls; CBA mice, which are related to curly tails, and an unrelated PO stock. It was found that ct/ct embryos were particularly sensitive to inositol deficiency; both they and the CBA embryos showed a similar high incidence of cranial NTD after culture in inositol deficient medium (12/17 and 11/18, respectively). Furthermore, the lowest dose of inositol had no effect on the frequency of head defects in ct/ct mice, though it halved the incidence in CBA embryos. With higher inositol concentrations, the majority of ct/ct embryos completed head closure normally, and their development was generally similar to that obtained in whole serum. PO embryos showed a lower proportion (5/19) of cranial NTD in the inositol deficient medium than the other two strains, and this was further reduced by even the lowest inositol dose. PMID:1615432

  17. GATA4-mediated cardiac hypertrophy induced by D-myo-inositol 1,4,5-tris-phosphate

    SciTech Connect

    Zhu Zhiming . E-mail: zhuzming@mail.dph-fsi.com; Zhu Shanjun; Liu Daoyan; Yu Zengping; Yang Yongjian; Giet, Markus van der; Tepel, Martin . E-mail: Martin.Tepel@charite.de

    2005-12-16

    We evaluated the effects of D-myo-inositol 1,4,5-tris-phosphate on cardiac hypertrophy. D-myo-inositol 1,4,5-tris-phosphate augmented cardiac hypertrophy as evidenced by its effects on DNA synthesis, protein synthesis, and expression of immediate-early genes c-myc and c-fos, {beta}-myosin heavy chain, and {alpha}-actin. The administration of D-myo-inositol 1,4,5-tris-phosphate increased the expression of nuclear factor of activated T-cells and cardiac-restricted zinc finger transcription factor (GATA4). Real-time quantitative RT-PCR showed that D-myo-inositol 1,4,5-tris-phosphate-induced GATA4 mRNA was significantly enhanced even in the presence of the calcineurin inhibitor, cyclosporine A. The effect of D-myo-inositol 1,4,5-tris-phosphate was blocked after inhibition of inositol-trisphosphate receptors but not after inhibition of c-Raf/mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (ERK) or p38 mitogen-activated protein kinase pathways. The study shows that D-myo-inositol 1,4,5-tris-phosphate-induced cardiac hypertrophy is mediated by GATA4 but independent from the calcineurin pathway.

  18. Formation and metabolism of inositol 1,4,5-trisphosphate in human platelets.

    PubMed Central

    Daniel, J L; Dangelmaier, C A; Smith, J B

    1987-01-01

    1. myo-[3H]Inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], when added to lysed platelets, was rapidly converted into [3H]inositol 1,3,4,5-tetrakisphosphate [Ins(1,3,4,5)P4], which was in turn converted into [3H]inositol 1,3,4-trisphosphate [Ins(1,3,4)P3]. This result demonstrates that platelets have the same metabolic pathways for interconversion of inositol polyphosphates that are found in other cells. 2. Labelling of platelets with [32P]Pi, followed by h.p.l.c., was used to measure thrombin-induced changes in the three inositol polyphosphates. Interfering compounds were removed by a combination of enzymic and non-enzymic techniques. 3. Ins(1,4,5)P3 was formed rapidly, and reached a maximum at about 4 s. It was also rapidly degraded, and was no longer detectable after 30-60 s. 4. Formation of Ins(1,3,4,5)P4 was almost as rapid as that of Ins(1,4,5)P3, and it remained detectable for a longer time. 5. Ins(1,3,4)P3 was formed after an initial lag, and this isomer reached its maximum, which was 10-fold higher than that of Ins(1,4,5)P3, at 30 s. 6. Comparison of the intracellular Ca2+ concentration as measured with fura-2 indicates that agents other than Ins(1,4,5)P3 are responsible for the sustained maintenance of a high concentration of intracellular Ca2+. It is proposed that either Ins(1,3,4)P3 or Ins(1,3,4,5)P4 may also be Ca2+-mobilizing agents. PMID:3499898

  19. PTH (parathyroid hormone) elevates inositol polyphosphates and diacylglycerol in a rat osteoblast-like cell line

    SciTech Connect

    Civitelli, R.; Reid, I.R.; Westbrook, S.; Avioli, L.V.; Hruska, K.A. )

    1988-11-01

    Parathyroid hormone (PTH)-stimulated signal transduction through mechanisms alternate to adenosine 3{prime},5{prime}-cyclic monophosphate (cAMP) production were studied in UMR 106-01 cells, a cell line with an osteoblastic phenotype. PTH produced transient, dose-related increases in cytosolic calcium ((Ca{sup 2+}){sub i}), inositol trisphosphates, and diacylglycerol (DAG). Both inositol 1,4,5-trisphosphate (Ins-1,4,5P{sub 3}) and inositol 1,3,4-trisphosphate (Ins-1,3,4P{sub 3}) production were rapidly stimulated by PTH. Consistent with the production of Ins-1,3,4P{sub 3}, rapid stimulation of late eluting inositol tetrakisphosphate was observed. The effects on the inositol phosphates were induced rapidly, consistent with roles as signals for changes in (Ca{sup 2+}){sub i}. In saponin-permeabilized UMR 106-01 cells, Ins-1,4,5P{sub 3} stimulated {sup 45}Ca release from a nonmitochondrial intracellular pool. Thus the hypothesis that PTH-stimulated Ins-1,4,5P{sub 3} production initiates Ca{sup 2+} release and contributes to transient elevations of (Ca{sup 2+}){sub i} is supported. These data suggest that stimulation of cAMP production during PTH stimulation may negatively affect production of rises in (Ca{sup 2+}){sub i} during PTH stimulation. The inactivation of the inhibitory G protein of adenylate cyclase by pertussis toxin could explain its action similar to cAMP analogues. Cyclci nucleotides diminish the effects of PTH on (Ca{sup 2+}){sub i}, probably interacting on a biochemical step subsequent to or independent of Ins-1,4,5P{sub 3} release.

  20. Sodium- and energy-dependent uptake of myo-inositol by rabbit peripheral nerve. Competitive inhibition by glucose and lack of an insulin effect.

    PubMed Central

    Greene, D A; Lattimer, S A

    1982-01-01

    Experimental diabetes consistently reduces the concentration of free myo-inositol in peripheral nerve, which usually exceeds that of plasma by 90-100-fold. This phenomenon has been explicitly linked to the impairment of nerve conduction in the acutely diabetic streptozocin-treated rat. However, the mechanism by which acute experimental diabetes lowers nerve myo-inositol content and presumably alters nerve myo-inositol content and presumably alters nerve myo-inositol metabolism is unknown. Therefore, the effects of insulin and elevated medium glucose concentration of 2-[3H]myo-inositol uptake were studied in a metabolically-defined in vitro peripheral nerve tissue preparation derived from rabbit sciatic nerve, whose free myo-inositol content is reduced by experimental diabetes. The results demonstrate that myo-inositol uptake occurs by at least two distinct transport systems in the normal endoneurial preparation. A sodium- and energy-dependent saturable transport system is responsible for at least 94% of the measured uptake at medium myo-inositol concentrations approximating that present in plasma. This carrier-mediated transport system has a high affinity for myo-inositol (Kt = 63 microM), and is not influenced acutely by physiological concentrations of insulin; it is, however, inhibited by hyperglycemic concentrations of glucose added to the incubation medium in a primarily competitive fashion. Thus, competitive inhibition of peripheral nerve myo-inositol uptake by glucose may constitute a mechanism by which diabetes produces physiologically significant alterations in peripheral nerve myo-inositol metabolism. PMID:6813354

  1. Discovery of carboxyethylpyrroles (CEPs): critical insights into AMD, autism, cancer, and wound healing from basic research on the chemistry of oxidized phospholipids.

    PubMed

    Salomon, Robert G; Hong, Li; Hollyfield, Joe G

    2011-11-21

    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

  2. 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.

  3. 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

    2015-01-01

    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. PMID:26212235

  4. p53 attenuates AKT signaling by modulating membrane phospholipid composition

    PubMed Central

    Rueda-Rincon, Natalia; Bloch, Katarzyna; Derua, Rita; Vyas, Rajesh; Harms, Amy; Hankemeier, Thomas; Khan, Niamat Ali; Dehairs, Jonas; Bagadi, Muralidhararao; Binda, Maria Mercedes; Waelkens, Etienne; Marine, Jean-Christophe; Swinnen, Johannes V.

    2015-01-01

    The p53 tumor suppressor is the central component of a complex network of signaling pathways that protect organisms against the propagation of cells carrying oncogenic mutations. Here we report a previously unrecognized role of p53 in membrane phospholipids composition. By repressing the expression of stearoyl-CoA desaturase 1, SCD, the enzyme that converts saturated to mono-unsaturated fatty acids, p53 causes a shift in the content of phospholipids with mono-unsaturated acyl chains towards more saturated phospholipid species, particularly of the phosphatidylinositol headgroup class. This shift affects levels of phosphatidylinositol phosphates, attenuates the oncogenic AKT pathway, and contributes to the p53-mediated control of cell survival. These findings expand the p53 network to phospholipid metabolism and uncover a new molecular pathway connecting p53 to AKT signaling. PMID:26061814

  5. Inhibition by calmodulin of calcium/phospholipid-dependent protein phosphorylation.

    PubMed Central

    Albert, K A; Wu, W C; Nairn, A C; Greengard, P

    1984-01-01

    Calmodulin was previously found to inhibit the Ca2+/phospholipid-dependent phosphorylation of an endogenous substrate, called the 87-kilodalton protein, in a crude extract prepared from rat brain synaptosomal cytosol. We investigated the mechanism of this inhibition, using Ca2+/phospholipid-dependent protein kinase and the 87-kilodalton protein, both of which had been purified to homogeneity from bovine brain. Rabbit brain calmodulin and some other Ca2+-binding proteins inhibited the phosphorylation of the 87-kilodalton protein by this kinase in the purified system. Calmodulin also inhibited the Ca2+/phospholipid-dependent phosphorylation of H1 histone, synapsin I, and the delta subunit of the acetylcholine receptor, with use of purified components. These results suggest that calmodulin may be a physiological regulator of Ca2+/phospholipid-dependent protein kinase. Images PMID:6233611

  6. 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

  7. The Role of Sexual Precedence in Verbal Sexual Coercion

    ERIC Educational Resources Information Center

    Livingston, Jennifer A.; Buddie, Amy M.; Testa, Maria; VanZile-Tamsen, Carol

    2004-01-01

    Experiences of verbal sexual coercion are common and have potential for negative consequences, yet are not well understood. This study used qualitative and descriptive statistics to examine verbal sexual coercion experiences among a community sample of 114 women and explored the role of sexual precedence in these experiences. Analyses revealed…

  8. Episodic Mood Changes Preceding an Exacerbation of Multiple Sclerosis

    PubMed Central

    Sharma, Priya; Morrow, Sarah A.; Owen, Richard J.

    2015-01-01

    Multiple sclerosis is a neurologic inflammatory disease that can manifest with psychiatric symptoms. Although depression is the most common psychiatric diagnosis in patients with multiple sclerosis, how depression develops is not fully understood. We present the case of an individual who displayed episodic mood changes preceding an exacerbation of multiple sclerosis symptoms. The clinical and research implications of this association are discussed. PMID:26835163

  9. Metrical expectations from preceding prosody influence perception of lexical stress.

    PubMed

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C; Tanenhaus, Michael K

    2015-04-01

    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 online probabilistic inferences about the sources of acoustic-phonetic variation during spoken-word recognition. PMID:25621583

  10. 48 CFR 819.202-72 - Order of precedence. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Order of precedence. 819.202-72 Section 819.202-72 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Policies 819.202-72 Order of...

  11. 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

  12. Counselor Interventions Preceding Client Laughter in Brief Therapy.

    ERIC Educational Resources Information Center

    Falk, Dana R.; Hill, Clara E.

    1992-01-01

    Examined whether 6 categories of counselor humor and 4 categories of risk interventions preceded client laughter in 236 events from 8 cases of brief psychotherapy. Found most client laughter was mild and moderate, with only eight instances of strong laughter. Humorous interventions led to more client laughter than did interventions that encouraged…

  13. Measurement of Phospholipids May Improve Diagnostic Accuracy in Ovarian Cancer

    PubMed Central

    Davis, Lorelei; Han, Gang; Zhu, Weiwei; Molina, Ashley D.; Arango, Hector; LaPolla, James P.; Hoffman, Mitchell S.; Sellers, Thomas; Kirby, Tyler; Nicosia, Santo V.; Sutphen, Rebecca

    2012-01-01

    Background More than two-thirds of women who undergo surgery for suspected ovarian neoplasm do not have cancer. Our previous results suggest phospholipids as potential biomarkers of ovarian cancer. In this study, we measured the serum levels of multiple phospholipids among women undergoing surgery for suspected ovarian cancer to identify biomarkers that better predict whether an ovarian mass is malignant. Methodology/Principal Findings We obtained serum samples preoperatively from women with suspected ovarian cancer enrolled through a prospective, population-based rapid ascertainment system. Samples were analyzed from all women in whom a diagnosis of epithelial ovarian cancer (EOC) was confirmed and from benign disease cases randomly selected from the remaining (non-EOC) samples. We measured biologically relevant phospholipids using liquid chromatography/electrospray ionization mass spectrometry. We applied a powerful statistical and machine learning approach, Hybrid huberized support vector machine (HH-SVM) to prioritize phospholipids to enter the biomarker models, and used cross-validation to obtain conservative estimates of classification error rates. Results The HH-SVM model using the measurements of specific combinations of phospholipids supplements clinical CA125 measurement and improves diagnostic accuracy. Specifically, the measurement of phospholipids improved sensitivity (identification of cases with preoperative CA125 levels below 35) among two types of cases in which CA125 performance is historically poor - early stage cases and those of mucinous histology. Measurement of phospholipids improved the identification of early stage cases from 65% (based on CA125) to 82%, and mucinous cases from 44% to 88%. Conclusions/Significance Levels of specific serum phospholipids differ between women with ovarian cancer and those with benign conditions. If validated by independent studies in the future, these biomarkers may serve as an adjunct at the time of clinical

  14. Effects of gamma irradiation on solid and lyophilised phospholipids

    NASA Astrophysics Data System (ADS)

    Stensrud, G.; Redford, K.; Smistad, G.; Karlsen, J.

    1999-11-01

    The effects of gamma irradiation (25 kGy) as a sterilisation method for phospholipids (distearoylphosphatidylcholine and distearoylphosphatidylglycerol) were investigated. 31P-NMR revealed minor chemical degradation of the phospholipids but lower dynamic viscosity and pseudoplasticity, lower turbidity, higher diffusion constant, smaller size, more negative zeta potential and changes in the phase transition behaviour of the subsequently produced liposomes were observed. The observed changes could to some extent be explained by the irradiation-induced degradation products (distearoylphosphatidic acid, fatty acids, lysophospholipids).

  15. Hyaluronan and phospholipid association in biolubrication.

    PubMed

    Wang, Min; Liu, Chao; Thormann, Esben; Dėdinaitė, Andra

    2013-12-01

    It is becoming increasingly clear that the outstanding lubrication of synovial joints is achieved by a sophisticated hierarchical structure of cartilage combined with synergistic actions of surface-active components present in the synovial fluid. In this work we focus on the association of two components of the synovial fluid, hyaluronan and dipalmitoyl phosphatidyl choline (DPPC), in bulk solution and at interfaces. We demonstrate that hyaluronan associates with DPPC vesicles and adsorbs to supported DPPC bilayers. The association structures formed at the interface are sufficiently stable to allow sequential adsorption of DPPC and hyaluronan, whereby promoting the formation of thick composite layers of these two components. The lubricating ability of such composite layers was probed by the AFM colloidal probe technique and found to be very favorable with low friction coefficients and high load bearing capacity. With DPPC as the last adsorbed component, a friction coefficient of 0.01 was found up to pressures significantly above what is encountered in healthy synovial joints. Hyaluronan as the last added component increases the friction coefficient to 0.03 and decreases the load bearing capacity somewhat (but still above what is needed in the synovial joint). Our data demonstrate that self-assembly structures formed by hyaluronan and phospholipids at interfaces are efficient aqueous lubricants, and it seems plausible that such self-assembly structures contribute to the exceptional lubrication of synovial joints. PMID:24171653

  16. 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. PMID:27050618

  17. Specific RNA binding to ordered phospholipid bilayers

    PubMed Central

    Janas, Tadeusz; Janas, Teresa; Yarus, Michael

    2006-01-01

    We have studied RNA binding to vesicles bounded by ordered and disordered phospholipid membranes. A positive correlation exists between bilayer order and RNA affinity. In particular, structure-dependent RNA binding appears for rafted (liquid-ordered) domains in sphingomyelin-cholesterol-1,2-dioleoyl-sn-glycero-3-phosphocholine vesicles. Binding to more highly ordered gel phase membranes is stronger, but much less RNA structure-dependent. All modes of RNA-membrane association seem to be electrostatic and headgroup directed. Fluorometry on 1,2-dimyristoyl-sn-glycero-3-phosphocholine liposomes indicates that bound RNA broadens the gel-fluid melting transition, and reduces lipid headgroup order, as detected via fluorometric measurement of intramembrane electric fields. RNA preference for rafted lipid was visualized and confirmed using multiple fluorophores that allow fluorescence and fluorescence resonance energy transfer microscopy on RNA molecules closely associated with ordered lipid patches within giant vesicles. Accordingly, both RNA structure and membrane order could modulate biological RNA–membrane interactions. PMID:16641318

  18. 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.

  19. 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.

  20. Effects of phospholipids on renal function.

    PubMed

    Buckalew, V M; Strandhoy, J W; Handa, R K

    1993-01-01

    The effects of two classes of phospholipids (PL) on renal function have been studied. Bolus injections of 1 ng (10 pmol) of lysophosphatidylcholine (LPC) caused natriuresis and diuresis in rats. Natriuretic activity was eliminated by substituting unsaturated bonds in the 1-acyl group and by removing the choline group on the sn-3 position. Natriuretic activity was not affected by substitution of 1-alkyl for 1-acyl groups. In the dog, LPC was natriuretic when given as a bolus of 3.0 micrograms/kg or as a constant infusion at 5 ng/kg/min. To explore further the effect of alkyl PLs on renal function, a series of studies with platelet activating factor (PAF) was performed. PAF injected directly into the renal artery (IR) in bolus doses of 0.5-10 ng/kg caused renal vasodilation that was blocked by a specific PAF receptor antagonist. This effect was not due to release of vasodilatory eicosanoids, dopamine, or nitric oxide (NO). PAF given IR as a continuous infusion at 2.5 ng/kg/min attenuated the renal vasoconstrictor effects of angiotensin II and norepinephrine but not vasopressin. This effect to attenuate vasoconstriction was blocked by the NO inhibitor N-monomethyl-L-arginine. These studies using picomolar amounts of PL suggest a physiologic role for these compounds in control of renal function. PMID:7508037

  1. 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.

  2. Lipid metabolizing enzyme activities modulated by phospholipid substrate lateral distribution.

    PubMed

    Salinas, Dino G; Reyes, Juan G; De la Fuente, Milton

    2011-09-01

    Biological membranes contain many domains enriched in phospholipid lipids and there is not yet clear explanation about how these domains can control the activity of phospholipid metabolizing enzymes. Here we used the surface dilution kinetic theory to derive general equations describing how complex substrate distributions affect the activity of enzymes following either the phospholipid binding kinetic model (which assumes that the enzyme molecules directly bind the phospholipid substrate molecules), or the surface-binding kinetic model (which assumes that the enzyme molecules bind to the membrane before binding the phospholipid substrate). Our results strongly suggest that, if the enzyme follows the phospholipid binding kinetic model, any substrate redistribution would increase the enzyme activity over than observed for a homogeneous distribution of substrate. Besides, enzymes following the surface-binding model would be independent of the substrate distribution. Given that the distribution of substrate in a population of micelles (each of them a lipid domain) should follow a Poisson law, we demonstrate that the general equations give an excellent fit to experimental data of lipases acting on micelles, providing reasonable values for kinetic parameters--without invoking special effects such as cooperative phenomena. Our theory will allow a better understanding of the cellular-metabolism control in membranes, as well as a more simple analysis of the mechanisms of membrane acting enzymes. PMID:21108012

  3. 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. PMID:25630300

  4. Mannose, glucosamine and inositol monophosphate inhibit the effects of insulin on lipogenesis. Further evidence for a role for inositol phosphate-oligosaccharides in insulin action.

    PubMed Central

    Machicao, F; Mushack, J; Seffer, E; Ermel, B; Häring, H U

    1990-01-01

    The mechanism of insulin signalling is not yet understood in detail. Recently, a role for inositol phosphate (IP)-oligosaccharides as second messengers transmitting the insulin signal at the post-kinase level was proposed. To evaluate this hypothesis further, we studied whether IP-oligosaccharides isolated from 'haemodialysate' have insulin-like activity. We found that these compounds mimic, in a dose-dependent fashion, the following effects of insulin in adipocytes. (1) Lipogenesis. Incorporation of [3H]glucose into lipids (expressed in nmol/min per 10(6) cells): basal, 0.74 +/- 0.05; insulin (1 mu unit/ml), 4.43 +/- 0.21; IP-oligosaccharide (2 micrograms/ml), 4.07 +/- 0.19. (2) Inhibition of isoprenaline (isoproterenol) (1 microM)-stimulated cyclic AMP levels and lipolysis. Cyclic AMP (pmol/10(5) cells): basal 0.84 +/- 0.05; isoprenaline, 4.03 +/- 0.19; isoprenaline + insulin (200 mu units/ml), 2.06 +/- 0.7; isoprenaline + IP-oligosaccharides (2 micrograms/ml), 2.4 +/- 0.29. Inhibition of lipolysis (mumol of glycerol/mg of protein): isoprenaline (1 microM), 166 +/- 11; isoprenaline+insulin (150 mu units/ml), 53 +/- 3.5; isoprenaline+IP-oligosaccharides (2 micrograms/ml), 58 +/- 5. (3) Stimulation of 3-O-methylglucose transport; basal, 9 +/- 3%; insulin (1 mu unit/ml), 67 +/- 4%, IP-oligosaccharides (2 micrograms/ml), 54 +/- 2%. To identify the active molecules of the IP-oligosaccharide fraction, competition experiments were performed. IP-oligosaccharide effects on lipogenesis were blocked by inositol monophosphate, glucosamine and mannose. In contrast, these compounds did not inhibit IP-oligosaccharide effects on membrane-mediated functions (3-O-methylglucose transport, cyclic AMP levels, lipolysis). We also found that the effect of insulin on lipogenesis was blocked by mannose, glucosamine and inositol monophosphate, whereas the insulin effects on 3-O-methylglucose, cyclic AMP and lipolysis were unaffected. The following conclusions were reached. (1) IP

  5. New insights into water-phospholipid model membrane interactions.

    PubMed

    Milhaud, Jeannine

    2004-05-27

    Modulating the relative humidity (RH) of the ambient gas phase of a phospholipid/water sample for modifying the activity of phospholipid-sorbed water [humidity-controlled osmotic stress methods, J. Chem. Phys. 92 (1990) 4519 and J. Phys. Chem. 96 (1992) 446] has opened a new field of research of paramount importance. New types of phase transitions, occurring at specific values of this activity, have been then disclosed. Hence, it is become recognized that this activity, like the temperature T, is an intensive parameter of the thermodynamical state of these samples. This state can be therefore changed (phase transition) either, by modulating T at a given water activity (a given hydration level), or, by modulating the water activity, at a given T. The underlying mechanisms of these two types of transition differ, especially when they appear as disorderings of fatty chains. In lyotropic transitions, this disordering follows from two thermodynamical laws. First, acting on the activity (the chemical potential) of water external to a phospholipid/water sample, a transbilayer gradient of water chemical potential is created, leading to a transbilayer flux of water (Fick's law). Second, water molecules present within the hydrocarbon region of this phospholipid bilayer interact with phospholipid molecules through their chemical potential (Gibbs-Duhem relation): the conformational state of fatty chains (the thermodynamical state of the phospholipid molecules) changes. This process is slow, as revealed by osmotic stress time-resolved experiments. In thermal chain-melting transitions, the first rapid step is the disordering of fatty chains of a fraction of phospholipid molecules. It occurs a few degrees before the main transition temperature, T(m), during the pretransition and the sub-main transition. The second step, less rapid, is the redistribution of water molecules between the different parts of the sample, as revealed by T-jump time-resolved experiments. Finally, in

  6. Phase behavior and permeability properties of phospholipid bilayers containing a short-chain phospholipid permeability enhancer.

    PubMed

    Risbo, J; Jørgensen, K; Sperotto, M M; Mouritsen, O G

    1997-10-01

    The thermodynamic phase behavior and trans-bilayer permeability properties of multilamellar phospholipid vesicles containing a short-chain DC10PC phospholipid permeability enhancer have been studied by means of differential scanning calorimetry and fluorescence spectroscopy. The calorimetric scans of DC14PC lipid bilayer vesicles incorporated with high concentrations of DC10PC demonstrate a distinct influence on the lipid bilayer thermodynamics manifested as a pronounced freezing-point depression and a narrow phase coexistence region. Increasing amounts of DC10PC lead to a progressive lowering of the melting enthalpy, implying a mixing behavior of the DC10PC in the bilayer matrix similar to that of a substitutional impurity. The phase behavior of the DC10PC-DC14PC mixture is supported by fluorescence polarization measurements which, furthermore, in the low-temperature gel phase reveal a non-monotonic concentration-dependent influence on the structural bilayer properties; small concentrations of DC10PC induce a disordering of the acyl chains, whereas higher concentrations lead to an ordering. Irreversible fluorescence quench measurements demonstrate a substantial increase in the trans-bilayer permeability over broad temperature and composition ranges. At temperatures corresponding to the peak positions of the heat capacity, a maximum in the trans-bilayer permeability is observed. The influence of DC10PC on the lipid bilayer thermodynamics and the associated permeability properties is discussed in terms of microscopic effects on the lateral lipid organization and heterogeneity of the bilayer. PMID:9370247

  7. Camptothecin-catalyzed phospholipid hydrolysis in liposomes.

    PubMed

    Saetern, Ann Mari; Skar, Merete; Braaten, Asmund; Brandl, Martin

    2005-01-01

    Hydrolysis of phospholipid (PL) within camptothecin (CPT)-containing liposomes was studied systematically, after elevated lyso-phosphatidylcholine (LPC)-concentrations in pH 5, CPT-containing liposomes (22.1+/-0.9 mol%) relative to control-liposomes (7.3+/-0.5 mol%) occasionally had been observed after four months storage in fridge. Liposomes were prepared by dispersing freeze-dried PL/CPT mixtures in 25 mM phosphate buffered saline (PBS) of varying pH (5.0-7.8) and CPT concentrations (0, 3 and 6 mM). PL-hydrolysis was monitored by HPTLC, quantifying LPC. In an accelerated stability study (60 degrees C), a catalytic effect of CPT on PL-hydrolysis was observed after 40 h, but not up to 30 h of incubation. The pH profile of the hydrolysis indicated a stability optimum at pH 6.0 for the liposomes independent of CPT. The equilibrium point between the more active lactone- and the carboxylate-form of CPT was found to be pH 6.8. As a compromise, pH 6.0 was chosen, assuring >85% CPT to be present in the lactone form. At this pH, both control- and CPT-liposomes showed only minor hydrolysis after autoclaving (121 degrees C, 15 min). Storage at room temperature and in fridge (2 months), as well as accelerated ageing (70 degrees C, 25 h), gave a significant elevation of LPC content in CPT-liposomes relative to control-liposomes. This study demonstrates a catalytic effect of CPT on PL-hydrolysis, the onset of which seems to require a certain threshold level of hydrolytic degradation. PMID:15607259

  8. The Charge Properties of Phospholipid Nanodiscs.

    PubMed

    Her, Cheng; Filoti, Dana I; McLean, Mark A; Sligar, Stephen G; Alexander Ross, J B; Steele, Harmen; Laue, Thomas M

    2016-09-01

    Phospholipids (PLs) are a major, diverse constituent of cell membranes. PL diversity arises from the nature of the fatty acid chains, as well as the headgroup structure. The headgroup charge is thought to contribute to both the strength and specificity of protein-membrane interactions. Because it has been difficult to measure membrane charge, ascertaining the role charge plays in these interactions has been challenging. Presented here are charge measurements on lipid Nanodiscs at 20°C in 100 mM NaCl, 50 mM Tris, at pH 7.4. Values are also reported for measurements made in the presence of Ca(2+) and Mg(2+) as a function of NaCl concentration, pH, and temperature, and in solvents containing other types of cations and anions. Measurements were made for neutral (phosphatidylcholine and phosphatidylethanolamine) and anionic (phosphatidylserine, phosphatidic acid, cardiolipin, and phosphatidylinositol 4,5-bisphosphate (PIP2)) PLs containing palmitoyl-oleoyl and dimyristoyl fatty acid chains. In addition, charge measurements were made on Nanodiscs containing an Escherichia coli lipid extract. The data collected reveal that 1) POPE is anionic and not neutral at pH 7.4; 2) high-anionic-content Nanodiscs exhibit polyelectrolyte behavior; 3) 3 mM Ca(2+) neutralizes a constant fraction of the charge, but not a constant amount of charge, for POPS and POPC Nanodiscs; 4) in contrast to some previous work, POPC only interacts weakly with Ca(2+); 5) divalent cations interact with lipids in a lipid- and ion-specific manner for POPA and PIP2 lipids; and 6) the monovalent anion type has little influence on the lipid charge. These results should help eliminate inconsistencies among data obtained using different techniques, membrane systems, and experimental conditions, and they provide foundational data for developing an accurate view of membranes and membrane-protein interactions. PMID:27602726

  9. Probing the promiscuous active site of myo-inositol dehydrogenase using synthetic substrates, homology modeling, and active site modification.

    PubMed

    Daniellou, Richard; Zheng, Hongyan; Langill, David M; Sanders, David A R; Palmer, David R J

    2007-06-26

    The active site of myo-inositol dehydrogenase (IDH, EC 1.1.1.18) from Bacillus subtilis recognizes a variety of mono- and disaccharides, as well as 1l-4-O-substituted inositol derivatives. It catalyzes the NAD+-dependent oxidation of the axial alcohol of these substrates with comparable kinetic constants. We have found that 4-O-p-toluenesulfonyl-myo-inositol does not act as a substrate for IDH, in contrast to structurally similar compounds such as those bearing substituted benzyl substituents in the same position. X-ray crystallographic analysis of 4-O-p-toluenesulfonyl-myo-inositol and 4-O-(2-naphthyl)methyl-myo-inositol, which is a substrate for IDH, shows a distinct difference in the preferred conformation of the aryl substituent. Conformational analysis of known substrates of IDH suggests that this conformational difference may account for the difference in reactivity of 4-O-p-toluenesulfonyl-myo-inositol in the presence of IDH. A sequence alignment of IDH with the homologous glucose-fructose oxidoreductase allowed the construction of an homology model of inositol dehydrogenase, to which NADH and 4-O-benzyl-scyllo-inosose were docked and the active site energy minimized. The active site model is consistent with all experimental results and suggests that a conserved tyrosine-glycine-tyrosine motif forms the hydrophobic pocket adjoining the site of inositol recognition. Y233F and Y235F retain activity, while Y233R and Y235R do not. A histidine-aspartate pair, H176 and D172, are proposed to act as a dyad in which H176 is the active site acid/base. The enzyme is inactivated by diethyl pyrocarbonate, and the mutants H176A and D172N show a marked loss of activity. Kinetic isotope effect experiments with D172N indicate that chemistry is rate-determining for this mutant. PMID:17539607

  10. A Role of Arabidopsis Inositol Polyphosphate Kinase, AtIPK2α, in Pollen Germination and Root Growth1

    PubMed Central

    Xu, Jun; Brearley, Charles A.; Lin, Wen-Hui; Wang, Yuan; Ye, Rui; Mueller-Roeber, Bernd; Xu, Zhi-Hong; Xue, Hong-Wei

    2005-01-01

    Inositol polyphosphates, such as inositol trisphosphate, are pivotal intracellular signaling molecules in eukaryotic cells. In higher plants the mechanism for the regulation of the type and the level of these signaling molecules is poorly understood. In this study we investigate the physiological function of an Arabidopsis (Arabidopsis thaliana) gene encoding inositol polyphosphate kinase (AtIPK2α), which phosphorylates inositol 1,4,5-trisphosphate successively at the D-6 and D-3 positions, and inositol 1,3,4,5-tetrakisphosphate at D-6, resulting in the generation of inositol 1,3,4,5,6-pentakisphosphate. Semiquantitative reverse transcription-PCR and promoter-β-glucuronidase reporter gene analyses showed that AtIPK2α is expressed in various tissues, including roots and root hairs, stem, leaf, pollen grains, pollen tubes, the flower stigma, and siliques. Transgenic Arabidopsis plants expressing the AtIPK2α antisense gene under its own promoter were generated. Analysis of several independent transformants exhibiting strong reduction in AtIPK2α transcript levels showed that both pollen germination and pollen tube growth were enhanced in the antisense lines compared to wild-type plants, especially in the presence of nonoptimal low Ca2+ concentrations in the culture medium. Furthermore, root growth and root hair development were also stimulated in the antisense lines, in the presence of elevated external Ca2+ concentration or upon the addition of EGTA. In addition, seed germination and early seedling growth was stimulated in the antisense lines. These observations suggest a general and important role of AtIPK2α, and hence inositol polyphosphate metabolism, in the regulation of plant growth most likely through the regulation of calcium signaling, consistent with the well-known function of inositol trisphosphate in the mobilization of intracellular calcium stores. PMID:15618435

  11. Osmoregulatory inositol transporter SMIT1 modulates electrical activity by adjusting PI(4,5)P2 levels.

    PubMed

    Dai, Gucan; Yu, Haijie; Kruse, Martin; Traynor-Kaplan, Alexis; Hille, Bertil

    2016-06-01

    Myo-inositol is an important cellular osmolyte in autoregulation of cell volume and fluid balance, particularly for mammalian brain and kidney cells. We find it also regulates excitability. Myo-inositol is the precursor of phosphoinositides, key signaling lipids including phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. However, whether myo-inositol accumulation during osmoregulation affects signaling and excitability has not been fully explored. We found that overexpression of the Na(+)/myo-inositol cotransporter (SMIT1) and myo-inositol supplementation enlarged intracellular PI(4,5)P2 pools, modulated several PI(4,5)P2-dependent ion channels including KCNQ2/3 channels, and attenuated the action potential firing of superior cervical ganglion neurons. Further experiments using the rapamycin-recruitable phosphatase Sac1 to hydrolyze PI(4)P and the P4M probe to visualize PI(4)P suggested that PI(4)P levels increased after myo-inositol supplementation with SMIT1 expression. Elevated relative levels of PIP and PIP2 were directly confirmed using mass spectrometry. Inositol trisphosphate production and release of calcium from intracellular stores also were augmented after myo-inositol supplementation. Finally, we found that treatment with a hypertonic solution mimicked the effect we observed with SMIT1 overexpression, whereas silencing tonicity-responsive enhancer binding protein prevented these effects. These results show that ion channel function and cellular excitability are under regulation by several "physiological" manipulations that alter the PI(4,5)P2 setpoint. We demonstrate a previously unrecognized linkage between extracellular osmotic changes and the electrical properties of excitable cells. PMID:27217553

  12. The RpiR-Like Repressor IolR Regulates Inositol Catabolism in Sinorhizobium meliloti▿†

    PubMed Central

    Kohler, Petra R. A.; Choong, Ee-Leng; Rossbach, Silvia

    2011-01-01

    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. PMID:21784930

  13. Determination of Myo-Inositol in Infant, Pediatric, and Adult Formulas by Liquid Chromatography-Pulsed Amperometric Detection with Column Switching: Collaborative Study, Final Action 2011.18.

    PubMed

    Butler-Thompson, Linda D; Jacobs, Wesley A; Schimpf, Karen J

    2015-01-01

    AOAC First Action Method 2011.18, Myo-Inositol (Free and Bound as Phosphatidylinositol) in Infant and Pediatric Formulas and Adult Nutritionals, was collaboratively studied. With this method free myo-inositol and phosphatidylinositol bound myo-inositol are extracted using two different sample preparation procedures, separated by ion chromatography using a combination of Dionex Carbo Pac PA1 and MA1 columns with column switching, and detected with pulsed amperometry using a gold electrode. Free myo-inositol is extracted from samples with dilute hydrochloric acid and water. Phosphatidylinositol is extracted from samples with chloroform and separated from other fats with silica SPE cartridges. Myo-inositol is then released from the glycerol backbone with concentrated acetic and hydrochloric acids at 120°C. During this collaborative study, nine laboratories from five different countries analyzed blind duplicates of nine infant and pediatric nutritional formulas for both free and phosphatidylinositol bound myo-inositol, and one additional laboratory only completed the free myo-inositol analyses. The method demonstrated acceptable repeatability and reproducibility and met the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Standard Method Performance Requirements (SMPRs®) for free myo-inositol plus phosphatidylinositol bound myo-inositol for all the matrixes analyzed. SMPRs for repeatability were ≤5% RSD at myo-inositol concentrations of 2-68 mg/100 g ready-to-feed (RTF) liquid. SMPRs for reproducibility were ≤8% RSD in products with myo-inositol concentrations ranging from 2 to 68 mg/100 g RTF liquid. During this collaborative study, repeatability RSDs ranged from 0.51 to 3.22%, and RSDs ranged from 2.66 to 7.55% for free myo-inositol plus phosphatidylinositol bound myo-inositol. PMID:26651580

  14. Extended precedence preservative crossover for job shop scheduling problems

    NASA Astrophysics Data System (ADS)

    Ong, Chung Sin; Moin, Noor Hasnah; Omar, Mohd

    2013-04-01

    Job shop scheduling problems (JSSP) is one of difficult combinatorial scheduling problems. A wide range of genetic algorithms based on the two parents crossover have been applied to solve the problem but multi parents (more than two parents) crossover in solving the JSSP is still lacking. This paper proposes the extended precedence preservative crossover (EPPX) which uses multi parents for recombination in the genetic algorithms. EPPX is a variation of the precedence preservative crossover (PPX) which is one of the crossovers that perform well to find the solutions for the JSSP. EPPX is based on a vector to determine the gene selected in recombination for the next generation. Legalization of children (offspring) can be eliminated due to the JSSP representation encoded by using permutation with repetition that guarantees the feasibility of chromosomes. The simulations are performed on a set of benchmarks from the literatures and the results are compared to ensure the sustainability of multi parents recombination in solving the JSSP.

  15. Binding of zinc and calcium to inositol phosphates (phytate) in vitro.

    PubMed

    Simpson, C J; Wise, A

    1990-07-01

    Inositol compounds with three to five phosphate groups (IP3-IP5) were produced by hydrolysis of phytate (inositol hexaphosphate, IP6) and their binding affinities for calcium and zinc investigated at neutral pH with relative concentrations that had been found in a range of students' meals. Zn solubility was negligible at many of these concentrations, with less Zn bound to precipitates of Ca-IP6 than Ca-IP5. The capacity to precipitate Zn at these ratios fell between IP5 and IP3. Zn was partially desorbed by soluble chelators (histidine and picolinate), especially when it had been adsorbed to preformed Ca-IP precipitates. A lower proportion of Zn was accessible to soluble chelators from Ca-IP4 than the other compounds. IP3-IP4 were hydrolysed by phytase more readily than IP5-IP6. PMID:2400762

  16. Huntington’s disease: Neural dysfunction linked to inositol polyphosphate multikinase

    PubMed Central

    Ahmed, Ishrat; Sbodio, Juan I.; Harraz, Maged M.; Tyagi, Richa; Grima, Jonathan C.; Albacarys, Lauren K.; Hubbi, Maimon E.; Xu, Risheng; Kim, Seyun; Paul, Bindu D.; Snyder, Solomon H.

    2015-01-01

    Huntington’s disease (HD) is a progressive neurodegenerative disease caused by a glutamine repeat expansion in mutant huntingtin (mHtt). Despite the known genetic cause of HD, the pathophysiology of this disease remains to be elucidated. Inositol polyphosphate multikinase (IPMK) is an enzyme that displays soluble inositol phosphate kinase activity, lipid kinase activity, and various noncatalytic interactions. We report a severe loss of IPMK in the striatum of HD patients and in several cellular and animal models of the disease. This depletion reflects mHtt-induced impairment of COUP-TF-interacting protein 2 (Ctip2), a striatal-enriched transcription factor for IPMK, as well as alterations in IPMK protein stability. IPMK overexpression reverses the metabolic activity deficit in a cell model of HD. IPMK depletion appears to mediate neural dysfunction, because intrastriatal delivery of IPMK abates the progression of motor abnormalities and rescues striatal pathology in transgenic murine models of HD. PMID:26195796

  17. Purification, crystallization and preliminary X-ray analysis of inositol dehydrogenase (IDH) from Bacillus subtilis

    SciTech Connect

    Van Straaten, K. E.; Hoffort, A.; Palmer, D. R. J.; Sanders, D. A. R.

    2008-02-01

    Selenomethionine-substituted IDH was crystallized using the microbatch method. The crystals diffracted to beyond 2.0 Å resolution using synchrotron radiation. Inositol dehydrogenase (IDH) is an enzyme that catalyses the NAD{sup +}-dependent oxidation of myo-inositol to scyllo-inosose. The enzyme has been purified to homogeneity by means of Ni{sup 2+}-affinity chromatography and was crystallized in both native and selenomethionine (SeMet) labelled forms using the microbatch method. SAD X-ray diffraction data were collected to 2.0 Å resolution from a SeMet-labelled crystal at the Advanced Photon Source (APS) and a MAD data set was collected to 1.75 Å resolution at the Canadian Light Source (CLS); this is the first reported anomalous diffraction experiment from the CLS. The crystals belong to space group I222 and contain one molecule per asymmetric unit.

  18. Modulation of HIV-like particle assembly in vitro by inositol phosphates

    PubMed Central

    Campbell, Stephen; Fisher, Robert J.; Towler, Eric M.; Fox, Stephen; Issaq, Haleem J.; Wolfe, Tracy; Phillips, Lawrence R.; Rein, Alan

    2001-01-01

    HIV-1 Gag protein assembles into 100- to 120-nm diameter particles in mammalian cells. Recombinant HIV-1 Gag protein assembles in a fully defined system in vitro into particles that are only 25–30 nm in diameter and that differ significantly in other respects from authentic particles. However, particles with the size and other properties of authentic virions were obtained in vitro by addition of inositol phosphates or phosphatidylinsitol phosphates to the assembly system. Thus, the interactions between HIV-1 Gag protein molecules are altered by binding of inositol derivatives; this binding is apparently essential for normal HIV-1 particle assembly. This requirement is not seen in a deleted Gag protein lacking residues 16–99 within the matrix domain. PMID:11526217

  19. Endogenous lipoid pneumonia preceding diagnosis of pulmonary alveolar proteinosis.

    PubMed

    Antoon, James W; Hernandez, Michelle L; Roehrs, Phillip A; Noah, Terry L; Leigh, Margaret W; Byerley, Julie S

    2016-03-01

    Pulmonary alveolar proteinosis (PAP) is an under-reported and under-diagnosed condition, with a high percentage of cases found on autopsy or late stage disease. The etiology of PAP includes genetic, primary (anti-granulocyte-macrophage colony-stimulating factor antibodies) and secondary (oncologic, rheumatologic, infectious, chemical and immunologic) causes. Here, we present the first reported pediatric case of endogenous lipoid pneumonia and non-specific interstitial pneumonitis preceding the development of PAP. PMID:25103284

  20. Characterization of a ligand-gated cation channel based on an inositol receptor in the silkworm, Bombyx mori.

    PubMed

    Kikuta, Shingo; Endo, Haruka; Tomita, Natsuo; Takada, Tomoyuki; Morita, Chiharu; Asaoka, Kiyoshi; Sato, Ryoichi

    2016-07-01

    Insect herbivores recognize non-volatile compounds in plants to direct their feeding behavior. Gustatory receptors (Gr) appear to be required for nutrient recognition by gustatory organs in the mouthparts of insects. Gr10 is expressed in Bombyx mori (BmGr10) mouthparts such as maxillary galea, maxillary palp, and labrum. BmGr10 is predicted to function in sugar recognition; however, the precise biochemical function remains obscure. Larvae of B. mori are monophagous feeders able to find and feed on mulberry leaves. Soluble mulberry leaf extract contains sucrose, glucose, fructose, and myo-inositol. In this study, we identified BmGr10 as an inositol receptor using electrophysiological analysis with the Xenopus oocyte expression system and Ca(2+) imaging techniques using mammalian cells. These results demonstrated that Xenopus oocytes or HEK293T cells expressing BmGr10 specifically respond to myo-inositol and epi-inositol but do not respond to any mono-, di-, or tri-saccharides or to some sugar alcohols. These inositols caused Ca(2+) and Na(+) influxes into the cytoplasm independently of a G protein-mediated signaling cascade, indicating that BmGr10 is a ligand-gated cation channel. Overall, BmGr10 plays an important role in the myo-inositol recognition required for B. mori larval feeding behavior. PMID:27132146

  1. Pharmacokinetics and Safety of a Single Intravenous Dose of myo-Inositol in Preterm Infants of 23 to 29 weeks

    PubMed Central

    Phelps, Dale L.; Ward, Robert M.; Williams, Rick L.; Watterberg, Kristi L.; Laptook, Abbot R.; Wrage, Lisa A.; Nolen, Tracy L.; Fennell, Timothy R.; Ehrenkranz, Richard A.; Poindexter, Brenda B.; Cotten, C. Michael; Hallman, Mikko K.; Frantz, Ivan D.; Faix, Roger G.; Zaterka-Baxter, Kristin M.; Das, Abhik; Ball, M. Bethany; O’Shea, T. Michael; Lacy, Conra Backstrom; Walsh, Michele C.; Shankaran, Seetha; Sánchez, Pablo J.; Bell, Edward F.; Higgins, Rosemary D.

    2014-01-01

    Background Myo-inositol given to preterm infants with respiratory distress has reduced death, increased survival without bronchopulmonary dysplasia (BPD) and reduced severe retinopathy of prematurity (ROP) in 2 randomized trials. Pharmacokinetic (PK) studies in extremely preterm infants are needed prior to efficacy trials. Methods Infants of 23–29 weeks gestation were randomized to a single intravenous (IV) dose of inositol at 60 or 120 mg/kg or placebo. Over 96 h, serum levels (sparse sampling population PK) and urine inositol excretion were determined. Population PK models were fit using a nonlinear mixed effects approach. Safety outcomes were recorded. Results A 1-compartment model that included factors for endogenous inositol production, allometric size based on weight, gestational age (GA) strata and creatinine clearance fit the data best. The central volume of distribution was 0.5115 l/kg, the clearance 0.0679 l/kg/h, endogenous production 2.67 mg/kg/h and the half life 5.22 h when modeled without the covariates. During the first 12 h renal inositol excretion quadrupled in the 120 mg/kg group, returning to near baseline after 48 h. There was no diuretic side-effect. No significant differences in adverse events occurred between the 3 groups (p > 0.05). Conclusions A single compartment model accounting for endogenous production satisfactorily described the PK of IV inositol. PMID:24067395

  2. Efficacy of IP6 + inositol in the treatment of breast cancer patients receiving chemotherapy: prospective, randomized, pilot clinical study

    PubMed Central

    2010-01-01

    Background Prospective, randomized, pilot clinical study was conducted to evaluate the beneficial effects of inositol hexaphosphate (IP6) + Inositol in breast cancer patients treated with adjuvant therapy. Patients and methods Patients with invasive ductal breast cancer where polychemotherapy was indicated were monitored in the period from 2005-2007. Fourteen patients in the same stage of ductal invasive breast cancer were involved in the study, divided in two randomized groups. One group was subjected to take IP6 + Inositol while the other group was taking placebo. In both groups of patients the same laboratory parameters were monitored. When the treatment was finished, all patients have filled questionnaires QLQ C30 and QLQ-BR23 to determine the quality of life. Results Patients receiving chemotherapy, along with IP6 + Inositol did not have cytopenia, drop in leukocyte and platelet counts. Red blood cell counts and tumor markers were unaltered in both groups. However, patients who took IP6 + Inositol had significantly better quality of life (p = 0.05) and functional status (p = 0.0003) and were able to perform their daily activities. Conclusion IP6 + Inositol as an adjunctive therapy is valuable help in ameliorating the side effects and preserving quality of life among the patients treated with chemotherapy. PMID:20152024

  3. Reduced myo-inositol and total choline measured with cerebral MRS in acute thyrotoxic Graves' disease.

    PubMed

    Elberling, T V; Danielsen, E R; Rasmussen, A K; Feldt-Rasmussen, U; Waldemar, G; Thomsen, C

    2003-01-14

    Neuropsychiatric symptoms in the acute thyrotoxic phase of Graves' disease suggest involvement of brain processes. Short-echo-time proton MRS was used to measure the cerebral metabolite profile in newly diagnosed and untreated Graves' disease. Sixteen patients with Graves' disease and 18 age- and sex-matched healthy volunteers were studied. The patients had significantly reduced total choline and myo-inositol in the acute phase of Graves' thyrotoxicosis compared with the healthy volunteers. PMID:12525741

  4. An Uncharacterized Member of the Ribokinase Family in Thermococcus kodakarensis Exhibits myo-Inositol Kinase Activity*

    PubMed Central

    Sato, Takaaki; Fujihashi, Masahiro; Miyamoto, Yukika; Kuwata, Keiko; Kusaka, Eriko; Fujita, Haruo; Miki, Kunio; Atomi, Haruyuki

    2013-01-01

    Here we performed structural and biochemical analyses on the TK2285 gene product, an uncharacterized protein annotated as a member of the ribokinase family, from the hyperthermophilic archaeon Thermococcus kodakarensis. The three-dimensional structure of the TK2285 protein resembled those of previously characterized members of the ribokinase family including ribokinase, adenosine kinase, and phosphofructokinase. Conserved residues characteristic of this protein family were located in a cleft of the TK2285 protein as in other members whose structures have been determined. We thus examined the kinase activity of the TK2285 protein toward various sugars recognized by well characterized ribokinase family members. Although activity with sugar phosphates and nucleosides was not detected, kinase activity was observed toward d-allose, d-lyxose, d-tagatose, d-talose, d-xylose, and d-xylulose. Kinetic analyses with the six sugar substrates revealed high Km values, suggesting that they were not the true physiological substrates. By examining activity toward amino sugars, sugar alcohols, and disaccharides, we found that the TK2285 protein exhibited prominent kinase activity toward myo-inositol. Kinetic analyses with myo-inositol revealed a greater kcat and much lower Km value than those obtained with the monosaccharides, resulting in over a 2,000-fold increase in kcat/Km values. TK2285 homologs are distributed among members of Thermococcales, and in most species, the gene is positioned close to a myo-inositol monophosphate synthase gene. Our results suggest the presence of a novel subfamily of the ribokinase family whose members are present in Archaea and recognize myo-inositol as a substrate. PMID:23737529

  5. Conformational Changes in Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase upon Substrate Binding

    PubMed Central

    Baños-Sanz, José Ignacio; Sanz-Aparicio, Julia; Whitfield, Hayley; Hamilton, Chris; Brearley, Charles A.; González, Beatriz

    2012-01-01

    Inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IP5 2-K) catalyzes the synthesis of inositol 1,2,3,4,5,6-hexakisphosphate from ATP and IP5. Inositol 1,2,3,4,5,6-hexakisphosphate is implicated in crucial processes such as mRNA export, DNA editing, and phosphorus storage in plants. We previously solved the first structure of an IP5 2-K, which shed light on aspects of substrate recognition. However, failure of IP5 2-K to crystallize in the absence of inositide prompted us to study putative conformational changes upon substrate binding. We have made mutations to residues on a region of the protein that produces a clasp over the active site. A W129A mutant allowed us to capture IP5 2-K in its different conformations by crystallography. Thus, the IP5 2-K apo-form structure displays an open conformation, whereas the nucleotide-bound form shows a half-closed conformation, in contrast to the inositide-bound form obtained previously in a closed conformation. Both nucleotide and inositide binding produce large conformational changes that can be understood as two rigid domain movements, although local changes were also observed. Changes in intrinsic fluorescence upon nucleotide and inositide binding are in agreement with the crystallographic findings. Our work suggests that the clasp might be involved in enzyme kinetics, with the N-terminal lobe being essential for inositide binding and subsequent conformational changes. We also show how IP5 2-K discriminates between inositol 1,3,4,5-tetrakisphosphate and 3,4,5,6-tetrakisphosphate enantiomers and that substrate preference can be manipulated by Arg130 mutation. Altogether, these results provide a framework for rational design of specific inhibitors with potential applications as biological tools for in vivo studies, which could assist in the identification of novel roles for IP5 2-K in mammals. PMID:22745128

  6. Characterization of glycosyl inositol phosphoryl ceramides from plants and fungi by mass spectrometry.

    PubMed

    Buré, Corinne; Cacas, Jean-Luc; Mongrand, Sébastien; Schmitter, Jean-Marie

    2014-02-01

    Although glycosyl inositol phosphoryl ceramides (GIPCs) represent the most abundant class of sphingolipids in plants, they still remain poorly characterized in terms of structure and biodiversity. More than 50 years after their discovery, little is known about their subcellular distribution and their exact roles in membrane structure and biological functions. This review is focused on extraction and characterization methods of GIPCs occurring in plants and fungi. Global methods for characterizing ceramide moieties of GIPCs revealed the structures of long-chain bases (LCBs) and fatty acids (FAs): LCBs are dominated by tri-hydroxylated molecules such as monounsaturated and saturated phytosphingosine (t18:1 and t18:0, respectively) in plants and mainly phytosphingosine (t18:0 and t20:0) in fungi; FA are generally 14-26 carbon atoms long in plants and 16-26 carbon atoms long in fungi, these chains being often hydroxylated in position 2. Mass spectrometry plays a pivotal role in the assessment of GIPC diversity and the characterization of their structures. Indeed, it allowed to determine that the core structure of GIPC polar heads in plants is Hex(R1)-HexA-IPC, with R1 being a hydroxyl, an amine, or a N-acetylamine group, whereas the core structure in fungi is Man-IPC. Notably, information gained from tandem mass spectrometry spectra was most useful to describe the huge variety of structures encountered in plants and fungi and reveal GIPCs with yet uncharacterized polar head structures, such as hexose-inositol phosphoceramide in Chondracanthus acicularis and (hexuronic acid)4-inositol phosphoceramide and hexose-(hexuronic acid)3-inositol phosphoceramide in Ulva lactuca. PMID:23887274

  7. A Combined Therapy with Myo-Inositol and D-Chiro-Inositol Improves Endocrine Parameters and Insulin Resistance in PCOS Young Overweight Women.

    PubMed

    Benelli, Elena; Del Ghianda, Scilla; Di Cosmo, Caterina; Tonacchera, Massimo

    2016-01-01

    Introduction. We evaluated the effects of a therapy that combines myo-inositol (MI) and D-chiro-inositol (DCI) in young overweight women affected by polycystic ovary syndrome (PCOS), characterized by oligo- or anovulation and hyperandrogenism, correlated to insulin resistance. Methods. We enrolled 46 patients affected by PCOS and, randomly, we assigned them to two groups, A and B, treated, respectively, with the association of MI plus DCI, in a 40 : 1 ratio, or with placebo (folic acid) for six months. Thus, we analyzed pretreatment and posttreatment FSH, LH, 17-beta-Estradiol, Sex Hormone Binding Globulin, androstenedione, free testosterone, dehydroepiandrosterone sulphate, HOMA index, and fasting glucose and insulin. Results. We recorded a statistically significant reduction of LH, free testosterone, fasting insulin, and HOMA index only in the group treated with the combined therapy of MI plus DCI; in the same patients, we observed a statistically significant increase of 17-beta-Estradiol levels. Conclusions. The combined therapy of MI plus DCI is effective in improving endocrine and metabolic parameters in young obese PCOS affected women. PMID:27493664

  8. A Combined Therapy with Myo-Inositol and D-Chiro-Inositol Improves Endocrine Parameters and Insulin Resistance in PCOS Young Overweight Women

    PubMed Central

    Benelli, Elena; Del Ghianda, Scilla

    2016-01-01

    Introduction. We evaluated the effects of a therapy that combines myo-inositol (MI) and D-chiro-inositol (DCI) in young overweight women affected by polycystic ovary syndrome (PCOS), characterized by oligo- or anovulation and hyperandrogenism, correlated to insulin resistance. Methods. We enrolled 46 patients affected by PCOS and, randomly, we assigned them to two groups, A and B, treated, respectively, with the association of MI plus DCI, in a 40 : 1 ratio, or with placebo (folic acid) for six months. Thus, we analyzed pretreatment and posttreatment FSH, LH, 17-beta-Estradiol, Sex Hormone Binding Globulin, androstenedione, free testosterone, dehydroepiandrosterone sulphate, HOMA index, and fasting glucose and insulin. Results. We recorded a statistically significant reduction of LH, free testosterone, fasting insulin, and HOMA index only in the group treated with the combined therapy of MI plus DCI; in the same patients, we observed a statistically significant increase of 17-beta-Estradiol levels. Conclusions. The combined therapy of MI plus DCI is effective in improving endocrine and metabolic parameters in young obese PCOS affected women. PMID:27493664

  9. Relationship Between Myo-Inositol Supplementary and Gestational Diabetes Mellitus: A Meta-Analysis.

    PubMed

    Zheng, Xiangqin; Liu, Zhaozhen; Zhang, Yulong; Lin, Yuan; Song, Jianrong; Zheng, Lianghui; Lin, Sheng

    2015-10-01

    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

  10. Amino acid depletion activates TonEBP and sodium-coupled inositol transport.

    PubMed

    Franchi-Gazzola, R; Visigalli, R; Dall'Asta, V; Sala, R; Woo, S K; Kwon, H M; Gazzola, G C; Bussolati, O

    2001-06-01

    The expression of the osmosensitive sodium/myo-inositol cotransporter (SMIT) is regulated by multiple tonicity-responsive enhancers (TonEs) in the 5'-flanking region of the gene. In response to hypertonicity, the nuclear abundance of the transcription factor TonE-binding protein (TonEBP) is increased, and the transcription of the SMIT gene is induced. Transport system A for neutral amino acids, another osmosensitive mechanism, is progressively stimulated if amino acid substrates are not present in the extracellular compartment. Under this condition, as in hypertonicity, cells shrink and mitogen-activated protein kinases are activated. We demonstrate here that a clear-cut nuclear redistribution of TonEBP, followed by SMIT expression increase and inositol transport activation, is observed after incubation of cultured human fibroblasts in Earle's balanced salts (EBSS), an isotonic, amino acid-free saline. EBSS-induced SMIT stimulation is prevented by substrates of system A, although these compounds do not compete with inositol for transport through SMIT. We conclude that the incubation in isotonic, amino acid-free saline triggers an osmotic stimulus and elicits TonEBP-dependent responses like hypertonic treatment. PMID:11350742

  11. Activation of Ca2+ entry into acinar cells by a non-phosphorylatable inositol trisphosphate

    NASA Astrophysics Data System (ADS)

    Bird, G. S. J.; Rossier, M. F.; Hughes, A. R.; Shears, S. B.; Armstrong, D. L.; , J. W. Putney, Jr.

    1991-07-01

    IN many cell types, receptor activation of phosphoinositidase C results in an initial release of intracellular Ca2+ stores followed by sustained Ca2+ entry across the plasma membrane. Inositol 1,4,5-trisphosphate is the mediator of the initial Ca2+ release1, although its role in the mechanism underlying Ca2+ entry remains controversial1-6. We have now used two techniques to introduce inositol phosphates into mouse lacrimal acinar cells and measure their effects on Ca2+ entry: microinjection into cells loaded with Fura-2, a fluorescent dye which allows the measurement of intra-cellular free calcium concentration by microspectrofluorimetry, and perfusion of patch clamp pipettes in the whole-cell configuration while monitoring the activity of Ca2+-activated K+ channels as an indicator of intracellular Ca2+. We report here that inositol 1,4,5-trisphosphate serves as a signal that is both necessary and sufficient for receptor activation of Ca2+ entry across the plasma membrane in these cells.

  12. Phospholipids of subcellular organelles isolated from cultured BHK cells.

    PubMed

    Brotherus, J; Renkonen, O

    1977-02-23

    Mitochondrial and nuclei were purified from cultured hamster fibroblasts (BHK21 cells) by centrifugation in sucrose gradients. The phospholipid compositions of the preparations were compared to those of the previously purified plasma membranes, endoplasmic reticulum and lysosomes. The mitochondria had a characteristically high content (approx. 16% of lipid phosphorus) of cardiolipin, which was practically absent from the other purified organelles. The nuclei were enriched in phosphatidylcholine and phosphatidylinositol (approx. 68% and 5% of lipid phosphorus, respectively). Lysobisphosphatidic acid was almost absent from the mitochondria and nuclei, as well as from the plasma membrane and endoplasmic reticulum, which suggests that this phospholipid is confined to the lysosomes of the BHK cell. The nuclei and the mitochondria contained relatively little sphingomyelin, a characteristic lipid of the plasma membrane. The distributions of the total cellular phospholipid and protein between the various organelles were calculated and compared to the corresponding data estimated for the rat liver. The BHK cell contained relatively more phospholipids in the nucleus and the lysosomes than the liver. All the organelles of the BHK cell contained less protein per phospholipid than the equivalent organelles of the liver. PMID:836856

  13. Ibuprofen-phospholipid solid dispersions: improved dissolution and gastric tolerance.

    PubMed

    Hussain, M Delwar; Saxena, Vipin; Brausch, James F; Talukder, Rahmat M

    2012-01-17

    Solid dispersions of ibuprofen with various phospholipids were prepared, and the effect of phospholipids on the in vitro dissolution and in vivo gastrointestinal toxicity of ibuprofen was evaluated. Most phospholipids improved the dissolution of ibuprofen; dimyristoylphosphatidyl-glycerol (DMPG) had the greatest effect. At 45 min, the extent of dissolution of ibuprofen from the ibuprofen-DMPG system (weight ratio 9:1) increased about 69% compared to ibuprofen alone; the initial rate of dissolution increased sevenfold. Increasing the DMPG content from 9:1 to 4:1 in this system did not significantly increase the rate and the extent of dissolution. X-ray diffraction and scanning electron micrograph indicated a smaller crystallite size of ibuprofen with fairly uniform distribution in the ibuprofen-DMPG solid dispersion. A small amount of carrier phospholipid significantly increases the rate and the extent of dissolution, which may increase the bioavailability of ibuprofen. The number of ulcers >0.5mm in size formed in the gastric mucosa of rats following ibuprofen, DMPG, DMPC and DPPC solid dispersions (ibuprofen and phospholipid weight ratio 4:1) were 8.6 ± 6.2, 3.9 ± 5.3, 5.3 ± 4.9 and 9.1 ± 7.4, respectively. Solid dispersion of ibuprofen with DMPG was significantly less irritating to the gastric mucosa than ibuprofen itself (one-way ANOVA, p<0.05). Solid dispersion of ibuprofen and DMPG decreases the gastric side effects of ibuprofen. PMID:22101290

  14. Tracing Viable Bacteria in Wadden Sea Sediments Using Phospholipid Analysis

    NASA Astrophysics Data System (ADS)

    Ruetters, H.; Sass, H.; Cypionka, H.; Rullkotter, J.

    2001-12-01

    Lipid analysis is a commonly used tool for chemotaxonomical characterization of bacterial strains. In particular, phospholipids - determined as polar lipid fatty acids (PLFA) - have proven to be appropriate biomarkers for viable bacterial cells. In this study the lipid content of different bacterial isolates from an intertidal mudflat (Wadden Sea, NW Germany) was investigated. To identify the phospholipids present in the isolated bacteria, fractionated lipid extracts were studied using HPLC-ESI-MS and -MS-MS. This technique gives information on types of phospholipids and their corresponding fatty acid substituents. It could be shown by cluster analyses that the combined information of phospholipid types and corresponding fatty acids allows a better differentiation of bacterial groups than fatty acid patterns determined after whole cell hydrolysis. Sedimentary microbial communities were studied by an interdisciplinary approach using microbiological as well as geochemical techniques. Characteristic phospholipids were traced in the sediment cores (0-70 cm) in order to estimate the relative contributions of different bacterial groups to the sedimentary microbial communities. Seasonal variations of environmental parameters (temperature, sulfate concentrations, oxygen availability etc.) and their influence on the microbial communities were studied.

  15. Morphological and Physical Analysis of Natural Phospholipids-Based Biomembranes

    PubMed Central

    Jacquot, Adrien; Francius, Grégory; Razafitianamaharavo, Angelina; Dehghani, Fariba; Tamayol, Ali; Linder, Michel; Arab-Tehrany, Elmira

    2014-01-01

    Background Liposomes are currently an important part of biological, pharmaceutical, medical and nutritional research, as they are considered to be among the most effective carriers for the introduction of various types of bioactive agents into target cells. Scope of Review In this work, we study the lipid organization and mechanical properties of biomembranes made of marine and plant phospholipids. Membranes based on phospholipids extracted from rapeseed and salmon are studied in the form of liposome and as supported lipid bilayer. Dioleylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) are used as references to determine the lipid organization of marine and plant phospholipid based membranes. Atomic force microscopy (AFM) imaging and force spectroscopy measurements are performed to investigate the membranes' topography at the micrometer scale and to determine their mechanical properties. Major Conclusions The mechanical properties of the membranes are correlated to the fatty acid composition, the morphology, the electrophoretic mobility and the membrane fluidity. Thus, soft and homogeneous mechanical properties are evidenced for salmon phospholipids membrane containing various polyunsaturated fatty acids. Besides, phase segregation in rapeseed membrane and more important mechanical properties were emphasized for this type of membranes by contrast to the marine phospholipids based membranes. General Significance This paper provides new information on the nanomechanical and morphological properties of membrane in form of liposome by AFM. The originality of this work is to characterize the physico-chemical properties of the nanoliposome from the natural sources containing various fatty acids and polar head. PMID:25238543

  16. Identification of a Plasmodium falciparum Phospholipid Transfer Protein*

    PubMed Central

    van Ooij, Christiaan; Withers-Martinez, Chrislaine; Ringel, Alessa; Cockcroft, Shamshad; Haldar, Kasturi; Blackman, Michael J.

    2013-01-01

    Infection of erythrocytes by the human malaria parasite Plasmodium falciparum results in dramatic modifications to the host cell, including changes to its antigenic and transport properties and the de novo formation of membranous compartments within the erythrocyte cytosol. These parasite-induced structures are implicated in the transport of nutrients, metabolic products, and parasite proteins, as well as in parasite virulence. However, very few of the parasite effector proteins that underlie remodeling of the host erythrocyte are functionally characterized. Using bioinformatic examination and modeling, we have found that the exported P. falciparum protein PFA0210c belongs to the START domain family, members of which mediate transfer of phospholipids, ceramide, or fatty acids between membranes. In vitro phospholipid transfer assays using recombinant PFA0210 confirmed that it can transfer phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, and sphingomyelin between phospholipid vesicles. Furthermore, assays using HL60 cells containing radiolabeled phospholipids indicated that orthologs of PFA0210c can also transfer phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. Biochemical and immunochemical analysis showed that PFA0210c associates with membranes in infected erythrocytes at mature stages of intracellular parasite growth. Localization studies in live parasites revealed that the protein is present in the parasitophorous vacuole during growth and is later recruited to organelles in the parasite. Together these data suggest that PFA0210c plays a role in the formation of the membranous structures and nutrient phospholipid transfer in the malaria-parasitized erythrocyte. PMID:24043620

  17. Expression, Purification, Crystallisation and X-ray Crystallographic Analysis of a Truncated Form of Human Src Homology 2 Containing Inositol 5-Phosphatase 2.

    PubMed

    Le Coq, Johanne; Heredia Gallego, Luis; Lietha, Daniel

    2016-06-01

    The Src homology 2 containing inositol 5-phosphatase 2 (SHIP2) catalyses the dephosphorylation of the phospholipid phosphatidylinositol 3,4,5-triphosphate (PI(3,4,5)P3) to form PI(3,4)P2. PI(3,4,5)P3 is a key lipid second messenger, which can recruit signalling proteins to the plasma membrane and subsequently initiate numerous downstream signalling pathways responsible for the regulation of a plethora of cellular events such as proliferation, growth, apoptosis and cytoskeletal rearrangements. SHIP2 has been heavily implicated with several serious diseases such as cancer and type 2 diabetes but its regulation remains poorly understood. In order to gain insight into the mechanisms of SHIP2 regulation, a fragment of human SHIP2 containing the phosphatase domain and a region proposed to resemble a C2 domain was crystallized. Currently, no structural information is available on the putative C2-related domain or its relative position with respect to the phosphatase domain. Initial crystals were polycrystalline, but were optimized to obtain diffraction data to a resolution of 2.1 Å. Diffraction data analysis revealed a P212121 space group with unit cell parameters a = 136.04 Å, b = 175.84 Å, c = 176.89 Å. The Matthews coefficient is 2.54 Å(3) Da(-1) corresponding to 8 molecules in the asymmetric unit with a solvent content of 51.7 %. PMID:27170292

  18. Effect of a myo-Inositol Antagonist, 2-O, C-Methylene-myo-Inositol, on the Metabolism of myo-Inositol-2-3H and d-Glucose-1-14C in Lilium longiflorum Pollen 1

    PubMed Central

    Chen, Minshen; Loewus, Mary Walz; Loewus, Frank A.

    1977-01-01

    2-O,C-Methylene-myo-inositol (MMO), a myo-inositol (MI) antagonist, inhibits germination and tube elongation of pollen from Lilium longiflorum cv. Ace or 44. The presence of 5 mm MMO in Dickinson's pentaerythritol medium (Plant Physiol. 43:1-8) partially blocks germination. The tubes produced are short and fail to elongate. In the presence of MI, MMO's toxic effect is blocked. As little as 0.56 mm MI will maintain normal germination in the presence of 43 mm MMO, and pollen tubes continue to elongate for 2 to 3 hr. Eventually, the toxic action of MMO prevents further growth. MMO does not inhibit UDP-d-glucose dehydrogenase from lily pollen. Uptake of MI-2-3H and incorporation of tritium into galacturonic acid and pentose units of tube wall pectin are blocked by MMO. The site of this inhibition is undertermined. Uptake of d-glucose-1-14C and incorporation of 14C into 70% ethyl alcohol-insoluble polysaccharides of germinated pollen are not blocked by MMO, but distribution of label into polysaccharide product is altered. In MMO-treated pollen, very little 14C is found in uronic acid or pentose units. At 30 mm MMO, about two-thirds of the carbon flow from d-glucose to these pectic components is interrupted. MMO also alters d-glucose metabolism in the 70% ethyl alcohol-soluble fraction, but the compound involved must still be identified. These results offer fresh evidence of an intermediary role for MI during UDP-d-glucuronate biosynthesis in germinated pollen. PMID:16659913

  19. 4.1N binding regions of inositol 1,4,5-trisphosphate receptor type 1.

    PubMed

    Fukatsu, Kazumi; Bannai, Hiroko; Inoue, Takafumi; Mikoshiba, Katsuhiko

    2006-04-01

    Zhang et al. and Maximov et al. [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 278 (2003) 4048-4056; A. Maximov, T. S. Tang, and I. Bezprozvanny, Association of the type 1 inositol (1,4,5)-trisphosphate receptor with 4.1N protein in neurons, Mol. Cell. Neurosci. 22 (2003) 271-283.] reported that 4.1N is a binding partner of inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1), however the binding site of IP(3)R1 differed: the former determined the C-terminal 14 amino acids of the cytoplasmic tail (CTT14aa) as the binding site, while the latter assigned another segment, cytoplasmic tail middle 1 (CTM1). To solve this discrepancy, we performed immunoprecipitation and found that both the segments had binding activity to 4.1N. Both segments also interfered the 4.1N-regulated IP(3)R1 diffusion in neuronal dendrites. However, IP(3)R1 lacking the CTT14aa (IP(3)R1-DeltaCTT14aa) does not bind to 4.1N [S. Zhang, A. Mizutani, C. Hisatsune, T. Higo, H. Bannai, T. Nakayama, M. Hattori, and K. Mikoshiba, Protein 4.1N is required for translocation of inositol 1,4,5-trisphosphate receptor type 1 to the basolateral membrane domain in polarized Madin-Darby canine kidney cells, J. Biol. Chem. 278 (2003) 4048-4056.] and its diffusion constant is larger than that of IP(3)R1 full-length in neuronal dendrites [K. Fukatsu, H. Bannai, S. Zhang, H. Nakamura, T. Inoue, and K. Mikoshiba, Lateral diffusion of inositol 1,4,5-trisphosphate receptor type 1 is regulated by actin filaments and 4.1N in neuronal dendrites, J. Biol. Chem. 279 (2004) 48976-48982.]. We conclude that both the CTT14aa and CTM1 sequences can bind to 4.1N in peptide fragment forms. However, we propose that the responsible binding site for 4.1N binding in full-length tetramer form of IP

  20. Plasma phospholipid mass transfer rate: relationship to plasma phospholipid and cholesteryl ester transfer activities and lipid parameters.

    PubMed

    Cheung, M C; Wolfbauer, G; Albers, J J

    1996-09-27

    Human plasma phospholipid transfer protein (PLTP) has been shown to facilitate the transfer of phospholipid from liposomes or isolated very low and low density lipoproteins to high density lipoproteins. Its activity in plasma and its physiological function are presently unknown. To elucidate the role of PLTP in lipoprotein metabolism and to delineate factors that may affect the rate of phospholipid transfer between lipoproteins, we determined the plasma phospholipid mass transfer rate (PLTR) in 16 healthy adult volunteers and assessed its relationship to plasma lipid levels, and to phospholipid transfer activity (PLTA) and cholesteryl ester transfer activity (CETA) measured by radioassays. The plasma PLTR in these subjects was 27.2 +/- 11.8 nmol/ml per h at 37 degrees C (mean +/- S.D.), and their PLTA and CETA were 13.0 +/- 1.7 mumol/ml per h and 72.8 +/- 15.7 nmol/ml per h, respectively. Plasma PLTR was correlated directly with total, non-HDL, and HDL triglyceride (rs = 0.76, P < 0.001), total and non-HDL phospholipid (rs > 0.53, P < 0.05), and inversely with HDL free cholesterol (rs = -0.54, P < 0.05), but not with plasma PLTA and CETA. When 85% to 96% of the PLTA in plasma was removed by polyclonal antibodies against recombinant human PLTP, phospholipid mass transfer from VLDL and LDL to HDL was reduced by 50% to 72%, but 80% to 100% of CETA could still be detected. These studies demonstrate that PLTP plays a major role in facilitating the transfer of phospholipid between lipoproteins, and suggest that triglyceride is a significant modulator of intravascular phospholipid transport. Furthermore, most of the PLTP and CETP in human plasma is associated with different particles. Plasma PLTA and CETA were also measured in mouse, rat, hamster, guinea pig, rabbit, dog, pig, and monkey. Compared to human, PLTA in rat and mouse was significantly higher and in rabbit and guinea pig was significantly lower while the remaining animal species had PLTA similar to humans. No

  1. Neutron diffraction studies of amphipathic helices in phospholipid bilayers

    SciTech Connect

    Bradshaw, J.P.; Gilchrist, P.J.; Duff, K.C.; Saxena, A.M.

    1994-12-31

    The structural feature which is thought to facilitate the interaction of many peptides with phospholipid bilayers is the ability to fold into an amphipathic helix. In most cases the exact location and orientation of this helix with respect to the membrane is not known, and may vary with factors such as pH and phospholipid content of the bilayer. The growing interest in this area is stimulated by indications that similar interactions can contribute to the binding of certain hormones to their cell-surface receptors. We have been using the techniques of neutron diffraction from stacked phospholipid bilayers in an attempt to investigate this phenomenon with a number of membrane-active peptides. Here we report some of our findings with three of these: the bee venom melittin; the hormone calcitonin; and a synthetic peptide representing the ion channel fragment of influenza A M2 protein.

  2. The role of lamellate phospholipid bilayers in lubrication of joints.

    PubMed

    Pawlak, Zenon; Urbaniak, Wiesław; Gadomski, Adam; Yusuf, Kehinde Q; Afara, Isaac O; Oloyede, Adekunle

    2012-01-01

    This study aims to determine the effect of progressive loss of the surface active phospholipids on the characteristics, and hence tribological function of articular cartilage. In accordance to Hill's hypothesis, 3-7 lipid bilayers at pH 7.4 operate as the solid lubricant in the cartilage-cartilage interface during physiological function. These bilayers are known to be depleted during cartilage degeneration. This study models this loss of phospholipid bilayers, studying experimentally both wet and dry cartilage surfaces, measuring surface wettability, and friction coefficient under a constant stress of 1.2 MPa. The results demonstrate that the friction coefficient increases gradually with loss of the phospholipid bilayers, and gains in value with decrease in wettability. PMID:23394101

  3. Intestinal interaction of bile acids, phospholipids, dietary fibers, and cholestyramine.

    PubMed

    Gallaher, D; Schneeman, B O

    1986-04-01

    Binding of bile acids and phospholipids to a number of dietary fibers and cholestyramine (CH) within the small intestine was determined. The fibers used were cellulose, wheat bran, oat bran, guar gum (GG), and lignin (LG). GG, LG, and CH bound significant quantities of bile acids. However, only the CH reduced the bile acid concentration within the aqueous phase of the intestinal contents. Significant phospholipid binding was found only with CH. None of the test substances significantly reduced the quantity of solubilized lipid. Multiple regression analysis indicated that the total quantity of bile acids and phospholipids in the aqueous phase of the intestinal contents was a significant predictor of the quantity of lipid solubilized within the contents (r2 = 0.67). The failure of GG and LG to significantly decrease the amount of solubilized lipid suggests that the hypocholesterolemic effect of these fibers is due more to their bile acid binding capacity than to an effect on lipid solubilization. PMID:3008573

  4. Shear-induced morphology in mixed phospholipid films

    NASA Astrophysics Data System (ADS)

    Hirsa, Amir; Young, James; Posada, David; Lopez, Juan

    2014-11-01

    Flow of mixed phospholipid films on liquid surfaces plays a significant role in biological processes ranging from lipid bilayer fluidity and the associated behavior of cellular membranes, to flow on the liquid lining in the lungs. Phospholipid films are also central to the process of two-dimensional protein crystallization below a ligand-bearing film. Here, we study a binary mixture of phospholipids that form an insoluble monolayer on the air-water interface. Brewster angle microscopy reveals that a shearing flow induces a phase separation in the binary film, resulting in the appearance of 10 micron-scale dark domains. Hydrodynamic response of the binary film is quantified at the macro-scale by measurements of the surface shear viscosity, via a deep-channel surface viscometer. Reynolds number was shown to be a state variable, along with surface pressure, controlling the surface shear viscosity of a biotinylated lipid film.

  5. Possible mechanism of adhesion in a mica supported phospholipid bilayer

    SciTech Connect

    Pertsin, Alexander; Grunze, Michael

    2014-05-14

    Phospholipid bilayers supported on hydrophilic solids like silica and mica play a substantial role in fundamental studies and technological applications of phospholipid membranes. In both cases the molecular mechanism of adhesion between the bilayer and the support is of primary interest. Since the possibilities of experimental methods in this specific area are rather limited, the methods of computer simulation acquire great importance. In this paper we use the grand canonical Monte Carlo technique and an atomistic force field to simulate the behavior of a mica supported phospholipid bilayer in pure water as a function of the distance between the bilayer and the support. The simulation reveals a possible adhesion mechanism, where the adhesion is due to individual lipid molecules that protrude from the bilayer and form widely spaced links with the support. Simultaneously, the bilayer remains separated from the bilayer by a thin water interlayer which maintains the bilayer fluidity.

  6. Phospholipid flippases: building asymmetric membranes and transport vesicles

    PubMed Central

    Sebastian, Tessy T.; Baldridge, Ryan D.; Xu, Peng; Graham, Todd R.

    2012-01-01

    Phospholipid flippases in the type IV P-type ATPase family (P4-ATPases) are essential components of the Golgi, plasma membrane and endosomal system that play critical roles in membrane biogenesis. These pumps flip phospholipid across the bilayer to create an asymmetric membrane structure with substrate phospholipids, such as phosphatidylserine and phosphatidylethanolamine, enriched within the cytosolic leaflet. The P4-ATPases also help form transport vesicles that bud from Golgi and endosomal membranes, thereby impacting the sorting and localization of many different proteins in the secretory and endocytic pathways. At the organismal level, P4-ATPase deficiencies are linked to liver disease, obesity, diabetes, hearing loss, neurological deficits, immune deficiency and reduced fertility. Here, we review the biochemical, cellular and physiological functions of P4-ATPases, with an emphasis on their roles in vesicle-mediated protein transport. PMID:22234261

  7. The mechanism of acyl specific phospholipid remodeling by tafazzin

    PubMed Central

    Schlame, Michael; Acehan, Devrim; Berno, Bob; Xu, Yang; Valvo, Salvatore; Ren, Mindong; Stokes, David L.; Epand, Richard M.

    2013-01-01

    Cardiolipin is a mitochondrial phospholipid with a characteristic acyl chain composition that depends on the function of tafazzin, a phospholipid-lysophospholipid transacylase, although the enzyme itself lacks acyl specificity. We incubated isolated tafazzin with various mixtures of phospholipids and lysophospholipids, characterized the lipid phase by 31P-NMR, and measured newly formed molecular species by mass spectrometry. Significant transacylation was observed only in non-bilayer lipid aggregates and the substrate specificity was highly sensitive to the lipid phase. In particular, tetralinoleoyl-cardiolipin, a prototype molecular species, formed only under conditions that favor the inverted hexagonal phase. In isolated mitochondria, <1 percent of lipids participated in transacylations, suggesting that the action of tafazzin is limited to privileged lipid domains. We propose that tafazzin reacts with non-bilayer type lipid domains that occur in curved or hemifused membrane zones, and that acyl specificity is driven by the packing properties of these domains. PMID:22941046

  8. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates

    NASA Technical Reports Server (NTRS)

    Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1993-01-01

    The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

  9. Genetic Analysis of Digestive Physiology Using Fluorescent Phospholipid Reporters

    NASA Astrophysics Data System (ADS)

    Farber, Steven A.; Pack, Michael; Ho, Shiu-Ying; Johnson, Iain D.; Wagner, Daniel S.; Dosch, Roland; Mullins, Mary C.; Hendrickson, H. Stewart; Hendrickson, Elizabeth K.; Halpern, Marnie E.

    2001-05-01

    Zebrafish are a valuable model for mammalian lipid metabolism; larvae process lipids similarly through the intestine and hepatobiliary system and respond to drugs that block cholesterol synthesis in humans. After ingestion of fluorescently quenched phospholipids, endogenous lipase activity and rapid transport of cleavage products results in intense gall bladder fluorescence. Genetic screening identifies zebrafish mutants, such as fat free, that show normal digestive organ morphology but severely reduced phospholipid and cholesterol processing. Thus, fluorescent lipids provide a sensitive readout of lipid metabolism and are a powerful tool for identifying genes that mediate vertebrate digestive physiology.

  10. Saturated anionic phospholipids enhance transdermal transport by electroporation.

    PubMed Central

    Sen, Arindam; Zhao, Ya-Li; Hui, Sek Wen

    2002-01-01

    Anionic phospholipids, but not cationic or neutral phospholipids, were found to enhance the transdermal transport of molecules by electroporation. When added as liposomes to the milieus of water-soluble molecules to be delivered through the epidermis of porcine skin by electroporation, these phospholipids enhance, by one to two orders of magnitude, the transdermal flux. Encapsulation of molecules in liposomes is not necessary. Dimyristoylphosphatidylserine (DMPS), phosphatidylserine from bovine brain (brain-PS), dioleoylphosphatidylserine (DOPS), and dioleoylphosphatidylglycerol (DOPG) were used to test factors affecting the potency of anionic lipid transport enhancers. DMPS with saturated acyl chains was found to be a much more potent transport enhancer than those with unsaturated acyl chains (DOPS and DOPG). There was no headgroup preference. Saturated DMPS was also more effective in delaying resistance recovery after pulsing, and with a greater affinity in the epidermis after pulsing. Using fluorescent carboxyl fluorescein and fluorescein isothiocyanate (FITC)-labeled Dextrans as test water-soluble molecules for transport, and rhodamine-labeled phospholipids to track anionic phospholipids, we found, by conventional and confocal fluorescence microscopy, that transport of water-soluble molecules was localized in local transport spots or regions (LTRs) created by the electroporation pulses. Anionic phospholipids, especially DMPS, were located at the center of the LTRs and spanned the entire thickness of the stratum corneum (SC). The degree of saturation of anionic phospholipids made no difference in the densities of LTRs created. We deduce that, after being driven into the epidermis by negative electric pulses, saturated anionic phospholipids mix and are retained better by the SC lipids. Anionic lipids prefer loose layers or vesicular rather than multilamellar forms, thereby prolonging the structural recovery of SC lipids to the native multilamellar form. In the

  11. Light and phospholipid driven structural transitions in nematic microdroplets

    NASA Astrophysics Data System (ADS)

    Dubtsov, A. V.; Pasechnik, S. V.; Shmeliova, D. V.; Kralj, Samo

    2014-10-01

    We studied the UV-irradiation and phospholipid driven bipolar-radial structural transitions within azoxybenzene nematic liquid crystal (LC) droplets dispersed in water. It was found that the UV-irradiation induced trans-cis isomerisation of LC molecules could enable structural transitions into radial-type configurations at a critical UV-irradiation time tc. In particular, we show that under appropriate conditions, a value of tc could sensitively fingerprint the concentration of phospholipid molecules present in LC-water dispersions. This demonstrated proof-of-principle mechanism could be exploited for development of sensitive detectors for specific nanoparticles (NPs), where value of tc reveals concentration of NPs.

  12. APOE polymorphisms influence longitudinal lipid trends preceding intracerebral hemorrhage

    PubMed Central

    Phuah, Chia-Ling; Raffeld, Miriam R.; Ayres, Alison M.; Gurol, M. Edip; Viswanathan, Anand; Greenberg, Steven M.; Biffi, Alessandro; Rosand, Jonathan

    2016-01-01

    Objective: We sought to determine whether APOE genotype influences a previously observed decline in serum total cholesterol (TC) and low-density lipoprotein (LDL) levels preceding primary intracerebral hemorrhage (ICH), as a potential demonstration of nonamyloid mechanisms of APOE in ICH risk. Methods: We performed a single-center retrospective longitudinal analysis using patients with known APOE genotype drawn from an ongoing cohort study of ICH. Serum lipid measurements for TC, triglycerides (TGs), LDL, and high-density lipoprotein (HDL) collected within 2 years before and after index ICH were extracted from electronic medical records. Piecewise linear mixed-effects models were used to compare APOE allele–specific effects on temporal serum lipid trends in ICH. Demographics, medical history, medications, and health maintenance data were included as fixed effects. Inter- and intraindividual variations in lipid levels were modeled as random effects. Results: A total of 124 ICH cases were analyzed. APOE ε4 carriers had greater rates of decline in serum TC and LDL within 6 months preceding ICH (TC: −7.30 mg/dL/mo, p = 0.0035; LDL: −8.44 mg/dL/mo, p = 0.0001). Conversely, serum TC and LDL levels in APOE ε2 carriers were unchanged within the same time period. APOE genotype had no associations with serum HDL or TG trends. Conclusions: APOE allele status predicts serum TC and LDL changes preceding acute ICH. Our results have implications for ongoing efforts in dissecting the role of dyslipidemia in cerebrovascular disease risk. APOE genotype–specific influence on lipid trends provides a clue for one mechanism by which APOE may influence risk of ICH. Further characterization of the metabolic roles of APOE is needed to improve the understanding of APOE biology in cerebrovascular disease risk. PMID:27433544

  13. Specific isoforms of protein kinase C are essential for prevention of folate-resistant neural tube defects by inositol.

    PubMed

    Cogram, Patricia; Hynes, Andrew; Dunlevy, Louisa P E; Greene, Nicholas D E; Copp, Andrew J

    2004-01-01

    A proportion of neural tube defects (NTDs) can be prevented by maternal folic acid supplementation, although some cases are unresponsive. The curly tail mutant mouse provides a model of folate-resistant NTDs, in which defects can be prevented by inositol therapy in early pregnancy. Hence, inositol represents a possible novel adjunct therapy to prevent human NTDs. The present study investigated the molecular mechanism by which inositol prevents mouse NTDs. Activation of protein kinase C (PKC) is known to be essential, and we examined neurulation-stage embryos for PKC expression and applied PKC inhibitors to curly tail embryos developing in culture. Although all known PKC isoforms were detected in the closing neural tube, use of chemical PKC inhibitors identified a particular requirement for 'conventional' PKC isoforms. Peptide inhibitors offer selective inhibition of individual PKCs, and we demonstrated isoform-specific inhibition of PKC in embryonic cell cultures. Application of peptide inhibitors to neurulation-stage embryos revealed an absolute dependence on the activity of PKCbetaI and gamma for prevention of NTDs by inositol, and partial dependence on PKCzeta, whereas other PKCs (alpha, betaII delta, and epsilon) were dispensable. To investigate the cellular action of inositol and PKCs in NTD prevention, we examined cell proliferation in curly tail embryos. Defective proliferation of hindgut cells is a key component of the pathogenic sequence leading to NTDs in curly tail. Hindgut cell proliferation was stimulated specifically by inositol, an effect that required activation of PKCbetaI. Our findings reveal an essential role of specific PKC isoforms in mediating the prevention of mouse NTDs by inositol. PMID:14613966

  14. Variations in myo-inositol in fronto-limbic regions and clinical response to electroconvulsive therapy in major depression.

    PubMed

    Njau, Stephanie; Joshi, Shantanu H; Leaver, Amber M; Vasavada, Megha; Van Fleet, Jessica; Espinoza, Randall; Narr, Katherine L

    2016-09-01

    Though electroconvulsive therapy (ECT) is an established treatment for severe depression, the neurobiological factors accounting for the clinical effects of ECT are largely unknown. Myo-inositol, a neurometabolite linked with glial activity, is reported as reduced in fronto-limbic regions in patients with depression. Whether changes in myo-inositol relate to the antidepressant effects of ECT is unknown. Using magnetic resonance spectroscopy ((1)H-MRS), we measured dorsomedial anterior cingulate cortex (dmACC) and left and right hippocampal myo-inositol in 50 ECT patients (mean age: 43.78, 14 SD) and 33 controls (mean age: 39.33, 12 SD) to determine cross sectional effects of diagnosis and longitudinal effects of ECT. Patients were scanned prior to treatment, after the second ECT and at completion of the ECT index series. Controls were scanned twice at intervals corresponding to patients' baseline and end of treatment scans. Myo-inositol increased over the course of ECT in the dmACC (p = 0.042). A significant hemisphere by clinical response effect was observed for the hippocampus (p = 0.003) where decreased myo-inositol related to symptom improvement in the left hippocampus. Cross-sectional differences between patients and controls at baseline were not detected. Changes in myo-inositol observed in the dmACC in association with ECT and in the hippocampus in association with ECT-related clinical response suggest the mechanisms of ECT could include gliogenesis or a reversal of gliosis that differentially affect dorsal and ventral limbic regions. Change in dmACC myo-inositol diverged from control values with ECT suggesting compensation, while hippocampal change suggested normalization. PMID:27285661

  15. Precedence based speech segregation in bilateral cochlear implant users.

    PubMed

    Hossain, Shaikat; Montazeri, Vahid; Assmann, Peter F; Litovsky, Ruth Y

    2015-12-01

    The precedence effect (PE) enables the perceptual dominance by a source (lead) over an echo (lag) in reverberant environments. In addition to facilitating sound localization, the PE can play an important role in spatial unmasking of speech. Listeners attending to binaural vocoder simulations with identical channel center frequencies and phase demonstrated PE-based benefits in a closed-set speech segregation task. When presented with the same stimuli, bilateral cochlear implant users did not derive such benefits. These findings suggest that envelope extraction in itself may not lead to a breakdown of the PE benefits, and that other factors may play a role. PMID:26723365

  16. Precedence based speech segregation in bilateral cochlear implant users

    PubMed Central

    Hossain, Shaikat; Montazeri, Vahid; Assmann, Peter F.; Litovsky, Ruth Y.

    2015-01-01

    The precedence effect (PE) enables the perceptual dominance by a source (lead) over an echo (lag) in reverberant environments. In addition to facilitating sound localization, the PE can play an important role in spatial unmasking of speech. Listeners attending to binaural vocoder simulations with identical channel center frequencies and phase demonstrated PE-based benefits in a closed-set speech segregation task. When presented with the same stimuli, bilateral cochlear implant users did not derive such benefits. These findings suggest that envelope extraction in itself may not lead to a breakdown of the PE benefits, and that other factors may play a role. PMID:26723365

  17. Measurement of Inositol 1,4,5-Trisphosphate in Living Cells Using an Improved Set of Resonance Energy Transfer-Based Biosensors

    PubMed Central

    Tóth, Dániel J.; Kurucz, István; Hunyady, László; Balla, Tamas; Várnai, Péter

    2015-01-01

    Improved versions of inositol-1,4,5-trisphosphate (InsP3) sensors were created to follow intracellular InsP3 changes in single living cells and in cell populations. Similar to previous InsP3 sensors the new sensors are based on the ligand binding domain of the human type-I InsP3 receptor (InsP3R-LBD), but contain a mutation of either R265K or R269K to lower their InsP3 binding affinity. Tagging the InsP3R-LBD with N-terminal Cerulean and C-terminal Venus allowed measurement of InsP3 in single-cell FRET experiments. Replacing Cerulean with a Luciferase enzyme allowed experiments in multi-cell format by measuring the change in the BRET signal upon stimulation. These sensors faithfully followed the agonist-induced increase in InsP3 concentration in HEK 293T cells expressing the Gq-coupled AT1 angiotensin receptor detecting a response to agonist concentration as low as 10 pmol/L. Compared to the wild type InsP3 sensor, the mutant sensors showed an improved off-rate, enabling a more rapid and complete return of the signal to the resting value of InsP3 after termination of M3 muscarinic receptor stimulation by atropine. For parallel measurements of intracellular InsP3 and Ca2+ levels in BRET experiments, the Cameleon D3 Ca2+ sensor was modified by replacing its CFP with luciferase. In these experiments depletion of plasma membrane PtdIns(4,5)P2 resulted in the fall of InsP3 level, followed by the decrease of the Ca2+-signal evoked by the stimulation of the AT1 receptor. In contrast, when type-III PI 4-kinases were inhibited with a high concentration of wortmannin or a more specific inhibitor, A1, the decrease of the Ca2+-signal preceded the fall of InsP3 level indicating an InsP3-, independent, direct regulation of capacitative Ca2+ influx by plasma membrane inositol lipids. Taken together, our results indicate that the improved InsP3 sensor can be used to monitor both the increase and decrease of InsP3 levels in live cells suitable for high-throughput BRET applications

  18. Expectations from preceding prosody influence segmentation in online sentence processing

    PubMed Central

    Brown, Meredith; Salverda, Anne Pier; Dilley, Laura C.; Tanenhaus, Michael K.

    2013-01-01

    Previous work examining prosodic cues in online spoken-word recognition has focused primarily on local cues to word identity. However, recent studies have suggested that utterance-level prosodic patterns can also influence the interpretation of subsequent sequences of lexically ambiguous syllables (Dilley, Mattys, & Vinke, Journal of Memory and Language, 63:274–294, 2010; Dilley & McAuley, Journal of Memory and Language, 59:294–311, 2008). To test the hypothesis that these distal prosody effects are based on expectations about the organization of upcoming material, we conducted a visual-world experiment. We examined fixations to competing alternatives such as pan and panda upon hearing the target word panda in utterances in which the acoustic properties of the preceding sentence material had been manipulated. The proportions of fixations to the monosyllabic competitor were higher beginning 200 ms after target word onset when the preceding prosody supported a prosodic constituent boundary following pan-, rather than following panda. These findings support the hypothesis that expectations based on perceived prosodic patterns in the distal context influence lexical segmentation and word recognition. PMID:21968925

  19. Continental warming preceding the Palaeocene-Eocene thermal maximum.

    PubMed

    Secord, Ross; Gingerich, Philip D; Lohmann, Kyger C; Macleod, Kenneth G

    2010-10-21

    Marine and continental records show an abrupt negative shift in carbon isotope values at ∼55.8 Myr ago. This carbon isotope excursion (CIE) is consistent with the release of a massive amount of isotopically light carbon into the atmosphere and was associated with a dramatic rise in global temperatures termed the Palaeocene-Eocene thermal maximum (PETM). Greenhouse gases released during the CIE, probably including methane, have often been considered the main cause of PETM warming. However, some evidence from the marine record suggests that warming directly preceded the CIE, raising the possibility that the CIE and PETM may have been linked to earlier warming with different origins. Yet pre-CIE warming is still uncertain. Disentangling the sequence of events before and during the CIE and PETM is important for understanding the causes of, and Earth system responses to, abrupt climate change. Here we show that continental warming of about 5 °C preceded the CIE in the Bighorn Basin, Wyoming. Our evidence, based on oxygen isotopes in mammal teeth (which reflect temperature-sensitive fractionation processes) and other proxies, reveals a marked temperature increase directly below the CIE, and again in the CIE. Pre-CIE warming is also supported by a negative amplification of δ(13)C values in soil carbonates below the CIE. Our results suggest that at least two sources of warming-the earlier of which is unlikely to have been methane-contributed to the PETM. PMID:20962843

  20. Effect of preceding speech on nonspeech sound perception

    NASA Astrophysics Data System (ADS)

    Stephens, Joseph D.; Holt, Lori L.

    2002-05-01

    Data from Japanese quail suggest that the effect of preceding liquids (/l/ or /r/) on response to subsequent stops (/g/ or /d/) arises from general auditory processes sensitive to the spectral structure of sound [A. J. Lotto, K. R. Kluender, and L. L. Holt, J. Acoust. Soc. Am. 102, 1134-1140 (1997)]. If spectral content is key, appropriate nonspeech sounds should influence perception of speech sounds and vice versa. The former effect has been demonstrated [A. J. Lotto and K. R. Kluender, Percept. Psychophys. 60, 602-619 (1998)]. The current experiment investigated the influence of speech on the perception of nonspeech sounds. Nonspeech stimuli were 80-ms chirps modeled after the F2 and F3 transitions in /ga/ and /da/. F3 onset was increased in equal steps from 1800 Hz (/ga/ analog) to 2700 Hz (/da/ analog) to create a ten-member series. During AX discrimination trials, listeners heard chirps that were three steps apart on the series. Each chirp was preceded by a synthesized /al/ or /ar/. Results showed context effects predicted from differences in spectral content between the syllables and chirps. These results are consistent with the hypothesis that spectral contrast influences context effects in speech perception. [Work supported by ONR, NOHR, and CNBC.

  1. Selective attention in the honeybee optic lobes precedes behavioral choices

    PubMed Central

    Paulk, Angelique C.; Stacey, Jacqueline A.; Pearson, Thomas W. J.; Taylor, Gavin J.; Moore, Richard J. D.; Srinivasan, Mandyam V.; van Swinderen, Bruno

    2014-01-01

    Attention allows animals to respond selectively to competing stimuli, enabling some stimuli to evoke a behavioral response while others are ignored. How the brain does this remains mysterious, although it is increasingly evident that even animals with the smallest brains display this capacity. For example, insects respond selectively to salient visual stimuli, but it is unknown where such selectivity occurs in the insect brain, or whether neural correlates of attention might predict the visual choices made by an insect. Here, we investigate neural correlates of visual attention in behaving honeybees (Apis mellifera). Using a closed-loop paradigm that allows tethered, walking bees to actively control visual objects in a virtual reality arena, we show that behavioral fixation increases neuronal responses to flickering, frequency-tagged stimuli. Attention-like effects were reduced in the optic lobes during replay of the same visual sequences, when bees were not able to control the visual displays. When bees were presented with competing frequency-tagged visual stimuli, selectivity in the medulla (an optic ganglion) preceded behavioral selection of a stimulus, suggesting that modulation of early visual processing centers precedes eventual behavioral choices made by these insects. PMID:24639490

  2. Diastolic dysfunction precedes hypoxia-induced mortality in dystrophic mice

    PubMed Central

    Townsend, DeWayne

    2015-01-01

    Duchenne muscular dystrophy (DMD) is a progressive striated muscle disease that is characterized by skeletal muscle weakness with progressive respiratory and cardiac failure. Together respiratory and cardiac disease account for the majority of mortality in the DMD patient population. However, little is known regarding the effects of respiratory dysfunction on the dystrophic heart. The studies described here examine the effects of acute hypoxia on cardiac function. These studies demonstrate, for the first time, that a mouse model of DMD displays significant mortality following acute exposure to hypoxia. This mortality is characterized by a steady decline in systolic function. Retrospective analysis reveals that significant decreases in diastolic dysfunction, especially in the right ventricle, precede the decline in systolic pressure. The initial hemodynamic response to acute hypoxia in the mouse is similar to that observed in larger species, with significant increases in right ventricular afterload and decreases in left ventricular preload being observed. Significant increases in heart rate and contractility suggest hypoxia-induced activation of the sympathetic nervous system. These studies provide evidence that while hypoxia presents significant hemodynamic challenges to the dystrophic right ventricle, global cardiac dysfunction precedes hypoxia-induced mortality in the dystrophic heart. These findings are clinically relevant as the respiratory insufficiency evident in patients with DMD results in significant bouts of hypoxia. The results of these studies indicate that hypoxia may contribute to the acceleration of the heart disease in DMD patients. Importantly, hypoxia can be avoided through the use of ventilatory support. PMID:26311833

  3. Pronounced kidney hypoxia precedes albuminuria in type 1 diabetic mice.

    PubMed

    Franzén, Stephanie; Pihl, Liselotte; Khan, Nadeem; Gustafsson, Håkan; Palm, Fredrik

    2016-05-01

    Intrarenal tissue hypoxia has been proposed as a unifying mechanism for the development of chronic kidney disease, including diabetic nephropathy. However, hypoxia has to be present before the onset of kidney disease to be the causal mechanism. To establish whether hypoxia precedes the onset of diabetic nephropathy, we implemented a minimally invasive electron paramagnetic resonance oximetry technique using implanted oxygen sensing probes for repetitive measurements of in vivo kidney tissue oxygen tensions in mice. Kidney cortex oxygen tensions were measured before and up to 15 days after the induction of insulinopenic diabetes in male mice and compared with normoglycemic controls. On day 16, urinary albumin excretions and conscious glomerular filtration rates were determined to define the temporal relationship between intrarenal hypoxia and disease development. Diabetic mice developed pronounced intrarenal hypoxia 3 days after the induction of diabetes, which persisted throughout the study period. On day 16, diabetic mice had glomerular hyperfiltration, but normal urinary albumin excretion. In conclusion, intrarenal tissue hypoxia in diabetes precedes albuminuria thereby being a plausible cause for the onset and progression of diabetic nephropathy. PMID:26936871

  4. Does lumbar facet arthrosis precede disc degeneration? A postmortem study.

    PubMed

    Eubanks, Jason David; Lee, Michael J; Cassinelli, Ezequiel; Ahn, Nicholas U

    2007-11-01

    It is believed lumbar degeneration begins in the disc, where desiccation and collapse lead to instability and compensatory facet arthrosis. We explored the contrary contention that facet degeneration precedes disc degeneration by examining 647 skeletal lumbar spines. Using facet osteophytosis as a measure of facet degeneration and vertebral rim osteophytosis as a measure of disc degeneration, we assumed bone degeneration in both locations equally reflected the progression of those in the soft tissues. We graded arthrosis Grade 0 to 4 on a continuum from no arthritis to ankylosis. The data were analyzed for different age groups to examine patterns of degeneration with age. Specimens younger than 30 years of age had a higher prevalence of facet osteophytosis compared with vertebral rim osteophotosis at L1-L2 and L2-L3. Specimens aged 30 to 39 years showed more facet osteophytosis than vertebral rim osteophytosis at L4-L5. Specimens older than 40 years, however, showed more vertebral rim osteophytosis compared with facet osteophytosis at all levels except L4-L5 and L5-S1. This skeletal study suggests facet osteophytosis appears early in the degenerative process, preceding vertebral rim osteophytosis of degenerating intervertebral discs. However, once facets begin deteriorating with age, vertebral rim osteophytosis overtakes continued facet osteophytosis. These data challenge the belief that facet osteophytosis follows vertebral rim osteophytosis; rather, it appears vertebral rim osteophytosis progresses more rapidly in later years, but facet osteophotosis occurs early, predominating in younger individuals. PMID:17767079

  5. Possible evolutionary relationships between streptomycin and bluensomycin biosynthetic pathways: detection of novel inositol kinase and O-carbamoyltransferase activities.

    PubMed Central

    Walker, J B

    1990-01-01

    Bluensomycin (glebomycin) is an aminocyclitol antibiotic that differs structurally from dihydrostreptomycin in having bluensidine (1D-1-O-carbamoyl-3-guanidinodeoxy-scyllo-inositol) rather than streptidine (1,3-diguanidino-1,3-dideoxy-scyllo-inositol) as its aminocyclitol moiety. Extracts of the bluensomycin producer Streptomyces hygroscopicus form glebosus ATCC 14607 (S. glebosus) were found to have aminodeoxy-scyllo-inositol kinase activity but to lack 1D-1-guanidino-3-amino-1,3-dideoxy-scyllo-inositol kinase activity, showing for the first time that these two reactions in streptomycin producers must be catalyzed by different enzymes. S. glebosus extracts therefore possess the same five enzymes required for synthesis of guanidinodeoxy-scyllo-inositol from myo-inositol that are found in streptomycin producers but lack the next three of the four enzymes found in streptomycin producers that are required to synthesize the second guanidino group of streptidine-P. In place of a second guanidino group, S. glebosus extracts were found to catalyze a Mg2(+)-dependent carbamoylation of guanidinodeoxy-scyllo-inositol to form bluensidine, followed by a phosphorylation to form bluensidine-P. The novel carbamoyl-P:guanidinodeoxy-scyllo-inositol O-carbamoyltransferase and ATP:bluensidine phosphotransferase activities were not detected in streptomycin producers or in S. glebosus during its early rapid growth phase. Free bluensidine appears to be a normal intermediate in bluensomycin biosynthesis, in contrast to the case of streptomycin biosynthesis; in the latter, although exogenous streptidine can enter the pathway via streptidine-P, free streptidine is not an intermediate in the endogenous biosynthetic pathway. Comparison of the streptomycin and bluensomycin biosynthetic pathways provides a unique opportunity to evaluate those proposed mechanisms for the evolutionary acquisition of new biosynthetic capabilities that involve gene duplication and subsequent mutational changes in

  6. [3H]Indole-3-acetyl-myo-inositol hydrolysis by extracts of Zea mays L. vegetative tissue

    NASA Technical Reports Server (NTRS)

    Hall, P. J.; Bandurski, R. S.

    1986-01-01

    [3H]Indole-3-acetyl-myo-inositol was hydrolyzed by buffered extracts of acetone powders prepared from 4 day shoots of dark grown Zea mays L. seedlings. The hydrolytic activity was proportional to the amount of extract added and was linear for up to 6 hours at 37 degrees C. Boiled or alcohol denatured extracts were inactive. Analysis of reaction mixtures by high performance liquid chromatography demonstrated that not all isomers of indole-3-acetyl-myo-inositol were hydrolyzed at the same rate. Buffered extracts of acetone powders were prepared from coleoptiles and mesocotyls. The rates of hydrolysis observed with coleoptile extracts were greater than those observed with mesocotyl extracts. Active extracts also catalyzed the hydrolysis of esterase substrates such as alpha-naphthyl acetate and the methyl esters of indoleacetic acid and naphthyleneacetic acid. Attempts to purify the indole-3-acetyl-myo-inositol hydrolyzing activity by chromatographic procedures resulted in only slight purification with large losses of activity. Chromatography over hydroxylapatite allowed separation of two enzymically active fractions, one of which catalyzed the hydrolysis of both indole-3-acetyl-myo-inositol and esterase substrates. With the other enzymic hydrolysis of esterase substrates was readily demonstrated, but no hydrolysis of indole-3-acetyl-myo-inositol was ever detected.

  7. Formation of inositol 1,3,4,6-tetrakisphosphate during angiotensin II action in bovine adrenal glomerulosa cells

    SciTech Connect

    Balla, T.; Guillemette, G.; Baukal, A.J.; Catt, K.J.

    1987-10-14

    Angiotensin II stimulates the formation of several inositol polyphosphates in cultured bovine adrenal glomerulosa cells prelabelled with (/sup 3/H) inositol. Analysis by high performance anion exchange chromatography of the inositol-phosphate compounds revealed the existence of two additional inositol tetrakisphosphate (InsP4) isomers in proximity to Ins-1,3,4,5-P4, the known phosphorylation product of Ins-1,4,5-trisphosphate and precursor of Ins-1,3,4-trisphosphate. Both of these new compounds showed a slow increase after stimulation with angiotensin II. The structure of one of these new InsP4 isomers, which is a phosphorylation product of Ins-1,3,4-P3, was deduced by its resistance to periodate oxidation to be Ins-1,3,4,6-P4. The existence of multiple cycles of phosphorylation-dephosphorylation reactions for the processing of Ins-1,4,5-P4 may represent a new aspect of the inositol-lipid related signalling mechanism in agonist-activated target cells.

  8. Arabidopsis inositol 1,3,4-trisphosphate 5/6 kinase 2 is required for seed coat development.

    PubMed

    Tang, Yong; Tan, Shutang; Xue, Hongwei

    2013-07-01

    Inositol 1,3,4-trisphosphate 5/6 kinase (ITPK) phosphorylates inositol 1,3,4-trisphosphate to form inositol 1,3,4,5-tetrakisphosphate and inositol 1,3,4,6-tetrakisphosphate which can be finally transferred to inositol hexaphosphate (IP₆) and play important roles during plant growth and development. There are 4 putative ITPK members in Arabidopsis. Expression pattern analysis showed that ITPK2 is constitutively expressed in various tissues. A T-DNA knockout mutant of ITPK2 was identified and scanning electron microscopy (SEM) analysis showed that the epidermis structure of seed coat was irregularly formed in seeds of itpk2-1 mutant, resulting in the increased permeability of seed coat to tetrazolium salts. Further analysis by gas chromatography coupled with mass spectrometry of lipid polyester monomers in cell wall confirmed a dramatic decrease in composition of suberin and cutin, which relate to the permeability of seed coat and the formation of which is accompanied with seed coat development. These results indicate that ITPK2 plays an essential role in seed coat development and lipid polyester barrier formation. PMID:23595027

  9. Certain Malvaceae Plants Have a Unique Accumulation of myo-Inositol 1,2,4,5,6-Pentakisphosphate

    PubMed Central

    Phillippy, Brian Q.; Perera, Imara Y.; Donahue, Janet L.; Gillaspy, Glenda E.

    2015-01-01

    Methods used to quantify inositol phosphates in seeds lack the sensitivity and specificity necessary to accurately detect the lower concentrations of these compounds contained in the leaves of many plants. In order to measure inositol hexakisphosphate (InsP6) and inositol pentakisphosphate (InsP5) levels in leaves of different plants, a method was developed to concentrate and pre-purify these compounds prior to analysis. Inositol phosphates were extracted from leaves with diluted HCl and concentrated on small anion exchange columns. Reversed-phase solid phase extraction cartridges were used to remove compounds that give peaks that sometimes interfere during HPLC. The method permitted the determination of InsP6 and InsP5 concentrations in leaves as low as 10 µM and 2 µM, respectively. Most plants analyzed contained a high ratio of InsP6 to InsP5. In contrast, certain members of the Malvaceae family, such as cotton (Gossypium) and some hibiscus (Hibiscus) species, had a preponderance of InsP5. Radiolabeling of cotton seedlings also showed increased amounts of InsP5 relative to InsP6. Why some Malvaceae species exhibit a reversal of the typical ratios of these inositol phosphates is an intriguing question for future research. PMID:27135328

  10. Asymmetric Distribution of Glucose and Indole-3-Acetyl-myo-Inositol in Geostimulated Zea mays Seedlings 1

    PubMed Central

    Momonoki, Yoshie S.

    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. PMID:11537873

  11. Certain Malvaceae Plants Have a Unique Accumulation of myo-Inositol 1,2,4,5,6-Pentakisphosphate.

    PubMed

    Phillippy, Brian Q; Perera, Imara Y; Donahue, Janet L; Gillaspy, Glenda E

    2015-01-01

    Methods used to quantify inositol phosphates in seeds lack the sensitivity and specificity necessary to accurately detect the lower concentrations of these compounds contained in the leaves of many plants. In order to measure inositol hexakisphosphate (InsP₆) and inositol pentakisphosphate (InsP₅) levels in leaves of different plants, a method was developed to concentrate and pre-purify these compounds prior to analysis. Inositol phosphates were extracted from leaves with diluted HCl and concentrated on small anion exchange columns. Reversed-phase solid phase extraction cartridges were used to remove compounds that give peaks that sometimes interfere during HPLC. The method permitted the determination of InsP₆ and InsP₅ concentrations in leaves as low as 10 µM and 2 µM, respectively. Most plants analyzed contained a high ratio of InsP₆ to InsP₅. In contrast, certain members of the Malvaceae family, such as cotton (Gossypium) and some hibiscus (Hibiscus) species, had a preponderance of InsP₅. Radiolabeling of cotton seedlings also showed increased amounts of InsP₅ relative to InsP₆. Why some Malvaceae species exhibit a reversal of the typical ratios of these inositol phosphates is an intriguing question for future research. PMID:27135328

  12. Skeletal Muscle Phospholipid Metabolism Regulates Insulin Sensitivity and Contractile Function.

    PubMed

    Funai, Katsuhiko; Lodhi, Irfan J; Spears, Larry D; Yin, Li; Song, Haowei; Klein, Samuel; Semenkovich, Clay F

    2016-02-01

    Skeletal muscle insulin resistance is an early defect in the development of type 2 diabetes. Lipid overload induces insulin resistance in muscle and alters the composition of the sarcoplasmic reticulum (SR). To test the hypothesis that skeletal muscle phospholipid metabolism regulates systemic glucose metabolism, we perturbed choline/ethanolamine phosphotransferase 1 (CEPT1), the terminal enzyme in the Kennedy pathway of phospholipid synthesis. In C2C12 cells, CEPT1 knockdown altered SR phospholipid composition and calcium flux. In mice, diet-induced obesity, which decreases insulin sensitivity, increased muscle CEPT1 expression. In high-fat diet-fed mice with skeletal muscle-specific knockout of CEPT1, systemic and muscle-based approaches demonstrated increased muscle insulin sensitivity. In CEPT1-deficient muscles, an altered SR phospholipid milieu decreased sarco/endoplasmic reticulum Ca(2+) ATPase-dependent calcium uptake, activating calcium-signaling pathways known to improve insulin sensitivity. Altered muscle SR calcium handling also rendered these mice exercise intolerant. In obese humans, surgery-induced weight loss increased insulin sensitivity and decreased skeletal muscle CEPT1 protein. In obese humans spanning a spectrum of metabolic health, muscle CEPT1 mRNA was inversely correlated with insulin sensitivity. These results suggest that high-fat feeding and obesity induce CEPT1, which remodels the SR to preserve contractile function at the expense of insulin sensitivity. PMID:26512026

  13. Comparative Phospholipid Profiles of Control and Glaucomatous Human Trabecular Meshwork

    PubMed Central

    Aribindi, Katyayini; Guerra, Yenifer; Lee, Richard K.; Bhattacharya, Sanjoy K.

    2013-01-01

    Purpose. We compared phospholipid (phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and phosphatidylinositol) profiles of control and glaucomatous trabecular meshwork (TM) derived from human donors. Methods. Control TM and most primary open angle glaucoma (POAG) TM were collected from cadaver donors. A select subset of POAG surgical TM samples also were collected for analyses. Lipid extraction was performed using a modification of the Bligh and Dyer method, protein concentrations were determined using the Bradford method, and for select samples confirmed with densitometry of PHAST gels. Lipids were identified and subjected to ratiometric quantification using a TSQ quantum Access Max triple quadrupole mass spectrometer with precursor ion scan (PIS) or neutral ion loss scan (NLS), using appropriate class specific lipid standards. Results. The comparative profiles of phosphatidylcholine, phosphatidylserine, phosphoethanolamine, and phosphatidylinositol between control and glaucomatous TM showed several species common between them. A number of unique lipids in all four phospholipid classes also were identified in control TM that were absent in glaucoma TM and vice versa. Conclusions. A number of phospholipids were found to be uniquely present in control but absent in glaucomatous TM and vice versa. Compared to a previous study of control and POAG blood, a number of these phospholipids are absent locally (TM), as well as systemically (in blood). PMID:23557733

  14. Synthetic phospholipids as specific substrates for plasma endothelial lipase.

    PubMed

    Papillon, Julien P N; Pan, Meihui; Brousseau, Margaret E; Gilchrist, Mark A; Lou, Changgang; Singh, Alok K; Stawicki, Todd; Thompson, James E

    2016-08-01

    We designed and prepared synthetic phospholipids that generate lyso-phosphatidylcholine products with a unique mass for convenient detection by LC-MS in complex biological matrices. We demonstrated that compound 4, formulated either as a Triton X-100 emulsion or incorporated in synthetic HDL particles can serve as a substrate for plasma EL with useful specificity. PMID:27344207

  15. Porphyrin–phospholipid liposomes permeabilized by near-infrared light

    PubMed Central

    Carter, Kevin A.; Shao, Shuai; Hoopes, Matthew I.; Luo, Dandan; Ahsan, Bilal; Grigoryants, Vladimir M.; Song, Wentao; Huang, Haoyuan; Zhang, Guojian; Pandey, Ravindra K.; Geng, Jumin; Pfeifer, Blaine A.; Scholes, Charles P.; Ortega, Joaquin; Karttunen, Mikko; Lovell, Jonathan F.

    2014-01-01

    The delivery of therapeutic compounds to target tissues is a central challenge in treating disease. Externally controlled drug release systems hold potential to selectively enhance localized delivery. Here we describe liposomes doped with porphyrin–phospholipid that are permeabilized directly by near-infrared light. Molecular dynamics simulations identified a novel light-absorbing monomer esterified from clinically approved components predicted and experimentally demonstrated to give rise to a more stable porphyrin bilayer. Light-induced membrane permeabilization is enabled with liposomal inclusion of 10 molar % porphyrin–phospholipid and occurs in the absence of bulk or nanoscale heating. Liposomes reseal following laser exposure and permeability is modulated by varying porphyrin–phospholipid doping, irradiation intensity or irradiation duration. Porphyrin–phospholipid liposomes demonstrate spatial control of release of entrapped gentamicin and temporal control of release of entrapped fluorophores following intratumoral injection. Following systemic administration, laser irradiation enhances deposition of actively loaded doxorubicin in mouse xenografts, enabling an effective single-treatment antitumour therapy. PMID:24699423

  16. Structural intermediates during α-synuclein fibrillogenesis on phospholipid vesicles

    PubMed Central

    Comellas, Gemma; Lemkau, Luisel R.; Zhou, Donghua H.; George, Julia M.

    2012-01-01

    α-Synuclein (AS) fibrils are the main protein component of Lewy Bodies, the pathological hallmark of Parkinson’s disease and other related disorders. AS forms helices that bind phospholipid membranes with high affinity, but no atomic level data for AS aggregation in the presence of lipids is yet available. Here, we present direct evidence of a conversion from α-helical conformation to β-sheet fibrils in the presence of anionic phospholipid vesicles and direct conversion to β-sheet fibrils in their absence. We have trapped intermediate states throughout the fibril formation pathways to examine the structural changes using solid-state NMR spectroscopy and electron microscopy. The comparison between mature AS fibrils formed in aqueous buffer and those derived in the presence of anionic phospholipids demonstrates no major changes in the overall fibril fold. However, a site-specific comparison of these fibrillar states demonstrates major perturbations in the N-terminal domain with a partial disruption of the long β-strand located in the 40’s and small perturbations in residues located in the “non-β amyloid component” (NAC) domain. Combining all these results, we propose a model for AS fibrillogenesis in the presence of phospholipid vesicles. PMID:22352310

  17. Hexamodal imaging with porphyrin-phospholipid-coated upconversion nanoparticles.

    PubMed

    Rieffel, James; Chen, Feng; Kim, Jeesu; Chen, Guanying; Shao, Wei; Shao, Shuai; Chitgupi, Upendra; Hernandez, Reinier; Graves, Stephen A; Nickles, Robert J; Prasad, Paras N; Kim, Chulhong; Cai, Weibo; Lovell, Jonathan F

    2015-03-11

    Hexamodal imaging using simple nanoparticles is demonstrated. Porphyrin-phospholipids are used to coat upconversion nanoparticles in order to generate a new biocompatible material. The nanoparticles are characterized in vitro and in vivo for imaging via fluorescence, upconversion, positron emission tomography, computed tomography, Cerenkov luminescence, and photoacoustic tomography. PMID:25640213

  18. Porphyrin-phospholipid liposomes permeabilized by near-infrared light.

    PubMed

    Carter, Kevin A; Shao, Shuai; Hoopes, Matthew I; Luo, Dandan; Ahsan, Bilal; Grigoryants, Vladimir M; Song, Wentao; Huang, Haoyuan; Zhang, Guojian; Pandey, Ravindra K; Geng, Jumin; Pfeifer, Blaine A; Scholes, Charles P; Ortega, Joaquin; Karttunen, Mikko; Lovell, Jonathan F

    2014-01-01

    The delivery of therapeutic compounds to target tissues is a central challenge in treating disease. Externally controlled drug release systems hold potential to selectively enhance localized delivery. Here we describe liposomes doped with porphyrin-phospholipid that are permeabilized directly by near-infrared light. Molecular dynamics simulations identified a novel light-absorbing monomer esterified from clinically approved components predicted and experimentally demonstrated to give rise to a more stable porphyrin bilayer. Light-induced membrane permeabilization is enabled with liposomal inclusion of 10 molar % porphyrin-phospholipid and occurs in the absence of bulk or nanoscale heating. Liposomes reseal following laser exposure and permeability is modulated by varying porphyrin-phospholipid doping, irradiation intensity or irradiation duration. Porphyrin-phospholipid liposomes demonstrate spatial control of release of entrapped gentamicin and temporal control of release of entrapped fluorophores following intratumoral injection. Following systemic administration, laser irradiation enhances deposition of actively loaded doxorubicin in mouse xenografts, enabling an effective single-treatment antitumour therapy. PMID:24699423

  19. 21 CFR 862.1575 - Phospholipid test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Phospholipid test system. 862.1575 Section 862.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... treatment of disorders involving lipid (fat) metabolism. (b) Classification. Class I (general controls)....

  20. 21 CFR 862.1575 - Phospholipid test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Phospholipid test system. 862.1575 Section 862.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... treatment of disorders involving lipid (fat) metabolism. (b) Classification. Class I (general controls)....

  1. Lysosomal phospholipids from rat liver after treatment with different drugs.

    PubMed

    Tjiong, H B; Lepthin, J; Debuch, H

    1978-01-01

    Rats were treated with 5 different drugs p-ethoxyacetanilide (I), indometacin (II) and nor-amidopyrine-methanesulfonate (III), O,O'-bis(diethylaminoethyl)hexestrol(IV) and choloroquine (V) for 3 - 4 weeks. Liver cell fractions were isolated by discontinuous gradient centrifugation and the specific activity of acid phosphatase was determined in each. Lysosomal fractions contained widely varying amounts of this marker enzyme, indicating that the concentration of lysosomes within these fractions differed. The amounts and patterns of phospholipids reflected this fact. Since we assumed bis(monoacylglycero)phosphate [(MAG)2-P; synonym:lysobisphosphatidic acid] is a marker lipid for secondary lysosomes, we expected and found significant quantities of this acidic phospholipid only in those lysosomal fractions which were also rich in acid phosphatase activity. 12% of the lysosomal phospholipids from animals receiving the hexestrol derivative (IV), and 19% of those from the chloroquine (V) experiment were present as (MAG)2P. The fatty acid compositions of this lysosomal phospholipid were not the same in all lysosome fractions. The more (MAG)2P present in the lysosomes, the more unsaturated are the fatty acids. Thus, after treatment with chloroquine, more than 90% of the fatty acids from (MAG)2P are unsaturated; C22:6 represents about 70% of the total. PMID:627402

  2. 21 CFR 862.1575 - Phospholipid test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... treatment of disorders involving lipid (fat) metabolism. (b) Classification. Class I (general controls). The... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Phospholipid test system. 862.1575 Section 862.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  3. 21 CFR 862.1575 - Phospholipid test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... treatment of disorders involving lipid (fat) metabolism. (b) Classification. Class I (general controls). The... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Phospholipid test system. 862.1575 Section 862.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  4. 21 CFR 862.1575 - Phospholipid test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... treatment of disorders involving lipid (fat) metabolism. (b) Classification. Class I (general controls). The... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Phospholipid test system. 862.1575 Section 862.1575 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...

  5. Temperature Control of Phospholipid Biosynthesis in Escherichia coli

    PubMed Central

    Sinensky, Michael

    1971-01-01

    The higher the growth temperature of Escherichia coli cultures the greater is the proportion of saturated fatty acids in the bacterial phospholipids. When fatty acids are exogenously supplied to E. coli, higher growth temperatures will likewise increase the relative incorporation of saturated fatty acids into phospholipids. One of the steps in the utilization of fatty acids for phospholipid biosynthesis is, therefore, temperature-controlled. The temperature effect observed in vivo with mixtures of 3H-oleate and 14C-palmitate is demonstrable in vitro by using mixtures of the coenzyme A derivative of these fatty acids for the acylation of α-glycerol phosphate to lysophosphatidic and phosphatidic acids. In E. coli extracts, the relative rates of transacylation of palmityl and oleyl coenzyme A vary as a function of incubation temperature in a manner which mimics the temperature control observed in vivo. The phosphatidic acid synthesized in vitro shows a striking enrichment of oleate at the β position analogous to the positional specificity observed in phospholipids synthesized in vivo. PMID:4324806

  6. Phospholipid Motional Characteristics in a Dry Biological System 1

    PubMed Central

    Priestley, David A.; de Kruijff, B.

    1982-01-01

    Analysis of the proton-decoupled 31P-nuclear magnetic resonance (NMR) spectrum of fully hydrated Typha latifolia pollen revealed the presence of two main peaks: A broad asymmetrical component of a `bilayer' lineshape and a much narrower symmetrical component originating from phosphorus compounds undergoing rapid isotropic motion. From (a) 31P-NMR experiments on the hydrated total pollen phospholipids, (b) saturation transfer 31P-NMR experiments, and (c) the fraction of lipid phosphate in the pollen, it can be concluded that the great majority of the endogenous phospholipids are arranged in extended bilayers in which the lipid phosphates undergo fast (τc < 10−6 second) long axis rotation. This bilayer arrangement of phospholipids was observed in the pollen down to hydration levels of at least 10.9% moisture content. At the lowest level of pollen hydration examined (5.2%) the 31P-NMR spectrum had a solid state lineshape demonstrating that all the phosphorus-containing compounds (including the phospholipids) were virtually immobile. PMID:16662616

  7. An improved SPE method for fractionation and identification of phospholipids.

    PubMed

    Fauland, Alexander; Trötzmüller, Martin; Eberl, Anita; Afiuni-Zadeh, Somaieh; Köfeler, Harald; Guo, Xinghua; Lankmayr, Ernst

    2013-02-01

    This work reports an efficient and universal SPE method developed for separation and identification of phospholipids derived from complex biological samples. For the separation step, sequential combination of silica gel-aminopropyl-silica gel SPE cartridges is applied. This setup enables separation of phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, phosphatidylinositol, phosphatidylserine, cardiolipin, and sphingomyelin into four fractions according to the polarity of their headgroups. Sample acquisition of the SPE fractions is performed by a high-resolution LC-MS system consisting of a hybrid linear IT Fourier transform ion cyclotron resonance mass spectrometer coupled to RP-HPLC. The unequivocal advantage of our SPE sample preparation setup is avoidance of analyte peak overlapping in the determination step done by RP-HPLC. Overlapping phospholipid signals would otherwise exert adverse ion suppression effects. An additional benefit of this method is the elimination of polar and nonpolar (e.g. neutral lipids) contaminants from the phospholipid fractions, which highly reduces contamination of the LC-MS system. The method was validated with fermentation samples of organic waste, where 78 distinct phospholipid and sphingomyelin species belonging to six lipid classes were successfully identified. PMID:23349108

  8. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    EPA Science Inventory

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  9. Effect of atropine and gammahydroxybutyrate on ischemically induced changes in the level of radioactivity in (/sup 3/H)inositol phosphates in gerbil brain in vivo

    SciTech Connect

    Wikiel, H.; Halat, G.; Strosznajder, J.

    1988-05-01

    Brain ischemia in gerbils was induced by ligation of both common carotid arteries for 1 min or 10 min. Sham-operated animals served as controls. Intracerebral injection of (3H)inositol into gerbil brain 16 hr before ischemic insult resulted in equilibration of the label between inositol lipids and water-soluble inositol phosphate. A short ischemic period (1 min) resulted in a statistically significant increase in the radioactivity of inositol triphosphate (IP3) and inositol monophosphate (IP), by about 48% and 79%, respectively, with little change in that of the intermediate inositol biphosphate (IP2), which increased by about 16%. When the ischemic period was prolonged (10 min), an increase in the radioactivity of inositol monophosphate exclusively, by about 84%, was observed. The level of radioactivity in inositol phosphates IP2 and IP3 decreased by about 50%, probably as a consequence of phosphatase activation by the ischemic insult. The agonist of the cholinergic receptor, carbachol, injected intracerebrally (40 micrograms per animal) increased accumulation of radioactivity in all inositol phosphates. The level of radioactivity in IP3, IP2, and IP was elevated by about 40, 23, and 147%, respectively. The muscarinic cholinergic antagonist, atropine, injected intraperitoneally in doses of 100 mg/kg body wt. depressed phosphoinositide metabolism in control animals. The level of radioactivity in water-soluble inositol metabolites in the brain of animals pretreated with atropine was evidently about 32% lower than in untreated animals. Pretreatment with atropine decreased the radioactivity of all inositol phosphates in the brain of animals subjected to 1-min ischemia and the radioactivity of IP in the case of 10-min brain ischemia.

  10. Production of inositol trisphosphates upon. cap alpha. -adrenergic stimulation in BC3H-1 muscle cells

    SciTech Connect

    Ambler, S.K.; Thompson, B.; Brown, J.H.; Taylor, P.

    1986-05-01

    Activation of ..cap alpha../sub 1/-adrenergic receptors in BC3H-1 muscle cells rapidly mobilizes intracellular and results in a paradoxically slower accumulation of inositol trisphosphate. A possible explanation for this discrepancy may be provided by the recent findings of Irvine et al. of additional Ins P3 isomers besides the Ca/sup + +/-mobilizing isomer, Ins 1,4,5-P3. They have eluted and separated the inositol phosphates of BC3H-1 cells with an NH/sub 4//sup +/ x HCO/sub 2//sup -//H/sub 3/PO/sub 4/ gradient on a Whatman Partisil 10SAX column using Hewlett-Packard HPLC. Commercial (/sup 3/H)Ins 1,4,5-P3 and (/sup 3/H)inositol phosphates from carbachol-stimulated parotid glands were used as standards. Little or no Ins 1,3,4-P3 could be detected in control or phenylephrine-treated BC3H-1 cells. Ins 1,4,5-P3 followed the pattern of agonist stimulation observed previously. As a positive control, Ins P3 isomers were also measured in 1321N1 astrocytoma cells. Muscarinic stimulation of 1321N1 cells results in both the rapid accumulation of Ins P3 and Ca/sup + +/ mobilization. There is no detectable basal Ins 1,3,4-P3, but carbachol stimulates a rapid production of this compound in 1321N1 cells. Agonist activation also results in a rapid increase in Ins 1,4,5-P3 above basal values. These studies indicate that Ins 1,3,4-P3 does not contribute to the InsP3 signal in BC3H-1 cells and multiple mechanisms may exist for the coupling of receptors to PI turnover.

  11. Fungal Inositol Pyrophosphate IP7 Is Crucial for Metabolic Adaptation to the Host Environment and Pathogenicity

    PubMed Central

    Lev, Sophie; Li, Cecilia; Desmarini, Desmarini; Saiardi, Adolfo; Fewings, Nicole L.; Schibeci, Stephen D.; Sharma, Raghwa; Sorrell, Tania C.

    2015-01-01

    ABSTRACT Inositol pyrophosphates (PP-IPs) comprising inositol, phosphate, and pyrophosphate (PP) are essential for multiple functions in eukaryotes. Their role in fungal pathogens has never been addressed. Cryptococcus neoformans is a model pathogenic fungus causing life-threatening meningoencephalitis. We investigate the cryptococcal kinases responsible for the production of PP-IPs (IP7/IP8) and the hierarchy of PP-IP importance in pathogenicity. Using gene deletion and inositol polyphosphate profiling, we identified Kcs1 as the major IP6 kinase (producing IP7) and Asp1 as an IP7 kinase (producing IP8). We show that Kcs1-derived IP7 is the most crucial PP-IP for cryptococcal drug susceptibility and the production of virulence determinants. In particular, Kcs1 kinase activity is essential for cryptococcal infection of mouse lungs, as reduced fungal burdens were observed in the absence of Kcs1 or when Kcs1 was catalytically inactive. Transcriptome and carbon source utilization analysis suggested that compromised growth of the KCS1 deletion strain (Δkcs1 mutant) in the low-glucose environment of the host lung is due to its inability to utilize alternative carbon sources. Despite this metabolic defect, the Δkcs1 mutant established persistent, low-level asymptomatic pulmonary infection but failed to elicit a strong immune response in vivo and in vitro and was not readily phagocytosed by primary or immortalized monocytes. Reduced recognition of the Δkcs1 cells by monocytes correlated with reduced exposure of mannoproteins on the Δkcs1 mutant cell surface. We conclude that IP7 is essential for fungal metabolic adaptation to the host environment, immune recognition, and pathogenicity. PMID:26037119

  12. Prefrontal inositol levels and implicit decision-making in healthy individuals and depressed patients.

    PubMed

    Jollant, Fabrice; Richard-Devantoy, Stéphane; Ding, Yang; Turecki, Gustavo; Bechara, Antoine; Near, Jamie

    2016-08-01

    Risky decision-making is found in several mental disorders and is associated with deleterious consequences. Current research aims at understanding the biological underpinnings of this complex cognitive function and the basis of individual variability. We used 3T proton Magnetic Resonance Spectroscopy to measure in vivo glutamate, GABA, N-acetyl-aspartate (NAA), and myo-inositol levels at rest in the right dorsal prefrontal cortex of 54 participants, comprising 24 unmedicated depressed patients and 30 healthy individuals. Participants were also tested with the Iowa Gambling Task (IGT), a classical measure of value-based decision-making. No group differences were found in terms of compound levels or decision-making performance. However, high inositol levels were associated with lower decision-making scores independently from group, notably during the initial stage of the task when explicit rules are still unknown and decisions are largely based on implicit processes (whole sample: F=4.0; p=0.02), with a large effect size (Cohen׳s d=0.8, 95% [0.2-1.5]). This effect was stronger when explicit knowledge was taken into account, with explicit knowledge showing an independent effect on performance. There was no association with other compounds. This study suggests, for the first time, a role for the inositol pathway on the implicit learning component of decision-making, without any direct effect on the explicit component. Hypothesized mechanisms implicate intracellular calcium modulation and subsequent synaptic plasticity. These findings represent a first step in the understanding of the biochemical mechanisms underlying decision-making and the identification of therapeutic targets. They also emphasize a dimensional approach in the study of the neurobiological determinants of mental disorders. PMID:27342631

  13. Inositol Metabolism in Plants. IV. Biosynthesis of Apiose in Lemna and Petroselinum

    PubMed Central

    Roberts, R. M.; Shah, R. H.; Loewus, F.

    1967-01-01

    The biosynthesis of apiose was investigated in cell wall polysaccharide of Lemna gibba G3 (duckweed) and in detached leaves of Petroselinum crispum (parsley). Lemna grown either in short days or in continuous light incorporated 14C from a medium containing myo-inositol-2-14C into d-apiosyl and d-xylosyl units of cell wall polysaccharides. Labeled d-apiose was characterized by paper chromatography, by formation of labeled crystalline di-O-isopropylidene d-apiose, and by gas chromatography of trimethylsilyl derivatives of apiose and of its sodium borohydride reduction product, apiitol. Periodate oxidation of labeled apiose revealed 86 to 94% of the 14C was located in formaldehyde fragments corresponding to C3′ and C4. Comparison of this result with work reported by Grisebach and Doebereiner and by Beck and Kandler supports the conclusion that myo-inositol-2-14C was converted to d-apiose labeled specifically at C4. When l-arabinose-l-14C was supplied to Lemna, both l-arabinosyl and d-xylosyl units of cell wall polysaccharides became labeled, but no 14C was found in d-apiose. Analysis of the medium external to the plants revealed the presence of a polysaccharide-like polymer that also contained labeled xylose and arabinose. Petroselinum leaves utilized myo-inositol-2-3H for the synthesis of apiose in apiin. These results provide direct evidence for a pathway of apiose biosynthesis involving d-glucuronic acid metabolism. PMID:16656551

  14. Inositol-trisphosphate reduces alveolar apoptosis and pulmonary edema in neonatal lung injury.

    PubMed

    Preuss, Stefanie; Stadelmann, Sabrina; Omam, Friede D; Scheiermann, Julia; Winoto-Morbach, Supandi; von Bismarck, Philipp; Knerlich-Lukoschus, Friederike; Lex, Dennis; Adam-Klages, Sabine; Wesch, Daniela; Held-Feindt, Janka; Uhlig, Stefan; Schütze, Stefan; Krause, Martin F

    2012-08-01

    D-myo-inositol-1,2,6-trisphosphate (IP3) is an isomer of the naturally occurring second messenger D-myo-inositol-1,4,5-trisphosphate, and exerts anti-inflammatory and antiedematous effects in the lung. Myo-inositol (Inos) is a component of IP3, and is thought to play an important role in the prevention of neonatal pulmonary diseases such as bronchopulmonary dysplasia and neonatal acute lung injury (nALI). Inflammatory lung diseases are characterized by augmented acid sphingomyelinase (aSMase) activity leading to ceramide production, a pathway that promotes increased vascular permeability, apoptosis, and surfactant alterations. A novel, clinically relevant triple-hit model of nALI was developed, consisting of repeated airway lavage, injurious ventilation, and lipopolysaccharide instillation into the airways, every 24 hours. Thirty-five piglets were randomized to one of four treatment protocols: control (no intervention), surfactant alone, surfactant + Inos, and surfactant + IP3. After 72 hours of mechanical ventilation, lungs were excised from the thorax for subsequent analyses. Clinically, oxygenation and ventilation improved, and extravascular lung water decreased significantly with the S + IP3 intervention. In pulmonary tissue, we observed decreased aSMase activity and ceramide concentrations, decreased caspase-8 concentrations, reduced alveolar epithelial apoptosis, the reduced expression of interleukin-6, transforming growth factor-β1, and amphiregulin (an epithelial growth factor), reduced migration of blood-borne cells and particularly of CD14(+)/18(+) cells (macrophages) into the airspaces, and lower surfactant surface tensions in S + IP3-treated but not in S + Inos-treated piglets. We conclude that the admixture of IP3 to surfactant, but not of Inos, improves gas exchange and edema in our nALI model by the suppression of the governing enzyme aSMase, and that this treatment deserves clinical evaluation. PMID:22403805

  15. Is inositol (1,3,4,5)-tetrakisphosphate a new second messenger

    SciTech Connect

    Hansen, C.A.; Williamson, J.R.

    1986-05-01

    Hormone-stimulated hydrolysis of inositol (Ins) lipids results in the rapid formation of Ins(1,4,5)P/sub 3/, the second messenger for intracellular Ca/sup 2 +/ mobilization. Recently, a more polar inositol phosphate, Ins(1,3,4,5)P/sub 4/ as well as its probable hydrolysis product Ins(1,3,4)P/sub 3/ have been reported to accumulate in carbachol-stimulated brain slices. Vasopressin addition to hepatocytes prelabeled with (/sup 3/H)-Ins also showed a rapid increase of Ins(1,3,4,5)P/sub 4/, which was similar to that of Ins(1,4,5)P/sub 3/, while the accumulation of Ins(1,3,4)P/sub 3/ was slower. In order to examine whether Ins(1,3,4,5)P/sub 4/ has any functional effects on Ca/sup 2 +/ homeostasis, it was synthesized enzymatically from (/sup 3/H)-Ins(1,4,5)P/sub 3/ using a partially purified phosphoinositol kinase activity from rat brain cortex. (/sup 3/H)-labeled inositol phosphates were separated by anion exchange chromatography and analyzed by HPLC using ammonium formate/phosphoric acid gradient elution. Preliminary experiments indicate that Ins(1,3,4,5)P/sub 4/ up to 10 ..mu..M does not release Ca/sup 2 +/ from vesicular pools in saponin-permeabilized hepatocytes. It has a slight inhibitory effect on Ins(1,4,5)P/sub 3/-induced Ca/sup 2 +/ release. The effect of Ins(1,3,4,5)P/sub 4/ on plasma membrane Ca/sup 2 +/ fluxes are presently being investigated.

  16. Sponge mesoporous silica formation using disordered phospholipid bilayers as template.

    PubMed

    Galarneau, Anne; Sartori, Federica; Cangiotti, Michela; Mineva, Tzonka; Di Renzo, Francesco; Ottaviani, M Francesca

    2010-02-18

    Lecithin/dodecylamine/lactose mixtures in ethanol/aqueous media led to the formation of sponge mesoporous silica (SMS) materials by means of tetraethoxysilane (TEOS) as silica source. SMS materials show a "sponge-mesoporous" porosity with a pore diameter of about 5-6 nm, in accordance to the length of a lecithin bilayer. SMS synthesis was developed to create a new class of powerful biocatalysts able to efficiently encapsulate enzymes by adding a porosity control to the classical sol-gel synthesis and by using phospholipids and lactose as protecting agents for the enzymes. In the present study, the formation of SMS was investigated by using electron paramagnetic resonance (EPR) probes inserted inside phospholipid bilayers. The influence of progressive addition of each component (ethanol, dodecylamine, lactose, TEOS) on phospholipid bilayers was first examined; then, the time evolution of EPR spectra during SMS synthesis was studied. Parameters informative of mobility, structure, order, and polarity around the probes were extracted by computer analysis of the EPR line shape. The results were discussed on the basis of solids characterization by X-ray diffraction, nitrogen isotherm, transmission electron microscopy, and scanning electron microscopy. The results, together with the well-known ability of ethanol to promote membrane hemifusion, suggested that the templating structure is a bicontinuous phospholipid bilayer phase, shaped as a gyroid, resulting of multiple membrane hemifusions induced by the high alcohol content used in SMS synthesis. SMS synthesis was compared to hexagonal mesoporous silica (HMS) synthesis accomplished by adding TEOS to a dodecylamine/EtOH/water mixture. EPR evidenced the difference between HMS and SMS synthesis; the latter uses an already organized but slowly growing mesophase of phospholipids, never observed before, whereas the former shows a progressive elongation of micelles into wormlike structures. SMS-type materials represent a new

  17. Calcium-phospholipid enhanced protein phosphorylation in human placenta

    SciTech Connect

    Moore, J.J.; Moore, R.; Cardaman, R.C.

    1986-07-01

    Calcium-activated, phospholipid-dependent protein phosphorylation has not been studied in placenta. Human placental cytosol was subjected to an endogenous protein phosphorylation assay using (..gamma..-/sup 32/P)ATP in the presence of calcium and phosphatidylserine. Protein phosphorylation was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. When compared to basal levels, calcium (10/sup -6/ M) in combination with phosphatidylserine (50 ..mu..g/ml) significantly enhanced (P < 100) /sup 32/P incorporation into phosphoproteins having mol wt 47,000, 43,000, and 37,000. Half-maximal /sup 22/P incorporation was observed with 3.5 x 10/sup -7/ M Ca/sup 2 +/ in the presence of phosphatidylserine (50 ..mu..g/ml). The effect of phosphatidylserine was biphasic. In the presence of Ca 10/sup -6/ M, /sup 32/P incorporation increased to a maximum at 70 /sup +/g/ml of phosphatidylserine. The increase was suppressed at 150 ..mu..g/ml. Tetracaine caused a dose-dependent inhibition of calcium-activated, phospholipid-dependent enhancement of the three phosphoproteins. Calcium in the absence of phospholipid enhanced the phosphorylation of a protein of 98,000 mol wt. Phosphatidylserine suppressed this enhancement. Calmodulin (10/sup -6/ M) had no detectable effect upon phosphorylation beyond that of calcium alone, but the calmodulin inhibitor R-24571 specifically inhibited the calcium-stimulated 98,000 mol wt phosphoprotein. Calcium-activated, phospholipid-dependent phospholipid-dependent phosphoproteins are present in human placental cytosol; whether calcium-activated, calmodulin-dependent phosphoproteins also are present remains a question.

  18. Binding of Diphtheria Toxin to Phospholipids in Liposomes

    NASA Astrophysics Data System (ADS)

    Alving, Carl R.; Iglewski, Barbara H.; Urban, Katharine A.; Moss, Joel; Richards, Roberta L.; Sadoff, Jerald C.

    1980-04-01

    Diphtheria toxin bound to the phosphate portion of some, but not all, phospholipids in liposomes. Liposomes consisting of dimyristoyl phosphatidylcholine and cholesterol did not bind toxin. Addition of 20 mol% (compared to dimyristoyl phosphatidylcholine) of dipalmitoyl phosphatidic acid, dicetyl phosphate, phosphatidylinositol phosphate, cardiolipin, or phosphatidylserine in the liposomes resulted in substantial binding of toxin. Inclusion of phosphatidylinositol in dimyristol phosphatidylcholine / cholesterol liposomes did not result in toxin binding. The calcium salt of dipalmitoyl phosphatidic acid was more effective than the sodium salt, and the highest level of binding occurred with liposomes consisting only of dipalmitoyl phosphatidic acid (calcium salt) and cholesterol. Binding of toxin to liposomes was dependent on pH, and the pattern of pH dependence varied with liposomes having different compositions. Incubation of diphtheria toxin with liposomes containing dicetyl phosphate resulted in maximal binding at pH 3.6, whereas binding to liposomes containing phosphatidylinositol phosphate was maximal above pH 7. Toxin did not bind to liposomes containing 20 mol% of a free fatty acid (palmitic acid) or a sulfated lipid (3-sulfogalactosylceramide). Toxin binding to dicetyl phosphate or phosphatidylinositol phosphate was inhibited by UTP, ATP, phosphocholine, or p-nitrophenyl phosphate, but not by uracil. We conclude that (a) diphtheria toxin binds specifically to the phosphate portion of certain phospholipids, (b) binding to phospholipids in liposomes is dependent on pH, but is not due only to electrostatic interaction, and (c) binding may be strongly influenced by the composition of adjacent phospholipids that do not bind toxin. We propose that a minor membrane phospholipid (such as phosphatidylinositol phosphate or phosphatidic acid), or that some other phosphorylated membrane molecule (such as a phosphoprotein) may be important in the initial binding of

  19. Phospholipid transfer from vesicles to high density lipoproteins, catalyzed by human plasma phospholipid transfer protein

    SciTech Connect

    Sweeny, S.A.

    1985-01-01

    Human plasma phospholipid transfer protein (PLTP) catalyzes the mass transfer of phosphatidylcholine (PC). Partial purification of PLTP yielded proteins with apparent M/sub r/ = 59,000 and 40,000 by SDS-PAGE. PLTP activity was measured by transfer of (/sup 14/C)L-..cap alpha..-dipalmitoyl PC from egg-PC vesicles to HDL. Activity was enhanced at low pH (4.5) upon addition of ..beta..-mercaptoethanol while Ca/sup +2/ and Na/sup +/ had no effect. E/sub act/ for facilitated PC transfer was 18.2 +/- 2 kcal/mol. The donor specificity of PLTP was examined using vesicles containing egg-PC plus cholesterol or sphingomyelin. The fluidity of the donor membrane (measured by fluorescence polarization of diphenylhexatriene) correlated strongly with a decrease in PLTP activity. Phosphatidic acid did not affect activity. Increase in vesicle size reduced activity. The acceptor specificity of PLTP was examined using chemically modified HDL. PLTP activity increased up to 1.7-fold with an initial increase in negative charge and then decreased upon extensive modification. A mechanism is proposed where PLTP binds to vesicls and enhances the diffusion of PC into the medium where it is adsorbed by HDL.

  20. Changes in autonomic activity preceding onset of nonsustained ventricular tachycardia

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Sasabe, N.; Atarashi, H.; Katoh, T.; Hayakawa, H.; Cohen, R. J.

    1996-01-01

    Background: The triggering role of the autonomic nervous system in the initiation of ventricular tachycardia has not been established. To investigate the relationship between changes in autonomic activity and the occurrence of nonsustained ventricular tachycardia (NSVT) we examined heart rate variability (HRV) during the 2-hour period preceding spontaneous episodes of NSVT. Twenty-four subjects were identified retrospectively as having had one episode of NSVT during 24-hour Holter ECC recording. Methods: We measured the mean interval between normal heats (meanRR), the standard deviation of the intervals between beats (SD), the percentage of counts of sequential intervals between normal beats with a change of >50 ms (%RR50), the logarithms of low- and high-frequency spectral components (lnLF, lnHF) of HRV for sequential 10-minute segments preceding NSVT. The correlation dimension (CDim) of HRV was calculated similarly for sequential 20-minute segments. We assessed the significance of the time-course change of each marker over the 120-minute period prior to NSVT onset. Results: MeanRR (P < 0.05), lnLF (P < 0.0001), lnHF (P < 0.0001), the natural logarithm of the ratio of LF to HF (ln[LF/HF]; P < 0.05), and CDim (P < 0.05) showed significant time-course changes during that period, while SD and %RR50 did not. MeanRR, lnLF, lnHF, and CDim all decreased prior to the onset of NSVT, whereas ln(LF/HF) increased. We divided the subjects into two groups: one consisting of 12 patients with coronary artery disease; and the second group of 12 patients without known coronary artery disease. Both groups showed significant changes (P < 0.05) of CDim, lnLF, and lnHF preceding the episodes of NSVT. Conclusions: Changes in the pattern of HRV prior to the onset of episodes of NSVT suggest that changes in autonomic activity may commonly play a role in the triggering of spontaneous episodes of NSVT in susceptible patients. The measured changes suggest a reduction in parasympathetic

  1. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  2. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  3. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  4. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  5. 22 CFR 42.68 - Informal evaluation of family members if principal applicant precedes them.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... principal applicant precedes them. 42.68 Section 42.68 Foreign Relations DEPARTMENT OF STATE VISAS VISAS... Visas § 42.68 Informal evaluation of family members if principal applicant precedes them. (a) Preliminary determination of visa eligibility. If a principal applicant proposes to precede the family to...

  6. Decision Preceding Negativity in the Iowa Gambling Task: An ERP study

    ERIC Educational Resources Information Center

    Bianchin, Marta; Angrilli, Alessandro

    2011-01-01

    The present study aimed to investigate the slow negative potential (termed Decision Preceding Negativity, DPN, from the family of the Readiness Potential) which precedes a willed risky decision. To this end, evoked potentials preceding and following an economic choice were measured in a sample of 16 male students during the Iowa Gambling Task…

  7. Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue

    NASA Technical Reports Server (NTRS)

    Chisnell, J. R.

    1984-01-01

    Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

  8. Genome-wide screen for inositol auxotrophy in Saccharomyces cerevisiae implicates lipid metabolism in stress response signaling

    PubMed Central

    Villa-García, Manuel J.; Choi, Myung Sun; Hinz, Flora I.; Gaspar, María L.; Jesch, Stephen A.

    2011-01-01

    Inositol auxotrophy (Ino− phenotype) in budding yeast has classically been associated with misregulation of INO1 and other genes involved in lipid metabolism. To identify all non-essential yeast genes that are necessary for growth in the absence of inositol, we carried out a genome-wide phenotypic screening for deletion mutants exhibiting Ino− phenotypes under one or more growth conditions. We report the identification of 419 genes, including 385 genes not previously reported, which exhibit this phenotype when deleted. The identified genes are involved in a wide range of cellular processes, but are particularly enriched in those affecting transcription, protein modification, membrane trafficking, diverse stress responses, and lipid metabolism. Among the Ino− mutants involved in stress response, many exhibited phenotypes that are strengthened at elevated temperature and/or when choline is present in the medium. The role of inositol in regulation of lipid metabolism and stress response signaling is discussed. PMID:21136082

  9. Constraints on just enough inflation preceded by a thermal era

    NASA Astrophysics Data System (ADS)

    Das, Suratna; Goswami, Gaurav; Prasad, Jayanti; Rangarajan, Raghavan

    2016-01-01

    If the inflationary era is preceded by a radiation-dominated era in which the inflaton too was in thermal equilibrium at some very early time, then the CMB data places an upper bound on the comoving temperature of the (decoupled) inflaton quanta. In addition, if one considers models of "just enough" inflation, where the number of e-foldings of inflation is just enough to solve the horizon and flatness problems, then we get a lower bound on the Hubble parameter during inflation, Hinf, which is in severe conflict with the upper bound from tensor perturbations. Alternatively, imposing the upper bound on Hinf implies that such scenarios are compatible with the data only if the number of relativistic degrees of freedom in the thermal bath in the preinflationary Universe is extremely large (greater than 109 or 1011 ). We are not aware of scenarios in which this can be satisfied.

  10. The physics of charge separation preceding lightning strokes in thunderclouds

    NASA Technical Reports Server (NTRS)

    Kyrala, Ali

    1987-01-01

    The physics of charge separation preceding lightning strokes in thunderclouds is presented by three types of arguments: An explanation is given for the aggregation of electrical charges of like sign overcoming Coulomb repulsion by attraction due to exchange interaction. The latter is well known in quantum mechanics from the theories of the nuclear bond and the covalent bond. A classical electrostatic model of charge balls of segregated positive and negative charges in the thundercloud is presented. These charge balls can only be maintained in temporarily stable locations by a containing vortex. Because they will be of different sizes and masses, they will stabilize at different altitudes when drag forces are included with the given electrostatic force. The question of how the charges become concentrated again after lightning discharges is approached by means of the collisional Boltzmann transport equation to explain quasi-periodic recharging. It is shown that solutions cannot be separable in both position and time if they are to represent aggregation.

  11. [The influences of laterality on global precedence: interference effects].

    PubMed

    Kimura, Jun

    2008-02-01

    This study aimed to clarify the influence of laterality on interference effects for global precedence, and to examine the mechanism of these effects. In most previous studies, the neutral condition was excluded from the consistency factor and the difference of latencies between the consistent and inconsistent conditions was regarded as the interference score, which may not be accurate. In this study, the difference of latencies between the neutral and the inconsistent condition was regarded as the interference score. The results of the analysis of variance (ANOVA) for latencies showed that interference effects influenced only right visual field-left hemisphere (RVF-LH), and facilitation effects influenced only left visual field-right hemisphere (LVF-RH) in the local condition. These findings indicate that it does not matter how optimal processing influenced interference effects on suboptimal processing in each hemisphere, for example how global processing influenced local processing in the right hemisphere, but rather how each hemisphere controlled optimal processing. PMID:18402064

  12. Heart rate dynamics preceding hemorrhage in the intensive care unit.

    PubMed

    Moss, Travis J; Clark, Matthew T; Lake, Douglas E; Moorman, J Randall; Calland, J Forrest

    2015-01-01

    Occult hemorrhage in surgical/trauma intensive care unit (STICU) patients is common and may lead to circulatory collapse. Continuous electrocardiography (ECG) monitoring may allow for early identification and treatment, and could improve outcomes. We studied 4,259 consecutive admissions to the STICU at the University of Virginia Health System. We collected ECG waveform data captured by bedside monitors and calculated linear and non-linear measures of the RR interbeat intervals. We tested the hypothesis that a transfusion requirement of 3 or more PRBC transfusions in a 24 hour period is preceded by dynamical changes in these heart rate measures and performed logistic regression modeling. We identified 308 hemorrhage events. A multivariate model including heart rate, standard deviation of the RR intervals, detrended fluctuation analysis, and local dynamics density had a C-statistic of 0.62. Earlier detection of hemorrhage might improve outcomes by allowing earlier resuscitation in STICU patients. PMID:26342251

  13. Quantification of fatty acids as methyl esters and phospholipids in cheese samples after separation of triacylglycerides and phospholipids.

    PubMed

    Hauff, Simone; Vetter, Walter

    2009-03-23

    Determination of the individual fatty acid composition of neutral- and phospholipids as well as the phospholipid content of dairy food and other foodstuffs are important tasks in life sciences. For these purposes, a method was developed for the separation of lipids (standards of triolein and diacylphosphatidylcholines as well as three cheese samples) by solid-phase extraction using a self-packed column filled with partly deactivated silica. Non-halogenated solvents were used for the elution of the lipid classes. Cyclohexane/ethyl acetate (1:1, v/v) served for the elution of neutral lipids, while polar lipids were eluted with three solvents (ethyl acetate/methanol, methanol, and methanol/water) into one fraction. The separated lipid fractions were transesterified and the individual fatty acids were quantified by using gas chromatography coupled to electron ionization mass spectrometry (GC/EI-MS) in the selected ion monitoring (SIM) mode. The recovery rate for standard phosphatidylcholines was approximately 90% and cross-contamination from neutral lipids was negligible. The method was applied to cheese samples. Quantitative amounts of individual fatty acids in the phospholipid fraction were <0.002-0.29% of total lipids from camembert, <0.002-0.12% of total lipids from mozzarella, and <0.002-0.18% of total lipids in a goat cream cheese. Differences in the fatty acid pattern of neutral and polar lipids were detected. The quantity of the fatty acids determined in the phospholipid fraction was divided by the factor 0.7 in order to convert the fatty acid content into the phospholipid content of the cheese samples. This factor is based on the contribution of 16:0 to dipalmitoylphosphatidylcholine (DPPC). The resulting DPPC equivalents (DPPC(eq)) were found to be representative for the average contribution of fatty acids to all classes of phospholipids in dairy products. Using this approach, the phospholipid content of lipids from mozzarella, camembert, and goat cream

  14. Stepped-to-dart leaders preceding lightning return strokes

    NASA Astrophysics Data System (ADS)

    Stolzenburg, Maribeth; Marshall, Thomas C.; Karunarathne, Sumedhe; Karunarathna, Nadeeka; Warner, Tom A.; Orville, Richard E.

    2013-09-01

    time-correlated high-speed video and electric field change data, three cases are described in which dart leaders toward ground are immediately preceded by stepped leaders that find and use previously used channels. These "stepped-to-dart leaders" occur in three natural negative ground flashes. Prior to the stepped-to-dart connection, the leaders have characteristics of stepped leaders, including average two-dimensional speeds of 1.6-2.7 × 105 m s-1 (visible from 5.5, 3.4, and 0.9 km altitude). After the connection, they behave as dart (or dart-stepped) leaders, with larger amplitude E-change pulses and faster average speeds of 3.4-7.8 × 106 m s-1. Connection altitudes are 3.32, 1.57, and 0.75 km. Immediately after the connection, there is a brief lighting in a short part of the prior return stroke channel. Luminosity travels up the stepped leader path after the connection, while the dart leader proceeds toward ground. In two cases, all the strokes subsequent to the stepped-to-dart stroke follow the visible portion of its channel. The other case has two subsequent strokes which do not reuse any portion of the stepped-to-dart channel. For the other 12 strokes in these flashes, stepped leader average speeds range from 1.7 to 3.0 × 105 m s-1, and dart leader average speeds are 0.82 to 16.67 × 106 m s-1. Overall, the return stroke waveforms give reasonable indication of the type of leader that preceded the stroke. Stepped-to-dart leaders are apparently rare in optical data, occurring in about 1% of subsequent strokes and 2.5% of flashes.

  15. A cold-induced myo-inositol transporter-like gene confers tolerance to multiple abiotic stresses in transgenic tobacco plants.

    PubMed

    Sambe, Mame Abdou Nahr; He, Xueying; Tu, Qinghua; Guo, Zhenfei

    2015-03-01

    A full length cDNA encoding a myo-inositol transporter-like protein, named as MfINT-like, was cloned from Medicago sativa subsp. falcata (herein falcata), a species with greater cold tolerance than alfalfa (M. sativa subsp. sativa). MfINT-like is located on plasma membranes. MfINT-like transcript was induced 2-4 h after exogenous myo-inositol treatment, 24-96 h with cold, and 96 h by salinity. Given that myo-inositol accumulates higher in falcata after 24 h of cold treatment, myo-inositol is proposed to be involved in cold-induced expression of MfINT-like. Higher levels of myo-inositol was observed in leaves of transgenic tobacco plants overexpressing MfINT-like than the wild-type but not in the roots of plants grown on myo-inositol containing medium, suggesting that transgenic plants had higher myo-inositol transport activity than the wild-type. Transgenic plants survived better to freezing temperature, and had lower ion leakage and higher maximal photochemical efficiency of photosystem II (Fv /Fm ) after chilling treatment. In addition, greater plant fresh weight was observed in transgenic plants as compared with the wild-type when plants were grown under drought or salinity stress. The results suggest that MfINT-like mediated transport of myo-inositol is associated with plant tolerance to abiotic stresses. PMID:25131886

  16. Rv2131c gene product: An unconventional enzyme that is both inositol monophosphatase and fructose-1,6-bisphosphatase

    SciTech Connect

    Gu Xiaoling; Chen Mao; Shen Hongbo; Jiang Xin; Huang Yishu; Wang Honghai . E-mail: hhwang@fudan.edu.cn

    2006-01-20

    Inositol monophosphatase is an enzyme in the biosynthesis of myo-inostiol, a crucial substrate for the synthesis of phosphatidylinositol, which has been demonstrated to be an essential component of mycobacteria. In this study, the Rv2131c gene from Mycobacterium tuberculosis H37Rv was cloned into the pET28a vector and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) strain, allowing the expression of the enzyme in fusion with a histidine-rich peptide on the N-terminal. The fusion protein was purified from the soluble fraction of the lysed cells under native conditions by immobilized metal affinity chromatography (IMAC). The purified Rv2131c gene product showed inositol monophosphatase activity but with substrate specificity that was broader than those of several bacterial and eukaryotic inositol monophosphatases, and it also acted as fructose-1,6-bisphosphatase. The dimeric enzyme exhibited dual activities of IMPase and FBPase, with K {sub m} of 0.22 {+-} 0.03 mM for inositol-1-phosphate and K {sub m} of 0.45 {+-} 0.05 mM for fructose-1,6-bisphosphatase. To better understand the relationship between the function and structure of the Rv2131c enzyme, we constructed D40N, L71A, and D94N mutants and purified these corresponding proteins. Mutations of D40N and D94N caused the proteins to almost completely lose both the inositol monophosphatase and fructose-1,6-bisphosphatase activities. However, L71A mutant did not cause loss either of the activities, but the activity toward the inositol was 12-fold more resistant to inhibition by lithium (IC{sub 5} {approx} 60 mM). Based on the substrate specificity and presence of conserved sequence motifs of the M. tuberculosis Rv2131c, we proposed that the enzyme belonged to class IV fructose-1,6-bisphosphatase (FBPase IV)

  17. Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues

    PubMed Central

    Chrétien, Françoise; Chapleur, Yves

    2016-01-01

    Summary Efficient routes were developed for the diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. The key steps of the synthesis were the easy accessibility of different types of arms in term of configuration (myo and scyllo), the linking method and length, which could modulate the biological properties. These inositol derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments. PMID:26977196

  18. Data on the optimization of a GC-MS procedure for the determination of total plasma myo-inositol.

    PubMed

    Guo, Jin; Shi, Yingfei; Xu, Chengbao; Zhong, Rugang; Zhang, Feng; Niu, Bo; Wang, Jianhua; Zhang, Ting

    2016-09-01

    Myo-inositol (MI) is one of the stereoisomers of hexahydroxycyclohexane, which plays an important role in intracellular signal pathway. Derivatization is an indispensable step in both external and internal standard method during the chromatography-mass spectrometer (GC-MS) detection, as MI can't be ionized directly. It is valuable to optimize the derivative process and the detection volume for clinical detection. This article contains optimization data related to research publication "Quantification of plasma myo-inositol using gas chromatography-mass spectrometry" [1]. Here we introduce the data on the optimized derivatization volume, temperature, duration and the detection volume. PMID:27508261

  19. Inositol 1,3,4,5,6-Pentakisphosphate 2-Kinase from Maize: Molecular and Biochemical Characterization[OA

    PubMed Central

    Sun, Yuejin; Thompson, Mark; Lin, Gaofeng; Butler, Holly; Gao, Zhifang; Thornburgh, Scott; Yau, Kerrm; Smith, Doug A.; Shukla, Vipula K.

    2007-01-01

    Inositol 1,3,4,5,6-pentakisphosphate 2-kinase, an enzyme encoded by the gene IPK1, catalyzes the terminal step in the phytic acid biosynthetic pathway. We report here the isolation and characterization of IPK1 cDNA and genomic clones from maize (Zea mays). DNA Southern-blot analysis revealed that ZmIPK1 in the maize genome constitutes a small gene family with two members. Two nearly identical ZmIPK1 paralogs, designated as ZmIPK1A and ZmIPK1B, were identified. The transcripts of ZmIPK1A were detected in various maize tissues, including leaves, silks, immature ears, seeds at 12 d after pollination, midstage endosperm, and maturing embryos. However, the transcripts of ZmIPK1B were exclusively detected in roots. A variety of alternative splicing products of ZmIPK1A were discovered in maize leaves and seeds. These products are derived from alternative acceptor sites, alternative donor sites, and retained introns in the transcripts. Consequently, up to 50% of the ZmIPK1A transcripts in maize seeds and leaves have an interrupted open reading frame. In contrast, only one type of splicing product of ZmIPK1B was detected in roots. When expressed in Escherichia coli and subsequently purified, the ZmIPK1 enzyme catalyzes the conversion of myo-inositol 1,3,4,5,6-pentakisphosphate to phytic acid. In addition, it is also capable of catalyzing the phosphorylation of myo-inositol 1,4,6-trisphosphate, myo-inositol 1,4,5,6-tetrakisphosphate, and myo-inositol 3,4,5,6-tetrakisphosphate. Nuclear magnetic resonance spectroscopy analysis indicates that the phosphorylation product of myo-inositol 1,4,6-trisphosphate is inositol 1,2,4,6-tetrakisphosphate. Kinetic studies showed that the Km for ZmIPK1 using myo-inositol 1,3,4,5,6-pentakisphosphate as a substrate is 119 μm with a Vmax at 625 nmol/min/mg. These data describing the tissue-specific accumulation and alternative splicing of the transcripts from two nearly identical ZmIPK1 paralogs suggest that maize has a highly sophisticated

  20. Phospholipid decoration of microcapsules containing perfluorooctyl bromide used as ultrasound contrast agents.

    PubMed

    Díaz-López, Raquel; Tsapis, Nicolas; Libong, Danielle; Chaminade, Pierre; Connan, Carole; Chehimi, Mohamed M; Berti, Romain; Taulier, Nicolas; Urbach, Wladimir; Nicolas, Valérie; Fattal, Elias

    2009-03-01

    We present here an easy method to modify the surface chemistry of polymeric microcapsules of perfluorooctyl bromide used as ultrasound contrast agents (UCAs). Capsules were obtained by a solvent emulsification-evaporation process with phospholipids incorporated in the organic phase before emulsification. Several phospholipids were reviewed: fluorescent, pegylated and biotinylated phospholipids. The influence of phospholipid concentration on microcapsule size and morphology was evaluated. Only a fraction of the phospholipids is associated to microcapsules, the rest being dissolved with the surfactant in the aqueous phase. Microscopy shows that phospholipids are present within the shell and that the core/shell structure is preserved up to 0.5 mg fluorescent phospholipids, up to about 0.25 mg pegylated phospholipids or biotinylated phospholipids (for 100 mg of polymer, poly(lactide-co-glycolide) (PLGA)). HPLC allows quantifying phospholipids associated to capsules: they correspond to 10% of pegylated phospholipids introduced in the organic phase. The presence of pegylated lipids at the surface of capsules was confirmed by X-ray photon electron spectroscopy (XPS). The pegylation did not modify the echographic signal arising from capsules. Finally biotinylated microcapsules incubated with neutravidin tend to aggregate, which confirms the presence of biotin at the surface. These results are encouraging and future work will consist of nanocapsule surface modification for molecular imaging. PMID:19097640

  1. Analysis of follicular fluid total phospholipids in women undergoing in-vitro fertilisation.

    PubMed

    Fayezi, S; Darabi, M; Darabi, M; Nouri, M; Rahimipour, A; Mehdizadeh, A

    2014-04-01

    Follicular fluid (FF) samples were obtained from 100 patients referred to the University Hospital. A total of 79 subjects underwent IVF and the remaining 21 underwent ICSI. The levels of apoA-I and total phospholipid were measured using turbidometric and colorimetric phosphorus assays, respectively. Correlation analysis showed a significant inverse association of total phospholipid in FF with fertilisation ratio (r = -0.24, p = 0.04). Furthermore, the ratio of phospholipid/apoA-I in patients with a percentage of fertilised oocytes ≤ 50% was significantly higher (> 2.5%, p < 0.05) than in those with higher percentages of fertilised oocytes. The amounts of phospholipid and phospholipid/apoA-I ratio in FF were associated negatively to the percentage of oocyte fertilisation. Therefore, the change in the phospholipid and phospholipid/apoA-I ratio of FF might be regarded as indicators of female fertility. PMID:24476398

  2. Inositol hexakisphosphate kinase-1 interacts with perilipin1 to modulate lipolysis.

    PubMed

    Ghoshal, Sarbani; Tyagi, Richa; Zhu, Qingzhang; Chakraborty, Anutosh

    2016-09-01

    Lipolysis leads to the breakdown of stored triglycerides (TAG) to release free fatty acids (FFA) and glycerol which is utilized by energy expenditure pathways to generate energy. Therefore, a decrease in lipolysis augments fat accumulation in adipocytes which promotes weight gain. Conversely, if lipolysis is not complemented by energy expenditure, it leads to FFA induced insulin resistance and type-2 diabetes. Thus, lipolysis is under stringent physiological regulation, although the precise mechanism of the regulation is not known. Deletion of inositol hexakisphosphate kinase-1 (IP6K1), the major inositol pyrophosphate biosynthetic enzyme, protects mice from high fat diet (HFD) induced obesity and insulin resistance. IP6K1-KO mice are lean due to enhanced energy expenditure. Therefore, IP6K1 is a target in obesity and type-2 diabetes. However, the mechanism/s by which IP6K1 regulates adipose tissue lipid metabolism is yet to be understood. Here, we demonstrate that IP6K1-KO mice display enhanced basal lipolysis. IP6K1 modulates lipolysis via its interaction with the lipolytic regulator protein perilipin1 (PLIN1). Furthermore, phosphorylation of IP6K1 at a PKC/PKA motif modulates its interaction with PLIN1 and lipolysis. Thus, IP6K1 is a novel regulator of PLIN1 mediated lipolysis. PMID:27373682

  3. Inositol phosphate kinase 2 is required for imaginal disc development in Drosophila

    PubMed Central

    Seeds, Andrew M.; Tsui, Marco M.; Sunu, Christine; Spana, Eric P.; York, John D.

    2015-01-01

    Inositol phosphate kinase 2 (Ipk2), also known as IP multikinase IPMK, is an evolutionarily conserved protein that initiates production of inositol phosphate intracellular messengers (IPs), which are critical for regulating nuclear and cytoplasmic processes. Here we report that Ipk2 kinase activity is required for the development of the adult fruit fly epidermis. Ipk2 mutants show impaired development of their imaginal discs, the primordial tissues that form the adult epidermis. Although disk tissue seems to specify normally during early embryogenesis, loss of Ipk2 activity results in increased apoptosis and impairment of proliferation during larval and pupal development. The proliferation defect is in part attributed to a reduction in JAK/STAT signaling, possibly by controlling production or secretion of the pathway’s activating ligand, Unpaired. Constitutive activation of the JAK/STAT pathway downstream of Unpaired partially rescues the disk growth defects in Ipk2 mutants. Thus, IP production is essential for proliferation of the imaginal discs, in part, by regulating JAK/STAT signaling. Our work demonstrates an essential role for Ipk2 in producing inositide messengers required for imaginal disk tissue maturation and subsequent formation of adult body structures and provides molecular insights to signaling pathways involved in tissue growth and stability during development. PMID:26647185

  4. The role of the inositol phosphate cascade in visual excitation of invertebrate microvillar photoreceptors

    PubMed Central

    1991-01-01

    The identity of the transmitter(s) involved in visual transduction in invertebrate microvillar photoreceptors remains unresolved. In this study, the role of inositol 1,4,5-trisphosphate (IP3) was examined in Limulus ventral photoreceptors by studying the effects on the light response of heparin and neomycin, agents that inhibit the production or action of IP3. Both heparin and neomycin reduce responses to brief flashes of light and the transient component of responses to steps of light, and also inhibit IP3-induced calcium release, indicating that IP3 plays a direct role in invertebrate visual excitation. The effects of BAPTA, a calcium buffer, were also examined and shown to be consistent with a role for IP3-mediated calcium release in visual excitation. However, all three agents fail to block the plateau component of the response to a step of light, indicating that a single pathway involving IP3 and calcium cannot solely be responsible for visual excitation in invertebrates. We suggest that the inositol phosphate cascade and a second parallel process that is not dependent on IP3 are involved in the production of the light response. PMID:1905344

  5. Sac2/INPP5F is an inositol 4-phosphatase that functions in the endocytic pathway

    PubMed Central

    Nakatsu, Fubito; Messa, Mirko; Nández, Ramiro; Czapla, Heather; Zou, Yixiao; Strittmatter, Stephen M.

    2015-01-01

    The recruitment of inositol phosphatases to endocytic membranes mediates dephosphorylation of PI(4,5)P2, a phosphoinositide concentrated in the plasma membrane, and prevents its accumulation on endosomes. The importance of the conversion of PI(4,5)P2 to PtdIns during endocytosis is demonstrated by the presence of both a 5-phosphatase and a 4-phosphatase (Sac domain) module in the synaptojanins, endocytic PI(4,5)P2 phosphatases conserved from yeast to humans and the only PI(4,5)P2 phosphatases in yeast. OCRL, another 5-phosphatase that couples endocytosis to PI(4,5)P2 dephosphorylation, lacks a Sac domain. Here we show that Sac2/INPP5F is a PI4P phosphatase that colocalizes with OCRL on endocytic membranes, including vesicles formed by clathrin-mediated endocytosis, macropinosomes, and Rab5 endosomes. An OCRL–Sac2/INPP5F interaction could be demonstrated by coimmunoprecipitation and was potentiated by Rab5, whose activity is required to recruit Sac2/INPP5F to endosomes. Sac2/INPP5F and OCRL may cooperate in the sequential dephosphorylation of PI(4,5)P2 at the 5 and 4 position of inositol in a partnership that mimics that of the two phosphatase modules of synaptojanin. PMID:25869668

  6. Inositol phosphate kinase 2 is required for imaginal disc development in Drosophila.

    PubMed

    Seeds, Andrew M; Tsui, Marco M; Sunu, Christine; Spana, Eric P; York, John D

    2015-12-22

    Inositol phosphate kinase 2 (Ipk2), also known as IP multikinase IPMK, is an evolutionarily conserved protein that initiates production of inositol phosphate intracellular messengers (IPs), which are critical for regulating nuclear and cytoplasmic processes. Here we report that Ipk2 kinase activity is required for the development of the adult fruit fly epidermis. Ipk2 mutants show impaired development of their imaginal discs, the primordial tissues that form the adult epidermis. Although disk tissue seems to specify normally during early embryogenesis, loss of Ipk2 activity results in increased apoptosis and impairment of proliferation during larval and pupal development. The proliferation defect is in part attributed to a reduction in JAK/STAT signaling, possibly by controlling production or secretion of the pathway's activating ligand, Unpaired. Constitutive activation of the JAK/STAT pathway downstream of Unpaired partially rescues the disk growth defects in Ipk2 mutants. Thus, IP production is essential for proliferation of the imaginal discs, in part, by regulating JAK/STAT signaling. Our work demonstrates an essential role for Ipk2 in producing inositide messengers required for imaginal disk tissue maturation and subsequent formation of adult body structures and provides molecular insights to signaling pathways involved in tissue growth and stability during development. PMID:26647185

  7. Kinetic crystallization separation process of the inositol isomers by controlling metastable zones

    NASA Astrophysics Data System (ADS)

    Konuki, Kaname; Hirasawa, Izumi

    2013-06-01

    D-chiro-inositol (DCI) is prepared by the immobilized enzyme reaction which uses myo-inositol (MI) as the substrate and the conversion rate is about 13%. The aim of this study was to develop a separation method for high purity DCI crystals from a reaction solution including low purity DCI only by the crystallization process. We succeeded in separating DCI crystals of 96% purity by water cooling crystallization, but it was presumed that scale-up was difficult. Although we tried anti-solvent crystallization similar to water cooling crystallization, high purity DCI crystals were not obtained. Therefore, we proposed the crystallization separation process by controlling metastable zones. The purity of a desired compound is controlled by this process, because solid-liquid separation is achieved before crystallization of compound in metastable zone. By the crystallization using this method, the DCI crystals of 97% purity were obtained. Although the yield per batch is about 50%, the actual yield is improved as the last mother liquor returns into the process of the following batch. When this process was repeated, the purity and the yield of DCI were reproduced and the robustness of this process was proved. It is expected that scale-up of this process will be successful, and this purification method could be applicable to similar systems such as separation of isomers and analogs.

  8. Brevis plant1, a putative inositol polyphosphate 5-phosphatase, is required for internode elongation in maize.

    PubMed

    Avila, Luis M; Cerrudo, Diego; Swanton, Clarence; Lukens, Lewis

    2016-03-01

    In maize (Zea mays L.), as in other grass species, stem elongation occurs during growth and most noticeably upon the transition to flowering. Genes that reduce stem elongation have been important to reduce stem breakage, or lodging. Stem elongation has been mediated by dwarf and brachytic/brevis plant mutants that affect giberellic acid and auxin pathways, respectively. Maize brevis plant1 (bv1) mutants, first identified over 80 years ago, strongly resemble brachytic2 mutants that have shortened internodes, short internode cells, and are deficient in auxin transport. Here, we characterized two novel bv1 maize mutants. We found that an inositol polyphosphate 5-phosphatase orthologue of the rice gene dwarf50 was the molecular basis for the bv1 phenotype, implicating auxin-mediated inositol polyphosphate and/or phosphoinositide signalling in stem elongation. We suggest that auxin-mediated internode elongation involves processes that also contribute to stem gravitropism. Genes misregulated in bv1 mutants included genes important for cell wall synthesis, transmembrane transport, and cytoskeletal function. Mutant and wild-type plants were indistinguishable early in development, responded similarly to changes in light quality, had unaltered flowering times, and had normal flower development. These attributes suggest that breeding could utilize bv1 alleles to increase crop grain yields. PMID:26767748

  9. Microtubule-Mediated Inositol Lipid Signaling Plays Critical Roles in Regulation of Blebbing

    PubMed Central

    Sugiyama, Tatsuroh; Pramanik, Md. Kamruzzaman; Yumura, Shigehiko

    2015-01-01

    Cells migrate by extending pseudopods such as lamellipodia and blebs. Although the signals leading to lamellipodia extension have been extensively investigated, those for bleb extension remain unclear. Here, we investigated signals for blebbing in Dictyostelium cells using a newly developed assay to induce blebbing. When cells were cut into two pieces with a microneedle, the anucleate fragments vigorously extended blebs. This assay enabled us to induce blebbing reproducibly, and analyses of knockout mutants and specific inhibitors identified candidate molecules that regulate blebbing. Blebs were also induced in anucleate fragments of leukocytes, indicating that this assay is generally applicable to animal cells. After cutting, microtubules in the anucleate fragments promptly depolymerized, followed by the extension of blebs. Furthermore, when intact cells were treated with a microtubule inhibitor, they frequently extended blebs. The depolymerization of microtubules induced the delocalization of inositol lipid phosphatidylinositol 3,4,5-trisphosphate from the cell membrane. PI3 kinase-null cells frequently extended blebs, whereas PTEN-null cells extended fewer blebs. From these observations, we propose a model in which microtubules play a critical role in bleb regulation via inositol lipid metabolism. PMID:26317626

  10. Chemogenetic Characterization of Inositol Phosphate Metabolic Pathway Reveals Druggable Enzymes for Targeting Kinetoplastid Parasites.

    PubMed

    Cestari, Igor; Haas, Paige; Moretti, Nilmar Silvio; Schenkman, Sergio; Stuart, Ken

    2016-05-19

    Kinetoplastids cause Chagas disease, human African trypanosomiasis, and leishmaniases. Current treatments for these diseases are toxic and inefficient, and our limited knowledge of drug targets and inhibitors has dramatically hindered the development of new drugs. Here we used a chemogenetic approach to identify new kinetoplastid drug targets and inhibitors. We conditionally knocked down Trypanosoma brucei inositol phosphate (IP) pathway genes and showed that almost every pathway step is essential for parasite growth and infection. Using a genetic and chemical screen, we identified inhibitors that target IP pathway enzymes and are selective against T. brucei. Two series of these inhibitors acted on T. brucei inositol polyphosphate multikinase (IPMK) preventing Ins(1,4,5)P3 and Ins(1,3,4,5)P4 phosphorylation. We show that IPMK is functionally conserved among kinetoplastids and that its inhibition is also lethal for Trypanosoma cruzi. Hence, IP enzymes are viable drug targets in kinetoplastids, and IPMK inhibitors may aid the development of new drugs. PMID:27133314

  11. Potentiometric and spectroscopic study of the interaction of 3d transition metal ions with inositol hexakisphosphate

    NASA Astrophysics Data System (ADS)

    Veiga, Nicolás; Macho, Israel; Gómez, Kerman; González, Gabriel; Kremer, Carlos; Torres, Julia

    2015-10-01

    Among myo-inositol phosphates, the most abundant in nature is the myo-inositol hexakisphosphate, InsP6. Although it is known to be vital to cell functioning, the biochemical research into its metabolism needs chemical and structural analysis of all the protonation, complexation and precipitation processes that it undergoes in the biological media. In view of its high negative charge at physiological level, our group has been leading a thorough research into the InsP6 chemical and structural behavior in the presence of the alkali and alkaline earth metal ions essential for life. The aim of this article is to extend these studies, dealing with the chemical and structural features of the InsP6 interaction with biologically relevant 3d transition metal ions (Fe(II), Fe(III), Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)), in a non-interacting medium and under simulated physiological conditions. The metal-complex stability constants were determined by potentiometry, showing under ligand-excess conditions the formation of mononuclear species in different protonation states. Under metal ion excess, polymetallic species were detected for Fe(II), Fe(III), Zn(II) and Cu(II). Additionally, the 31P NMR and UV-vis spectroscopic studies provided interesting structural aspects of the strong metal ion-InsP6 interaction.

  12. CHARMM Additive All-Atom Force Field for Acyclic Polyalcohols, Acyclic Carbohydrates and Inositol

    PubMed Central

    Hatcher, Elizabeth; Guvench, Olgun; MacKerell, Alexander D.

    2009-01-01

    Parametrization of the additive all-atom CHARMM force field for acyclic polyalcohols, acyclic carbohydrates and inositol is conducted. Initial parameters were transferred from the alkanes and hexopyranose carbohydrates, with subsequent development and optimization of parameters unique to the molecules considered in this study. Using the model compounds acetone and acetaldehyde, nonbonded parameters for carbonyls were optimized targeting quantum mechanical interaction data for solute-water pairs and pure solvent thermodynamic data. Bond and angle parameters were adjusted by comparing optimized geometries to small molecule crystal survey data and by performing vibrational analyses on acetone, acetaldehyde and glycerol. C-C-C-C, C-C-C-O, C-C-OH and O-C-C-O torsional parameters for polyol chains were fit to quantum mechanical dihedral potential energy scans comprising over 1500 RIMP2/cc-pVTZ//MP2/6-31G(d) conformations using an automated Monte Carlo simulated annealing procedure. Comparison of computed condensed-phase data, including crystal lattice parameters and densities, NMR proton-proton couplings, densities and diffusion coefficients of aqueous solutions, to experimental data validated the optimized parameters. Parameter development for these compounds proved particularly challenging because of the flexibility of the acyclic sugars and polyalcohols as well as the intramolecular hydrogen bonding between vicinal hydroxyls for all of the compounds. The newly optimized additive CHARMM force field parameters are anticipated to be of utility for atomic level of detail simulations of acyclic polyalcohols, acyclic carbohydrates and inositol in solution. PMID:20160980

  13. INOSITOL HEXAKISPHOSPHATE MEDIATES APOPTOSIS IN HUMAN BREAST ADENOCARCINOMA MCF-7 CELL LINE VIA INTRINSIC PATHWAY

    SciTech Connect

    Agarwal, Rakhee; Ali, Nawab

    2010-04-12

    Inositol polyphosphates (InsP{sub s}) are naturally occurring compounds ubiquitously present in plants and animals. Inositol hexakisphosphate (InsP{sub 6}) is the most abundant among all InsP{sub s} and constitutes the major portion of dietary fiber in most cereals, legumes and nuts. Certain derivatives of InsP{sub s} also regulate cellular signaling mechanisms. InsP{sub s} have also been shown to reduce tumor formation and induce apoptosis in cancerous cells. Therefore, in this study, the effects of InsPs on apoptosis were studied in an attempt to investigate their potential anti-cancer therapeutic application and understand their mechanism of action. Acridine orange and ethidium bromide staining suggested that InsP{sub 6} dose dependently induced apoptosis in human breast adenocarcinoma MCF-7 cells. Among InsP{sub s} tested (InsP{sub 3}, InsP{sub 4}, InsP{sub 5}, and InsP{sub 6}), InsP{sub 6} was found to be the most effective in inducing apoptosis. Furthermore, effects of InsP{sub 6} were found most potent inducing apoptosis. Etoposide, the drug known to induce apoptosis in both in vivo and in vitro, was used as a positive control. Western blotting experiments using specific antibodies against known apoptotic markers suggested that InsP{sub 6} induced apoptotic changes were mediated via an intrinsic apoptotic pathway.

  14. Inositol Hexakisphosphate Mediates Apoptosis in Human Breast Adenocarcinoma MCF-7 Cell Line via Intrinsic Pathway

    NASA Astrophysics Data System (ADS)

    Agarwal, Rakhee; Ali, Nawab

    2010-04-01

    Inositol polyphosphates (InsPs) are naturally occurring compounds ubiquitously present in plants and animals. Inositol hexakisphosphate (InsP6) is the most abundant among all InsPs and constitutes the major portion of dietary fiber in most cereals, legumes and nuts. Certain derivatives of InsPs also regulate cellular signaling mechanisms. InsPs have also been shown to reduce tumor formation and induce apoptosis in cancerous cells. Therefore, in this study, the effects of InsPs on apoptosis were studied in an attempt to investigate their potential anti-cancer therapeutic application and understand their mechanism of action. Acridine orange and ethidium bromide staining suggested that InsP6 dose dependently induced apoptosis in human breast adenocarcinoma MCF-7 cells. Among InsPs tested (InsP3, InsP4, InsP5, and InsP6), InsP6 was found to be the most effective in inducing apoptosis. Furthermore, effects of InsP6 were found most potent inducing apoptosis. Etoposide, the drug known to induce apoptosis in both in vivo and in vitro, was used as a positive control. Western blotting experiments using specific antibodies against known apoptotic markers suggested that InsP6 induced apoptotic changes were mediated via an intrinsic apoptotic pathway.

  15. Brevis plant1, a putative inositol polyphosphate 5-phosphatase, is required for internode elongation in maize

    PubMed Central

    Avila, Luis M.; Cerrudo, Diego; Swanton, Clarence

    2016-01-01

    In maize (Zea mays L.), as in other grass species, stem elongation occurs during growth and most noticeably upon the transition to flowering. Genes that reduce stem elongation have been important to reduce stem breakage, or lodging. Stem elongation has been mediated by dwarf and brachytic/brevis plant mutants that affect giberellic acid and auxin pathways, respectively. Maize brevis plant1 (bv1) mutants, first identified over 80 years ago, strongly resemble brachytic2 mutants that have shortened internodes, short internode cells, and are deficient in auxin transport. Here, we characterized two novel bv1 maize mutants. We found that an inositol polyphosphate 5-phosphatase orthologue of the rice gene dwarf50 was the molecular basis for the bv1 phenotype, implicating auxin-mediated inositol polyphosphate and/or phosphoinositide signalling in stem elongation. We suggest that auxin-mediated internode elongation involves processes that also contribute to stem gravitropism. Genes misregulated in bv1 mutants included genes important for cell wall synthesis, transmembrane transport, and cytoskeletal function. Mutant and wild-type plants were indistinguishable early in development, responded similarly to changes in light quality, had unaltered flowering times, and had normal flower development. These attributes suggest that breeding could utilize bv1 alleles to increase crop grain yields. PMID:26767748

  16. Myo-Inositol in the Treatment of Teenagers Affected by PCOS

    PubMed Central

    Barbakadze, Ludmila; Kvashilava, Nana

    2016-01-01

    Objective. To compare the effectiveness of myo-inositol (MI) and oral contraceptive pills (OCPs) in monotherapy and MI in combination with OCPs in the treatment of teenagers affected by polycystic ovary syndrome (PCOS). Methods. 61 adolescent girls aged 13–19 years, with PCOS, were involved in the prospective, open-label study. Patients were randomized into three groups: I group, 20 patients receiving drospirenone 3 mg/ethinyl estradiol 30 μg; II group, 20 patients receiving 4 g myo-inositol plus 400 mg folic acid; III group, 21 patients receiving both medications. Results. After receiving MI significant reduction in weight, BMI, glucose, C-peptide, insulin, HOMA-IR, FT, and LH was detected. The levels of SHBG, TT, FAI, DHEA-S, and AMH did not change statistically significantly. After receiving OCPs weight and BMI slightly increased, but metabolic parameters did not change. Combination of MI and OCPs did not change weight and BMI, but reduction in C-peptide, insulin, and HOMA-IR was detected. TT, FT, FAI, DHEA-S, LH, and AMH levels decreased and SHBG increased. Conclusions. Administration of MI is a safe and effective method to prevent and correct metabolic disorders in teenagers affected by PCOS. With combination of MI and OCPs antiandrogenic effects are enhanced, negative impact of OCPs on weight gain is balanced, and metabolic profile is improved.

  17. Migration of phospholipid vesicles in response to OH(-) stimuli.

    PubMed

    Kodama, Atsuji; Sakuma, Yuka; Imai, Masayuki; Oya, Yutaka; Kawakatsu, Toshihiro; Puff, Nicolas; Angelova, Miglena I

    2016-03-21

    We demonstrate migration of phospholipid vesicles in response to a pH gradient. Upon simple micro-injection of a NaOH solution, the vesicles linearly moved to the tip of the micro-pipette and the migration velocity was proportional to the gradient of OH(-) concentration. Vesicle migration was characteristic of OH(-) ions and no migration was observed for monovalent salts or nonionic sucrose solutions. The migration of vesicles is quantitatively described by the surface tension gradient model where the hydrolysis of the phospholipids by NaOH solution decreases the surface tension of the vesicle. The vesicles move toward a direction where the surface energy decreases. Thus the chemical modification of lipids produces a mechanical force to drive vesicles. PMID:26883729

  18. Hormetic and anti-inflammatory properties of oxidized phospholipids.

    PubMed

    Mauerhofer, Christina; Philippova, Maria; Oskolkova, Olga V; Bochkov, Valery N

    2016-06-01

    Oxidized phospholipids are generally recognized as deleterious factors involved in disease pathogenesis. This review summarizes the data suggesting that under certain biological conditions the opposite is correct, namely that OxPLs can also induce protective effects. Examples that are discussed in the review include upregulation of antioxidant genes, inhibition of inflammatory signaling pathways through Nrf2-dependent and -independent mechanisms, antagonism of Toll-like receptors, immuno-modulating and immuno-suppressive action of OxPLs in adaptive immunity and autoimmune disease, activation of PPARs known for their anti-inflammatory action, as well as protective action against lung edema in acute lung inflammation. The data support the notion that oxidation of phospholipids provides a negative feedback preventing damage to host tissues due to uncontrolled inflammation and oxidative stress. PMID:26948981

  19. Hyperbaric hyperoxia reversibly inhibits erythrocyte phospholipid fatty acid turnover

    NASA Technical Reports Server (NTRS)

    Dise, Craig A.; Clark, James M.; Lambersten, Christian J.; Goodman, David B. P.

    1987-01-01

    The effect of hyperbaric hyperoxia on the acylation of membrane phospholipid was studied by measuring the rates of activation of exogenous tritiated oleic acid to acyl thioester and of transesterification of the thioester into membrane phospholipids in intact human erythrocytes obtained 1 h after an exposure of the subjects to a hyperbaric oxygen atmosphere (3.5 h, 100 pct O2, 3 ATA). Exposure to pure oxygen was found to inhibit both the acylation and transesterification reactions by more than 30 percent, with partial recovery detected 24 h later. On the other hand, no rate changes were observed when isolated membranes from the same batches of cells were used in similar experiments. It is suggested that the decrease in the incorporation of tritiated oleic acid after hyperbaric hyperoxia may reflect an early event in the pathogenesis of oxygen-induced cellular injury and that it may be a useful index for the assessment of the tolerance of tissues to hyperoxia.

  20. A Cholesterol Recognition Motif in Human Phospholipid Scramblase 1

    PubMed Central

    Posada, Itziar M.D.; Fantini, Jacques; Contreras, F. Xabier; Barrantes, Francisco; Alonso, Alicia; Goñi, Félix M.

    2014-01-01

    Human phospholipid scramblase 1 (SCR) catalyzes phospholipid transmembrane (flip-flop) motion. This protein is assumed to bind the membrane hydrophobic core through a transmembrane domain (TMD) as well as via covalently bound palmitoyl residues. Here, we explore the possible interaction of the SCR TMD with cholesterol by using a variety of experimental and computational biophysical approaches. Our findings indicate that SCR contains an amino acid segment at the C-terminal region that shows a remarkable affinity for cholesterol, although it lacks the CRAC sequence. Other 3-OH sterols, but not steroids lacking the 3-OH group, also bind this region of the protein. The newly identified cholesterol-binding region is located partly at the C-terminal portion of the TMD and partly in the first amino acid residues in the SCR C-terminal extracellular coil. This finding could be related to the previously described affinity of SCR for cholesterol-rich domains in membranes. PMID:25229146

  1. Light and phospholipid driven structural transitions in nematic microdroplets

    SciTech Connect

    Dubtsov, A. V. Pasechnik, S. V.; Shmeliova, D. V.; Kralj, Samo

    2014-10-13

    We studied the UV-irradiation and phospholipid driven bipolar-radial structural transitions within azoxybenzene nematic liquid crystal (LC) droplets dispersed in water. It was found that the UV-irradiation induced trans-cis isomerisation of LC molecules could enable structural transitions into radial-type configurations at a critical UV-irradiation time t{sub c}. In particular, we show that under appropriate conditions, a value of t{sub c} could sensitively fingerprint the concentration of phospholipid molecules present in LC-water dispersions. This demonstrated proof-of-principle mechanism could be exploited for development of sensitive detectors for specific nanoparticles (NPs), where value of t{sub c} reveals concentration of NPs.

  2. The influence of plant hormones on phospholipid monolayer stability.

    PubMed

    Gzyl-Malchera, Barbara; Filek, Maria; Brezesinski, Gerald; Fischer, Antje

    2007-01-01

    The influence of hormones in water subphase on the stability of monolayers built of phospholipid mixtures extracted from embryogenic (PLE) and nonembryogenic (PLNE) wheat calli was examined. Additionally, experiments on individual lipids, dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidic acid (DPPA), were performed. DPPC was chosen because it was the main phospholipid present in both calli. Negatively charged DPPA could mimic a negatively charged natural mixture of lipids. As hormones, auxins (IAA and 2,4-D), cytokinins (zeatin and kinetin) and zearalenone were chosen. The time of monolayer stability for PLNE calli was much longer than for PLE calli. Kinetics of monolayer stability of PLNE was similar to DPPA, whereas that of PLE was similar to DPPC. Generally, hormones increased the time after which the monolayer stability was reached and decreased the surface pressure. The greatest effect was observed for auxins (especially IAA), whereas cytokinins affected the monolayer stability to a lesser degree. PMID:17425106

  3. Localization of Anionic Phospholipids in Escherichia coli Cells

    PubMed Central

    Oliver, Piercen M.; Crooks, John A.; Leidl, Mathias; Yoon, Earl J.; Saghatelian, Alan

    2014-01-01

    Cardiolipin (CL) is an anionic phospholipid with a characteristically large curvature and is of growing interest for two primary reasons: (i) it binds to and regulates many peripheral membrane proteins in bacteria and mitochondria, and (ii) it is distributed asymmetrically in rod-shaped cells and is concentrated at the poles and division septum. Despite the growing number of studies of CL, its function in bacteria remains unknown. 10-N-Nonyl acridine orange (NAO) is widely used to image CL in bacteria and mitochondria, as its interaction with CL is reported to produce a characteristic red-shifted fluorescence emission. Using a suite of biophysical techniques, we quantitatively studied the interaction of NAO with anionic phospholipids under physiologically relevant conditions. We found that NAO is promiscuous in its binding and has photophysical properties that are largely insensitive to the structure of diverse anionic phospholipids to which it binds. Being unable to rely solely on NAO to characterize the localization of CL in Escherichia coli cells, we instead used quantitative fluorescence microscopy, mass spectrometry, and mutants deficient in specific classes of anionic phospholipids. We found CL and phosphatidylglycerol (PG) concentrated in the polar regions of E. coli cell membranes; depletion of CL by genetic approaches increased the concentration of PG at the poles. Previous studies suggested that some CL-binding proteins also have a high affinity for PG and display a pattern of cellular localization that is not influenced by depletion of CL. Framed within the context of these previous experiments, our results suggest that PG may play an essential role in bacterial physiology by maintaining the anionic character of polar membranes. PMID:25002539

  4. Differential Intrahepatic Phospholipid Zonation in Simple Steatosis and Nonalcoholic Steatohepatitis

    PubMed Central

    Wattacheril, Julia; Seeley, Erin H.; Angel, Peggi; Chen, Heidi; Bowen, Benjamin P.; Lanciault, Christian; M.Caprioli, Richard; Abumrad, Naji; Flynn, Charles Robb

    2013-01-01

    Nonalcoholic fatty liver disease (NAFLD) occurs frequently in a setting of obesity, dyslipidemia and insulin resistance, but the etiology of the disease, particularly the events favoring progression to nonalcoholic steatohepatitis (NASH) as opposed to simple steatosis (SS), are not fully understood. Based on known zonation patterns in protein, glucose and lipid metabolism, coupled with evidence that phosphatidylcholine may play a role in NASH pathogenesis, we hypothesized that phospholipid zonation exists in liver and that specific phospholipid abundance and distribution may be associated with histologic disease. A survey of normal hepatic protein expression profiles in the Human Protein Atlas revealed pronounced zonation of enzymes involved in lipid utilization and storage, particularly those facilitating phosphatidylcholine (PC) metabolism. Immunohistochemistry of obese normal, SS and NASH liver specimens with anti-phosphatidylethanomine N-methyltransferase (PEMT) antibodies showed a progressive decrease in the zonal distribution of this PC biosynthetic enzyme. Phospholipid quantitation by liquid chromatography mass spectrometry (LC-MS) in hepatic extracts of Class III obese patients with increasing NAFLD severity revealed that most PC species with 32, 34 and 36 carbons as well as total PC abundance was decreased with SS and NASH. Matrix assisted laser desorption ionization - imaging mass spectrometry (MALDI-IMS) imaging revealed strong zonal distributions for 32, 34 and 36 carbon PCs in controls (minimal histologic findings) and SS that was lost in NASH specimens. Specific lipid species such as PC 34∶1 and PC 36∶2 best illustrated this phenomenon. These findings suggest that phospholipid zonation may be associated with the presence of an intrahepatic proinflammatory phenotype and thus have broad implications in the etiopathogenesis of NASH. PMID:23451176

  5. Inhibition of phospholipid methylation by a cytosolic factor.

    PubMed Central

    Alvarez Chiva, V; Mato, J M

    1984-01-01

    Rat liver cytosol contains a heat-stable factor which inhibits phospholipid methylation by rat liver microsomes. The effect of this factor on lipid methylation was dose- and pH-dependent. This factor has an Mr of approx. 3200 as estimated by gel filtration. It could not be extracted by chloroform/methanol (2:1, v/v), and its action was inhibited by incubation with subtilisin. PMID:6712636

  6. NMR Structures of Membrane Proteins in Phospholipid Bilayers

    PubMed Central

    Radoicic, Jasmina; Lu, George J.; Opella, Stanley J.

    2014-01-01

    Membrane proteins have always presented technical challenges for structural studies because of their requirement for a lipid environment. Multiple approaches exist including X-ray crystallography and electron microscopy that can give significant insights into their structure and function. However, nuclear magnetic resonance (NMR) is unique in that it offers the possibility of determining the structures of unmodified membrane proteins in their native environment of phospholipid bilayers under physiological conditions. Furthermore, NMR enables the characterization of the structure and dynamics of backbone and side chain sites of the proteins alone and in complexes with both small molecules and other biopolymers. The learning curve has been steep for the field as most initial studies were performed under non-native environments using modified proteins until ultimately progress in both techniques and instrumentation led to the possibility of examining unmodified membrane proteins in phospholipid bilayers under physiological conditions. This review aims to provide an overview of the development and application of NMR to membrane proteins. It highlights some of the most significant structural milestones that have been reached by NMR spectroscopy of membrane proteins; especially those accomplished with the proteins in phospholipid bilayer environments where they function. PMID:25032938

  7. Enteropathogenic Escherichia coli Infection Triggers Host Phospholipid Metabolism Perturbations

    PubMed Central

    Wu, Y.; Lau, B.; Smith, S.; Troyan, K.; Barnett Foster, D. E.

    2004-01-01

    Enteropathogenic Escherichia coli (EPEC) specifically recognizes phosphatidylethanolamine (PE) on the outer leaflet of host epithelial cells. EPEC also induces apoptosis in epithelial cells, which results in increased levels of outer leaflet PE and increased bacterial binding. Consequently, it is of interest to investigate whether EPEC infection perturbs host cell phospholipid metabolism and whether the changes play a role in the apoptotic signaling. Our findings indicate that EPEC infection results in a significant increase in the epithelial cell PE level and a corresponding decrease in the phosphatidylcholine (PC) level. PE synthesis via both the de novo pathway and the serine decarboxylation pathway was enhanced, and de novo synthesis of phosphatidylcholine via CDP-choline was reduced. The changes were transitory, and the maximum change was noted after 4 to 5 h of infection. Addition of exogenous PC or CDP-choline to epithelial cells prior to infection abrogated EPEC-induced apoptosis, suggesting that EPEC infection inhibits the CTP-phosphocholine cytidylyltransferase step in PC synthesis, which is reportedly inhibited during nonmicrobially induced apoptosis. On the other hand, incorporation of exogenous PE by the host cells enhanced EPEC-induced apoptosis and necrosis without increasing bacterial adhesion. This is the first report that pathogen-induced apoptosis is associated with significant changes in PE and PC metabolism, and the results suggest that EPEC adhesion to a host membrane phospholipid plays a role in disruption of host phospholipid metabolism. PMID:15557596

  8. Hydrophobic Silica Nanoparticles Induce Gel Phases in Phospholipid Monolayers.

    PubMed

    Orsi, Davide; Rimoldi, Tiziano; Guzmán, Eduardo; Liggieri, Libero; Ravera, Francesca; Ruta, Beatrice; Cristofolini, Luigi

    2016-05-17

    Silica nanoparticles (SiNP) can be incorporated in phospholipid layers to form hybrid organic-inorganic bidimensional mesostructures. Controlling the dynamics in these mesostructures paves the way to high-performance drug-delivery systems. Depending on the different hydrophobicity/hydrophilicity of SiNP, recent X-ray reflectivity experiments have demonstrated opposite structural effects. While these are reasonably well understood, less is known about the effects on the dynamics, which in turn determine molecular diffusivity and the possibility of drug release. In this work we characterize the dynamics of a mixed Langmuir layer made of phospholipid and hydrophobic SiNP. We combine X-ray photon correlation spectroscopy and epifluorescence discrete Fourier microscopy to cover more than 2 decades of Q-range (0.3-80 μm(-1)). We obtain evidence for the onset of an arrested state characterized by intermittent stress-relaxation rearrangement events, corresponding to a gel dominated by attractive interactions. We compare this with our previous results from phospholipid/hydrophilic SiNP films, which show an arrested glassy phase of repulsive disks. PMID:27133453

  9. Bile salt-phospholipid aggregation at submicellar concentrations.

    PubMed

    Baskin, Rebekah; Frost, Laura D

    2008-04-01

    The aggregation behavior of the bile salts taurodeoxycholate (NaTDC) and sodium cholate (NaC), are followed at concentrations below critical micelle concentrations (CMCs) using the environment sensitive, fluorescent-labeled phospholipid, 2-(6-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)hexanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine (NBD-C(6)-HPC). A buffer solution containing NBD-C(6)-HPC is titrated with increasing NaC or NaTDC and the fluorescence changes followed. Both bile salts induced fluorescence changes below their critical micelle concentration indicating the presence of a bile salt-phospholipid aggregate. A critical control experiment using 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino) hexanoic acid (NBD-X) shows that the bile salts are interacting with the longer, C16 hydrocarbon tail, not the NBD probe. The fluorescence curves were fitted to the Hill equation as a model for cooperative aggregation. The cooperativity model provides a minimum estimate for the number of bile salts to give maximal fluorescence. This number was calculated for NaC and NaTDC to have a minimum value of approximately 2. A small aggregation number supports the existence of primary micellar aggregates at submicellar concentrations for bile salt-phospholipid aqueous solutions. PMID:18035524

  10. THE CATION CONTENT OF PHOSPHOLIPIDES FROM SWINE ERYTHROCYTES

    PubMed Central

    Kirschner, Leonard B.

    1958-01-01

    Phospholipides from swine erythrocytes were isolated and separated into four reproducible fractions. One of the fractions seems to be pure phosphatidylserine. The others are almost certainly not single compounds, although the analytical data indicate that they represent mixtures considerably simpler than the parent mixture extracted from the cells. All four fractions contained Na+ and K+, but very little Ca2+. Sodium was the predominant cation in two of the fractions under all conditions although the major intracellular cation was potassium. In the other two fractions the ratio Na/K varied with the extraction procedure largely because the quantity of K+ seemed to depend on the solvent system used. There appear to be reasons to believe that the entire system of phospholipides binds Na+ preferentially. In addition, it was observed that the quantity of Na+ found in the lipide extracts varied when the extrusion of Na+ from the cells was made to vary. Both of these observations are consistent with the possibility that the phospholipides play some part in the extrusion of Na+ from these cells. PMID:13587908

  11. Peroxidase activation of cytoglobin by anionic phospholipids: Mechanisms and consequences.

    PubMed

    Tejero, Jesús; Kapralov, Alexandr A; Baumgartner, Matthew P; Sparacino-Watkins, Courtney E; Anthonymutu, Tamil S; Vlasova, Irina I; Camacho, Carlos J; Gladwin, Mark T; Bayir, Hülya; Kagan, Valerian E

    2016-05-01

    Cytoglobin (Cygb) is a hexa-coordinated hemoprotein with yet to be defined physiological functions. The iron coordination and spin state of the Cygb heme group are sensitive to oxidation of two cysteine residues (Cys38/Cys83) and/or the binding of free fatty acids. However, the roles of redox vs lipid regulators of Cygb's structural rearrangements in the context of the protein peroxidase competence are not known. Searching for physiologically relevant lipid regulators of Cygb, here we report that anionic phospholipids, particularly phosphatidylinositolphosphates, affect structural organization of the protein and modulate its iron state and peroxidase activity both conjointly and/or independently of cysteine oxidation. Thus, different anionic lipids can operate in cysteine-dependent and cysteine-independent ways as inducers of the peroxidase activity. We establish that Cygb's peroxidase activity can be utilized for the catalysis of peroxidation of anionic phospholipids (including phosphatidylinositolphosphates) yielding mono-oxygenated molecular species. Combined with the computational simulations we propose a bipartite lipid binding model that rationalizes the modes of interactions with phospholipids, the effects on structural re-arrangements and the peroxidase activity of the hemoprotein. PMID:26928591

  12. The innate immune response to products of phospholipid peroxidation.

    PubMed

    Weismann, David; Binder, Christoph J

    2012-10-01

    Lipid peroxidation occurs in the context of many physiological processes but is greatly increased in various pathological situations. A consequence of phospholipid peroxidation is the generation of oxidation-specific epitopes, such as phosphocholine of oxidized phospholipids and malondialdehyde, which form neo-self determinants on dying cells and oxidized low-density lipoproteins. In this review we discuss evidence demonstrating that pattern recognition receptors of the innate immune system recognize oxidation-specific epitopes as endogenous damage-associated molecular patterns, allowing the host to identify dangerous biological waste. Oxidation-specific epitopes are important targets of both cellular and soluble pattern recognition receptors, including toll-like and scavenger receptors, C-reactive protein, complement factor H, and innate natural IgM antibodies. This recognition allows the innate immune system to mediate important physiological house keeping functions, for example by promoting the removal of dying cells and oxidized molecules. Once this system is malfunctional or overwhelmed the development of diseases, such as atherosclerosis and age-related macular degeneration is favored. Understanding the molecular components and mechanisms involved in this process, will help the identification of individuals with increased risk of developing chronic inflammation, and indicate novel points for therapeutic intervention. This article is part of a Special Issue entitled: Oxidized phospholipids-their properties and interactions with proteins. PMID:22305963

  13. Ultraviolet radiation alters choline phospholipid metabolism in human keratinocytes

    SciTech Connect

    DeLeo, V.; Scheide, S.; Meshulam, J.; Hanson, D.; Cardullo, A.

    1988-10-01

    Ultraviolet radiation B (UVB-290-320 nm) induces inflammation and hyperproliferation in human epidermis. This response is associated with the recovery from irradiated skin of inflammatory mediators derived from membrane phospholipids. We have previously reported that UVB stimulates the production of such mediators by human keratinocytes (HK) in culture. In these studies we examined the effect of UVB on the metabolism of choline containing phospholipids in HK prelabeled with (/sup 3/H) choline. UVB (400-1600J/m2) stimulated a dose dependent release of (/sup 3/H) choline from HK within minutes of irradiation. Examination of media extracts by paper chromatography revealed that the released (/sup 3/H) choline was predominately in the form of glycerophosphorylcholine. Examination of label remaining in membranes of cells after irradiation by acid precipitation and HPLC revealed that the origin of the released (/sup 3/H) choline was the membrane phosphatidylcholine/lysophosphatidylcholine. These data support a concept of UVB stimulation of both a phospholipase A (1 or 2) and a lysophospholipase. These UVB induced alterations of HK membrane phospholipid metabolism likely have profound effects on UVB-induced inflammation and control of cell growth in human skin.

  14. Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery.

    PubMed

    Mendes, Ana C; Gorzelanny, Christian; Halter, Natalia; Schneider, Stefan W; Chronakis, Ioannis S

    2016-08-20

    Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248±94nm to 600±201nm, depending on the amount of phospholipids used. Fourier Transformed Infra-Red (FTIR) spectroscopy and Dynamic Light Scattering (DLS) data suggested the occurrence of electrostatic interactions between amine groups of chitosan with the phospholipid counterparts. The nanofibers were shown to be stable for at least 7days in Phosphate Buffer Saline (PBS) solution. Cytotoxicity studies (WST-1 and LDH assays) demonstrated that the hybrid nanofibers have suitable biocompatibility. Fluorescence microscopy, also suggested that L929 cells seeded on top of the CH/P hybrid have similar metabolic activity comparatively to the cells seeded on tissue culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system. PMID:27286632

  15. Linking Phospholipid flippases to vesicle-mediated protein transport

    PubMed Central

    Muthusamy, Baby-Periyanayaki; Natarajan, Paramasivam; Zhou, Xiaoming; Graham, Todd R.

    2013-01-01

    Type IV P-type ATPases (P4-ATPases) are a large family of putative phospholipid translocases (flippases) implicated in the generation of phospholipid asymmetry in biological membranes. P4-ATPases are typically the largest P-type ATPase subgroup found in eukaryotic cells, with five members in Saccharomyces cerevisiae, six members in Caenorhabditis elegans, 12 members in Arabidopsis thaliani and 14 members in humans. In addition, many of the P4-ATPases require interaction with a noncatalytic subunit from the CDC50 gene family for their transport out of the endoplasmic reticulum (ER). Deficiency of a P4-ATPase (Atp8b1) causes liver disease in humans, and studies in a variety of model systems indicate that P4-ATPases play diverse and essential roles in membrane biogenesis. In addition to their proposed role in establishing and maintaining plasma membrane asymmetry, P4-ATPases are linked to vesicle-mediated protein transport in the exocytic and endocytic pathways. Recent studies have also suggested a role for P4-ATPases in the nonvesicular intracellular trafficking of sterols. Here, we discuss the physiological requirements for yeast P4-ATPases in phospholipid translocase activity, transport vesicle budding and ergosterol metabolism, with an emphasis on Drs2p and its noncatalytic subunit, Cdc50p. PMID:19286470

  16. Reconstitution of rat liver vasopressin receptors into phospholipid vesicles

    SciTech Connect

    Dickey, B.; Navarro, J.; Fishman, J.; Fine, R.

    1986-05-01

    Isolation and characterization of the hepatic vasopressin (V1) receptor has been hampered by the loss of vasopressin binding when the receptor is solubilized. An alternative to a soluble binding assay is reconstitution of solubilized receptors into phospholipid vesicles. They report here the initial reconstitution of solubilized vasopressin receptors. Rat liver microsomes were solubilized with 3% 3-((3-cholamido-propyl)dimethyl-ammonio)-1-propanesulfonate (CHAPS) in 20mM HEPES (pH 7.4). The solubilized protein was combined with an equal volume of 7% soybean phospholipids dissolved in 3% CHAPS. This solution was passed over a column of Sephadex G50 equilibrated with 30 mM HEPES, 5mM MgCl/sub 2/ (pH 7.4). Reconstituted vesicles containing the microsomal proteins were recovered in the void volume. Binding of (/sup 3/H)-Vasopressin to the reconstituted vesicles at pH 7.4 was 80% specific, saturable, reversible and required magnesium. Solubilization of microsomes in the presence of glycerol, prebound ligand, phospholipids or magnesium did not improve subsequent binding. This reconstitution procedure will allow examination of signal transduction mechanisms and may be used as a functional assay in isolating the receptor.

  17. Label free detection of phospholipids by infrared absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Ahmed, Tahsin; Foster, Erick; Vigil, Genevieve; Khan, Aamir A.; Bohn, Paul; Howard, Scott S.

    2014-08-01

    We present our study on compact, label-free dissolved lipid sensing by combining capillary electrophoresis separation in a PDMS microfluidic chip online with mid-infrared (MIR) absorption spectroscopy for biomarker detection. On-chip capillary electrophoresis is used to separate the biomarkers without introducing any extrinsic contrast agent, which reduces both cost and complexity. The label free biomarker detection could be done by interrogating separated biomarkers in the channel by MIR absorption spectroscopy. Phospholipids biomarkers of degenerative neurological, kidney, and bone diseases are detectable using this label free technique. These phospholipids exhibit strong absorption resonances in the MIR and are present in biofluids including urine, blood plasma, and cerebrospinal fluid. MIR spectroscopy of a 12-carbon chain phosphatidic acid (PA) (1,2-dilauroyl-snglycero- 3-phosphate (sodium salt)) dissolved in N-methylformamide, exhibits a strong amide peak near wavenumber 1660 cm-1 (wavelength 6 μm), arising from the phosphate headgroup vibrations within a low-loss window of the solvent. PA has a similar structure to many important phospholipids molecules like phosphatidylcholine (PC), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and phosphatidylserine (PS), making it an ideal molecule for initial proof-of-concept studies. This newly proposed detection technique can lead us to minimal sample preparation and is capable of identifying several biomarkers from the same sample simultaneously.

  18. Synaptogenesis: Modulation by Availability of Membrane Phospholipid Precursors.

    PubMed

    Cansev, Mehmet

    2016-09-01

    Phospholipids are the main constituents of brain membranes. Formation of new membranes requires that uridine, the omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA), and choline, the three circulating precursors of major phospholipids, interact via the Kennedy pathway. Supplementation of laboratory rodents with uridine, DHA and choline enhances the amount of brain membranes as well as synaptic proteins and increases the number of dendritic spines, the essential cytological precursor of new synapses. Hence, the newly formed membranes are utilized for synaptogenesis which underlies increased synaptic functioning evidenced by enhanced neurotransmission and cognition. In addition, this supplementation ameliorates the degeneration in a rat model of Parkinson's disease and mouse models of Alzheimer's disease (AD) when used in combination with several vitamins and cofactors. Hence, accumulating evidence shows that increasing the availability of phospholipid precursors, vitamins and cofactors to the brain through dietary supplementation enhances the formation of new synapses and provides protection under neurodegenerative conditions. The combination has been tested in clinical trials and a medication has been marketed for early-stage AD patients. PMID:27250850

  19. Proton/hydroxide conductance and permeability through phospholipid bilayer membranes.

    PubMed Central

    Gutknecht, J

    1987-01-01

    Proton/hydroxide (H+/OH-) permeability of phospholipid bilayers is several orders of magnitude higher than alkali or halide ion permeabilities at pH 7. The objective of this study was to determine the mechanism(s) of H+/OH- conductance and permeability through planar phospholipid bilayer membranes. Membranes were formed from decane solutions of bacterial phosphatidylethanolamine, diphytanoyl phosphatidylcholine, or egg phosphatidylcholine plus cholesterol. At pH 7, H+/OH- conductance (GH/OH) ranged from 2 to 6 nS.cm-2, corresponding to H+/OH- "net" permeabilities of (0.4-1.6) X 10(-5) cm.sec-1. GH/OH was inhibited by serum albumin (fatty acid-free), phloretin, and low pH. GH/OH was increased by chlorodecane, long-chain fatty acids, and voltages greater than 80 mV. Water permeability and GH/OH were not correlated. The results suggest that the H+/OH- charge carrier (i) is primarily anionic, (ii) crosses the membrane via nonpolar pathway(s), and (iii) can be removed from the membrane by "washing" with serum albumin. The simplest explanation is that the phospholipids contain weakly acidic contaminants that act as proton carriers at neutral pH. However, at low pH or in the presence of inhibitors, a "background" GH/OH remains that may be due to other mechanisms. PMID:2819878

  20. PRECEDENTS FOR AUTHORIZATION OF CONTENTS USING DOSE RATE MEASUREMENTS

    SciTech Connect

    Abramczyk, G.; Bellamy, S.; Nathan, S.; Loftin, B.

    2012-06-05

    For the transportation of Radioactive Material (RAM) packages, the requirements for the maximum allowed dose rate at the package surface and in its vicinity are given in Title 10 of the Code of Federal Regulations, Section 71.47. The regulations are based on the acceptable dose rates to which the public, workers, and the environment may be exposed. As such, the regulations specify dose rates, rather than quantity of radioactive isotopes and require monitoring to confirm the requirements are met. 10CFR71.47 requires that each package of radioactive materials offered for transportation must be designed and prepared for shipment so that under conditions normally incident to transportation the radiation level does not exceed 2 mSv/h (200 mrem/h) at any point on the external Surface of the package, and the transport index does not exceed 10. Before shipment, the dose rate of the package is determined by measurement, ensuring that it conforms to the regulatory limits, regardless of any analyses. This is the requirement for all certified packagings. This paper discusses the requirements for establishing the dose rates when shipping RAM packages and the precedents for meeting these requirements by measurement.

  1. Self-face enhances processing of immediately preceding invisible faces.

    PubMed

    Pannese, Alessia; Hirsch, Joy

    2011-02-01

    The self-face is thought to be an especially salient stimulus. Behavioral evidence suggests that self-face processing advantage is associated with enhanced processing of temporally adjacent subliminal stimuli. However, the neural basis of this self-related processing modulation has not been investigated. We studied self-face induced signal amplification through masked priming and repetition suppression (fMRI adaptation). Subjects performed a gender-categorization task on self- and non-self target faces preceded by subliminal (17 ms) prime faces. The relationship between prime and target was varied between task-incongruent (when prime and target belonged to a different gender) and task-congruent (when prime and target belonged to the same gender) pairs. We found that, in the presence of the visible self-face (but not of other non-self faces), a bilateral fronto-parietal network exhibited repetition suppression to subliminal prime faces belonging to the same gender (task-congruent) as the target, consistent with the notion that, in the presence of the self-face, subliminal stimuli access high-level processing systems. These results are in agreement with the notion of self-specific top-down amplification of subliminal task-relevant information, and suggest that the self-face, through its high salience, is particularly efficacious in focusing attention. PMID:21168427

  2. High rates of evolution preceded the origin of birds.

    PubMed

    Puttick, Mark N; Thomas, Gavin H; Benton, Michael J

    2014-05-01

    The origin of birds (Aves) is one of the great evolutionary transitions. Fossils show that many unique morphological features of modern birds, such as feathers, reduction in body size, and the semilunate carpal, long preceded the origin of clade Aves, but some may be unique to Aves, such as relative elongation of the forelimb. We study the evolution of body size and forelimb length across the phylogeny of coelurosaurian theropods and Mesozoic Aves. Using recently developed phylogenetic comparative methods, we find an increase in rates of body size and body size dependent forelimb evolution leading to small body size relative to forelimb length in Paraves, the wider clade comprising Aves and Deinonychosauria. The high evolutionary rates arose primarily from a reduction in body size, as there were no increased rates of forelimb evolution. In line with a recent study, we find evidence that Aves appear to have a unique relationship between body size and forelimb dimensions. Traits associated with Aves evolved before their origin, at high rates, and support the notion that numerous lineages of paravians were experimenting with different modes of flight through the Late Jurassic and Early Cretaceous. PMID:24471891

  3. Development of sprite streamers and preceding halos and elves

    NASA Astrophysics Data System (ADS)

    Sanmiya, Y.; Kobayashi, N.; Kudo, T.; Takahashi, Y.; Sato, M.; Shima, Y.; Yamada, T.; NHK Cosmic Shore Project; Stenbaek-Nielsen, H. C.; McHarg, M. G.; Kanmae, T.; Haaland, R.; Yair, Y.; Lyons, W. A.; Cummer, S. A.

    2012-04-01

    The relationship between diffuse glows such as elves and sprite halos and subsequent discrete structure of sprite streamers is considered to have a key to solve the generation mechanism of streamers. However, it's not easy to image at high frame rate both the diffuse and discrete structures simultaneously, since it requires high sensitivity, high spatial resolution and high signal-to-noise ratio. To capture the real spatial structure of TLEs without influence of atmospheric absorption, aircraft would be one of the best solutions. The aircraft can approach thunderstorm up to a few hundred km or less to image TLEs with high spatial resolution and can carry heavy high-speed cameras with huge size data memories. In the period of June 27 - July 10, 2011, a combined aircraft and ground-based campaign, in support of NHK Cosmic Shore project, was carried with two jet airplanes under collaboration between NHK, Japan Broadcasting Corporation, and universities. On 8 nights out of 16 standing-by, the jets took off from the airport near Denver, Colorado, and an airborne high speed camera captured over 40 TLE events at a frame rate of 8300 /sec. Here we introduce the latest analysis of a very complicated time development of sprite streamers and its relationship to the structures of preceding halos and elves, which are always showing some inhomogeneity, suggesting a mechanism to cause the large variation of sprite features.

  4. Perfect study, poor evidence: interpretation of biases preceding study design.

    PubMed

    Ioannidis, John P A

    2008-07-01

    In the interpretation of research evidence, data that have been accumulated in a specific isolated study are typically examined. However, important biases may precede the study design. A study may be misleading, useless, or even harmful, even though it seems to be perfectly designed, conducted, analyzed, and reported. Some biases pertain to setting the wider research agenda and include poor scientific relevance, minimal clinical utility, or failure to consider prior evidence (non-consideration of prior evidence, biased consideration of prior evidence, or consideration of biased prior evidence). Other biases reflect issues in setting the specific research questions: examples include straw man effects, avoidance of head-to-head comparisons, head-to-head comparisons bypassing demonstration of effectiveness, overpowered studies, unilateral aims (focusing on benefits and neglecting harms), and the approach of the industry towards research as bulk advertisement (including ghost management of the literature). The concerted presence of such biases may have a multiplicative, detrimental impact on the scientific literature. These issues should be considered carefully when interpreting research results. PMID:18582622

  5. Early Axonopathy Preceding Neurofibrillary Tangles in Mutant Tau Transgenic Mice

    PubMed Central

    Leroy, Karelle; Bretteville, Alexis; Schindowski, Katharina; Gilissen, Emmanuel; Authelet, Michèle; De Decker, Robert; Yilmaz, Zehra; Buée, Luc; Brion, Jean-Pierre

    2007-01-01

    Neurodegenerative diseases characterized by brain and spinal cord involvement often show widespread accumulations of tau aggregates. We have generated a transgenic mouse line (Tg30tau) expressing in the forebrain and the spinal cord a human tau protein bearing two pathogenic mutations (P301S and G272V). These mice developed age-dependent brain and hippocampal atrophy, central and peripheral axonopathy, progressive motor impairment with neurogenic muscle atrophy, and neurofibrillary tangles and had decreased survival. Axonal spheroids and axonal atrophy developed early before neurofibrillary tangles. Neurofibrillary inclusions developed in neurons at 3 months and were of two types, suggestive of a selective vulnerability of neurons to form different types of fibrillary aggregates. A first type of tau-positive neurofibrillary tangles, more abundant in the forebrain, were composed of ribbon-like 19-nm-wide filaments and twisted paired helical filaments. A second type of tau and neurofilament-positive neurofibrillary tangles, more abundant in the spinal cord and the brainstem, were composed of 10-nm-wide neurofilaments and straight 19-nm filaments. Unbiased stereological analysis indicated that total number of pyramidal neurons and density of neurons in the lumbar spinal cord were not reduced up to 12 months in Tg30tau mice. This Tg30tau model thus provides evidence that axonopathy precedes tangle formation and that both lesions can be dissociated from overt neuronal loss in selected brain areas but not from neuronal dysfunction. PMID:17690183

  6. Neurological Evidence Linguistic Processes Precede Perceptual Simulation in Conceptual Processing

    PubMed Central

    Louwerse, Max; Hutchinson, Sterling

    2012-01-01

    There is increasing evidence from response time experiments that language statistics and perceptual simulations both play a role in conceptual processing. In an EEG experiment we compared neural activity in cortical regions commonly associated with linguistic processing and visual perceptual processing to determine to what extent symbolic and embodied accounts of cognition applied. Participants were asked to determine the semantic relationship of word pairs (e.g., sky – ground) or to determine their iconic relationship (i.e., if the presentation of the pair matched their expected physical relationship). A linguistic bias was found toward the semantic judgment task and a perceptual bias was found toward the iconicity judgment task. More importantly, conceptual processing involved activation in brain regions associated with both linguistic and perceptual processes. When comparing the relative activation of linguistic cortical regions with perceptual cortical regions, the effect sizes for linguistic cortical regions were larger than those for the perceptual cortical regions early in a trial with the reverse being true later in a trial. These results map upon findings from other experimental literature and provide further evidence that processing of concept words relies both on language statistics and on perceptual simulations, whereby linguistic processes precede perceptual simulation processes. PMID:23133427

  7. Activation of ras oncogenes preceding the onset of neoplasia

    SciTech Connect

    Kumar, R.; Barbacid, M. ); Sukumar, S. )

    1990-06-01

    The identification of ras oncogenes in human and animal cancers including precancerous lesions indicates that these genes participate in the early stages of neoplastic development. Yet, these observations do not define the timing of ras oncogene activation in the multistep process of carcinogenesis. To ascertain the timing of ras oncogene activation, an animal model system was devised that involves the induction of mammary carcinomas in rats exposed at birth to the carcinogen nitrosomethylurea. High-resolution restriction fragment length polymorphism analysis of polymerase chain reaction-amplified ras sequences revealed the presence of both H-ras and K-ras oncogenes in normal mammary glands 2 weeks after carcinogen treatment and at least 2 months before the onset of neoplasia. These ras oncogenes can remain latent within the mammary gland until exposure to estrogens, demonstrating that activation of ras oncogenes can precede the onset of neoplasia and suggesting that normal physiological proliferative processes such as estrogen-induced mammary gland development may lead to neoplasia if the targeted cells harbor latent ras oncogenes.

  8. Quantification of myo-inositol, 1,5-anhydro- D-sorbitol, and D-chiro-inositol using high-performance liquid chromatography with electrochemical detection in very small volume clinical samples.

    PubMed

    Schimpf, Karen J; Meek, Claudia C; Leff, Richard D; Phelps, Dale L; Schmitz, Daniel J; Cordle, Christopher T

    2015-11-01

    Inositol is a six-carbon sugar alcohol and is one of nine biologically significant isomers of hexahydroxycyclohexane. Myo-inositol is the primary biologically active form and is present in higher concentrations in the fetus and newborn than in adults. It is currently being examined for the prevention of retinopathy of prematurity in newborn preterm infants. A robust method for quantifying myo-inositol (MI), D-chiro-inositol (DCI) and 1,5-anhydro- D-sorbitol (ADS) in very small-volume (25 μL) urine, blood serum and/or plasma samples was developed. Using a multiple-column, multiple mobile phase liquid chromatographic system with electrochemical detection, the method was validated with respect to (a) selectivity, (b) accuracy/recovery, (c) precision/reproducibility, (d) sensitivity, (e) stability and (f) ruggedness. The standard curve was linear and ranged from 0.5 to 30 mg/L for each of the three analytes. Above-mentioned performance measures were within acceptable limits described in the Food and Drug Administration's Guidance for Industry: Bioanalytical Method Validation. The method was validated using blood serum and plasma collected using four common anticoagulants, and also by quantifying the accuracy and sensitivity of MI measured in simulated urine samples recovered from preterm infant diaper systems. The method performs satisfactorily measuring the three most common inositol isomers on 25 μL clinical samples of serum, plasma, milk, and/or urine. Similar performance is seen testing larger volume samples of infant formulas and infant formula ingredients. MI, ADS and DCI may be accurately tested in urine samples collected from five different preterm infant diapers if the urine volume is greater than 2-5 mL. PMID:26010453

  9. Role of Inositol Phosphosphingolipid Phospholipase C1, the Yeast Homolog of Neutral Sphingomyelinases in DNA Damage Response and Diseases.

    PubMed

    Tripathi, Kaushlendra

    2015-01-01

    Sphingolipids play a very crucial role in many diseases and are well-known as signaling mediators in many pathways. Sphingolipids are produced during the de novo process in the ER (endoplasmic reticulum) from the nonsphingolipid precursor and comprise both structural and bioactive lipids. Ceramide is the central core of the sphingolipid pathway, and its production has been observed following various treatments that can induce several different cellular effects including growth arrest, DNA damage, apoptosis, differentiation, and senescence. Ceramides are generally produced through the sphingomyelin hydrolysis and catalyzed by the enzyme sphingomyelinase (SMase) in mammals. Presently, there are many known SMases and they are categorized into three groups acid SMases (aSMases), alkaline SMases (alk-SMASES), and neutral SMases (nSMases). The yeast homolog of mammalians neutral SMases is inositol phosphosphingolipid phospholipase C. Yeasts generally have inositol phosphosphingolipids instead of sphingomyelin, which may act as a homolog of mammalian sphingomyelin. In this review, we shall explain the structure and function of inositol phosphosphingolipid phospholipase C1, its localization inside the cells, mechanisms, and its roles in various cell responses during replication stresses and diseases. This review will also give a new basis for our understanding for the mechanisms and nature of the inositol phosphosphingolipid phospholipase C1/nSMase. PMID:26346287

  10. Raman spectra of organic (myo-inositol hexakis phosphate) and inorganic P sepctra show pH dependence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding phosphorous fate and transport is in part limited by technical difficulties and/or access to expensive equipment associated with differentiating ortho-phosphate (P) from organic phosphate in complex environmental samples. Myo-inositol hexakis phosphate (IHP) is the most prevalent form...

  11. Identification and Quantitation of Various Inositols and O-methylinositols Present in Plant Roots Using Gas Chromatograpghy/Mass Spectrometry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many inositols and O-methylinositols serve important roles in medicine and plant biology. A simple method was developed for the identification of these compounds in plant roots by extracting with 80% ethanol, derivatizing with trimethylsilyl imidazole, and analyzing by gas chromatography/mass spect...

  12. Supplementation of plant-based diets for rainbow trout, Oncorhynchus mykiss with macro-minerals and inositol.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replacement of fish meal with plant products in aquafeeds results in the elimination of dietary compounds which may be important for optimal growth and physiology. A study was conducted to determine if supplementation with macro-minerals and/or inositol would improve performance of rainbow trout fe...

  13. An improved Bacillus subtilis cell factory for producing scyllo-inositol, a promising therapeutic agent for Alzheimer’s disease

    PubMed Central

    2013-01-01

    Background Bacillus subtilis 168 possesses an efficient pathway to metabolize some of the stereoisomers of inositol, including myo-inositol (MI) and scyllo-inositol (SI). Previously we reported a prototype of a B. subtilis cell factory with modified inositol metabolism that converts MI into SI in the culture medium. However, it wasted half of initial 1.0% (w/v) MI, and the conversion was limited to produce only 0.4% (w/v) SI. To achieve a more efficient SI production, we attempted additional modifications. Results All “useless” genes involved in MI and SI metabolism were deleted. Although no elevation in SI production was observed in the deletion strain, it did result in no wastage of MI anymore. Thus additionally, overexpression of the key enzymes, IolG and IolW, was appended to demonstrate that simultaneous overexpression of them enabled complete conversion of all MI into SI. Conclusions The B. subtilis cell factory was improved to yield an SI production rate of 10 g/L/48 h at least. The improved conversion was achieved only in the presence of enriched nutrition in the form of 2% (w/v) Bacto soytone in the medium, which may be due to the increasing demand for regeneration of cofactors. PMID:24325193

  14. Nomenclature Committee of the International Union of Biochemistry (NC-IUB). Numbering of atoms in myo-inositol. Recommendations 1988.

    PubMed

    1989-04-01

    A relaxation of previous recommendations on the numbering of the atoms of myo-inositol is suggested: substituents need not necessarily be numbered so that the smallest possible locant is used. This allows an alternative designation to be used, when authors wish, to bring out structural relationships. PMID:2714267

  15. Numbering of atoms in myo-inositol. Recommendations 1988. Nomenclature Committee of the International Union of Biochemistry.

    PubMed

    1989-02-15

    A relaxation of previous recommendations on the numbering of the atoms of myo-inositol is suggested, so that substituents are not necessarily numbered so that the smallest possible locant is used. This allows an alternative designation to be used, when authors wish, to bring out structural relationships. PMID:2930499

  16. Involvement of Inositol Biosynthesis and Nitric Oxide in the Mediation of UV-B Induced Oxidative Stress

    PubMed Central

    Lytvyn, Dmytro I.; Raynaud, Cécile; Yemets, Alla I.; Bergounioux, Catherine; Blume, Yaroslav B.

    2016-01-01

    The involvement of NO-signaling in ultraviolet B (UV-B) induced oxidative stress (OS) in plants is an open question. Inositol biosynthesis contributes to numerous cellular functions, including the regulation of plants tolerance to stress. This work reveals the involvement of inositol-3-phosphate synthase 1 (IPS1), a key enzyme for biosynthesis of myo-inositol and its derivatives, in the response to NO-dependent OS in Arabidopsis. Homozygous mutants deficient for IPS1 (atips1) and wild-type plants were transformed with a reduction- grx1-rogfp2 and used for the dynamic measurement of UV-B-induced and SNP (sodium nitroprusside)-mediated oxidative stresses by confocal microscopy. atips1 mutants displayed greater tissue-specific resistance to the action of UV-B than the wild type. SNP can act both as an oxidant or repairer depending on the applied concentration, but mutant plants were more tolerant than the wild type to nitrosative effects of high concentration of SNP. Additionally, pretreatment with low concentrations of SNP (10, 100 μM) before UV-B irradiation resulted in a tissue-specific protective effect that was enhanced in atips1. We conclude that the interplay between nitric oxide and inositol signaling can be involved in the mediation of UV-B-initiated oxidative stress in the plant cell. PMID:27148278

  17. A limitation of the continuous spectrophotometric assay for the measurement of myo-inositol-1-phosphate synthase activity.

    PubMed

    Huang, Xinyi; Hernick, Marcy

    2011-10-15

    Myo-inositol-1-phosphate synthase (MIPS) catalyzes the conversion of glucose-6-phosphate to myo-inositol-1-phosphate. The reaction catalyzed by MIPS is the first step in the biosynthesis of inositol and inositol-containing molecules that serve important roles in both eukaryotes and prokaryotes. Consequently, MIPS is a target for the development of therapeutic agents for the treatment of infectious diseases and bipolar disorder. We recently reported a continuous spectrophotometric method for measuring MIPS activity using a coupled assay that allows the rapid characterization of MIPS in a multiwell plate format. Here we validate the continuous assay as a high-throughput alternative for measuring MIPS activity and report on one limitation of this assay-the inability to examine the effect of divalent metal ions (at high concentrations) on MIPS activity. In addition, we demonstrate that the activity of MIPS from Arabidopsis thaliana is moderately enhanced by the addition Mg(2+) and is not enhanced by other divalent metal ions (Zn(2+) and Mn(2+)), consistent with what has been observed for other eukaryotic MIPS enzymes. Our findings suggest that the continuous assay is better suited for characterizing eukaryotic MIPS enzymes that require monovalent cations as cofactors than for characterizing bacterial or archeal MIPS enzymes that require divalent metal ions as cofactors. PMID:21729692

  18. Combination of inositol and alpha lipoic acid in metabolic syndrome-affected women: a randomized placebo-controlled trial

    PubMed Central

    2013-01-01

    Background Inositol has been reported to improve insulin sensitivity since it works as a second messenger achieving insulin-like effects on metabolic enzymes. The aim of this study was to evaluate the inositol and alpha lipoic acid combination effectiveness on metabolic syndrome features in postmenopausal women at risk of breast cancer. Methods A six-month prospective, randomized placebo-controlled trial was carried out on a total of 155 postmenopausal women affected by metabolic syndrome at risk of breast cancer, the INOSIDEX trial. All women were asked to follow a low-calorie diet and were assigned randomly to daily consumption of a combination of inositol and alpha lipoic acid (77 pts) or placebo (78 pts) for six months. Primary outcomes we wanted to achieve were both reduction of more than 20% of the HOMA-IR index and of triglycerides serum levels. Secondary outcomes expected were both the improvement of high-density lipoprotein cholesterol levels and the reduction of anthropometric features such as body mass index and waist-hip ratio. Results A significant HOMA-IR reduction of more than 20% was evidenced in 66.7% (P <0.0001) of patients, associated with a serum insulin level decrease in 89.3% (P <0.0000). A decrease in triglycerides was evidenced in 43.2% of patients consuming the supplement (P <0.0001). An increase in HDL cholesterol (48.6%) was found in the group consuming inositol with respect to the placebo group. A reduction in waist circumference and waist-hip ratio was found in the treated group with respect to the placebo group. Conclusions Inositol combined with alpha lipoic acid can be used as a dietary supplement in insulin-resistant patients in order to increase their insulin sensitiveness. Daily consumption of inositol combined with alpha lipoic acid has a significant bearing on metabolic syndrome. As metabolic syndrome is considered a modifiable risk factor of breast tumorigenesis, further studies are required to assess whether inositol combined

  19. Inositol trisphosphate 3-kinase B is increased in human Alzheimer brain and exacerbates mouse Alzheimer pathology.

    PubMed

    Stygelbout, Virginie; Leroy, Karelle; Pouillon, Valérie; Ando, Kunie; D'Amico, Eva; Jia, Yonghui; Luo, H Robert; Duyckaerts, Charles; Erneux, Christophe; Schurmans, Stéphane; Brion, Jean-Pierre

    2014-02-01

    ITPKB phosphorylates inositol 1,4,5-trisphosphate into inositol 1,3,4,5-tetrakisphosphate and controls signal transduction in various hematopoietic cells. Surprisingly, it has been reported that the ITPKB messenger RNA level is significantly increased in the cerebral cortex of patients with Alzheimer's disease, compared with control subjects. As extracellular signal-regulated kinases 1/2 activation is increased in the Alzheimer brain and as ITPKB is a regulator of extracellular signal-regulated kinases 1/2 activation in some hematopoietic cells, we tested whether this increased activation in Alzheimer's disease might be related to an increased activity of ITPKB. We show here that ITPKB protein level was increased 3-fold in the cerebral cortex of most patients with Alzheimer's disease compared with control subjects, and accumulated in dystrophic neurites associated to amyloid plaques. In mouse Neuro-2a neuroblastoma cells, Itpkb overexpression was associated with increased cell apoptosis and increased β-secretase 1 activity leading to overproduction of amyloid-β peptides. In this cellular model, an inhibitor of mitogen-activated kinase kinases 1/2 completely prevented overproduction of amyloid-β peptides. Transgenic overexpression of ITPKB in mouse forebrain neurons was not sufficient to induce amyloid plaque formation or tau hyperphosphorylation. However, in the 5X familial Alzheimer's disease mouse model, neuronal ITPKB overexpression significantly increased extracellular signal-regulated kinases 1/2 activation and β-secretase 1 activity, resulting in exacerbated Alzheimer's disease pathology as shown by increased astrogliosis, amyloid-β40 peptide production and tau hyperphosphorylation. No impact on pathology was observed in the 5X familial Alzheimer's disease mouse model when a catalytically inactive ITPKB protein was overexpressed. Together, our results point to the ITPKB/inositol 1,3,4,5-tetrakisphosphate/extracellular signal-regulated kinases 1

  20. Phosphotransferase system-independent glucose utilization in corynebacterium glutamicum by inositol permeases and glucokinases.

    PubMed

    Lindner, Steffen N; Seibold, Gerd M; Henrich, Alexander; Krämer, Reinhard; Wendisch, Volker F

    2011-06-01

    Phosphoenolpyruvate-dependent glucose phosphorylation via the phosphotransferase system (PTS) is the major path of glucose uptake in Corynebacterium glutamicum, but some growth from glucose is retained in the absence of the PTS. The growth defect of a deletion mutant lacking the general PTS component HPr in glucose medium could be overcome by suppressor mutations leading to the high expression of inositol utilization genes or by the addition of inositol to the growth medium if a glucokinase is overproduced simultaneously. PTS-independent glucose uptake was shown to require at least one of the inositol transporters IolT1 and IolT2 as a mutant lacking IolT1, IolT2, and the PTS component HPr could not grow with glucose as the sole carbon source. Efficient glucose utilization in the absence of the PTS necessitated the overexpression of a glucokinase gene in addition to either iolT1 or iolT2. IolT1 and IolT2 are low-affinity glucose permeases with K(s) values of 2.8 and 1.9 mM, respectively. As glucose uptake and phosphorylation via the PTS differs from glucose uptake via IolT1 or IolT2 and phosphorylation via glucokinase by the requirement for phosphoenolpyruvate, the roles of the two pathways for l-lysine production were tested. The l-lysine yield by C. glutamicum DM1729, a rationally engineered l-lysine-producing strain, was lower than that by its PTS-deficient derivate DM1729Δhpr, which, however, showed low production rates. The combined overexpression of iolT1 or iolT2 with ppgK, the gene for PolyP/ATP-dependent glucokinase, in DM1729Δhpr enabled l-lysine production as fast as that by the parent strain DM1729 but with 10 to 20% higher l-lysine yield. PMID:21478323

  1. A Novel Inositol Pyrophosphate Phosphatase in Saccharomyces cerevisiae: Siw14 PROTEIN SELECTIVELY CLEAVES THE β-PHOSPHATE FROM 5-DIPHOSPHOINOSITOL PENTAKISPHOSPHATE (5PP-IP5).

    PubMed

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

    2016-03-25

    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, theSaccharomyces cerevisiaehomolog 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-IP5or IP7)in vitro. In vivo,siw14Δ yeast mutants possess increased IP7levels, whereas heterologousSIW14overexpression eliminates IP7from cells. IP7levels increased proportionately whensiw14Δ was combined withddp1Δ orvip1Δ, 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 IP7isoform 5PP-IP5to IP6. PMID:26828065

  2. The separation of ( sup 32 P)inositol phosphates by ion-pair chromatography: Optimization of the method and biological applications

    SciTech Connect

    Sulpice, J.C.; Gascard, P.; Journet, E.; Rendu, F.; Renard, D.; Poggioli, J.; Giraud, F. )

    1989-05-15

    We have developed an ion-pair reverse-phase HPLC method to measure inositol phosphates in {sup 32}P-labeled cells. The different chromatographic parameters were analyzed to optimize the resolution of the {sup 32}P-labeled metabolites. Analysis of inositol phosphates in biological samples was improved by a single charcoal pretreatment which eliminated interfering nucleotides without removing inositol phosphates. The kinetics of production of inositol phosphates in calcium-activated erythrocytes, vasopressin-stimulated hepatocytes, and thrombin-activated platelets were analyzed. Original data on the activation of phosphoinositide phospholipase C were obtained in intact erythrocytes by direct measurement of inositol (1,4,5)P3. Data from agonist-stimulated hepatocytes and platelets were consistent with those from previous studies. In conclusion, this technique offers many advantages over the methodologies currently employed involving anion-exchange chromatography and ({sup 3}H)inositol labeling: (i) {sup 32}P labeling is less expensive and more efficient than {sup 3}H labeling and can be used with all types of cells without permeabilization treatments and (ii) ion-pair HPLC gives good resolution of inositol phosphates from nucleotides with shorter retention times, and long reequilibration periods are not required.

  3. A defect in sodium-dependent amino acid uptake in diabetic rabbit peripheral nerve. Correction by an aldose reductase inhibitor or myo-inositol administration.

    PubMed Central

    Greene, D A; Lattimer, S A; Carroll, P B; Fernstrom, J D; Finegold, D N

    1990-01-01

    A myo-inositol-related defect in nerve sodium-potassium ATPase activity in experimental diabetes has been suggested as a possible pathogenetic factor in diabetic neuropathy. Because the sodium-potassium ATPase is essential for other sodium-cotransport systems, and because myo-inositol-derived phosphoinositide metabolites regulate multiple membrane transport processes, sodium gradient-dependent amino acid uptake was examined in vitro in endoneurial preparations derived from nondiabetic and 14-d alloxan diabetic rabbits. Untreated alloxan diabetes reduced endoneurial sodium-gradient dependent uptake of the nonmetabolized amino acid 2-aminoisobutyric acid by greater than 50%. Administration of an aldose reductase inhibitor prevented reductions in both nerve myo-inositol content and endoneurial sodium-dependent 2-aminoisobutyric acid uptake. Myo-inositol supplementation that produced a transient pharmacological elevation in plasma myo-inositol concentration, but did not raise nerve myo-inositol content, reproduced the effect of the aldose reductase inhibitor on endoneurial sodium-dependent 2-aminoisobutyric acid uptake. Phorbol myristate acetate, which acutely normalizes sodium-potassium ATPase activity in diabetic nerve, did not acutely correct 2-aminoisobutyric uptake when added in vitro. These data suggest that depletion of a small myo-inositol pool may be implicated in the pathogenesis of defects in amino acid uptake in diabetic nerve and that rapid correction of sodium-potassium ATPase activity with protein kinase C agonists in vitro does not acutely normalize sodium-dependent 2-aminoisobutyric acid uptake. PMID:2185278

  4. Effect of co-solutes and process variables on crystallinity and the crystal form of freeze-dried myo-inositol.

    PubMed

    Izutsu, Ken-Ichi; Kusano, Riho; Arai, Ryoko; Yoshida, Hiroyuki; Ito, Masataka; Shibata, Hiroko; Sugano, Kiyohiko; Goda, Yukihiro; Terada, Katsuhide

    2016-07-25

    The purpose of this study was to elucidate how co-solutes affect the crystallization of small solute molecules during freeze-drying and subsequent storage. Crystallization profiles of myo-inositol and its mixture with dextran 40k in frozen solutions and dried solids were assessed by thermal analysis (DSC), powder-X-ray diffraction, and simultaneous DSC and PXRD analysis. Higher mass ratios of dextran maintained myo-inositol in the non-crystalline mixture state, in frozen solutions, during freeze-drying process, and exposure of dried solids to higher temperatures. Co-lyophilization with a lower mass ratio of dextran resulted in solids containing a variety of myo-inositol crystal forms and crystallinity depending on the composition and thermal history of the process. Heating of some inositol-rich amorphous solids showed crystallization of myo-inositol in the metastable form and its transition to stable form before melting. Heat-treatment of inositol-rich frozen solutions resulted in high crystallinity stable-form inositol solids, leaving dextran in the amorphous state. Sufficient direct molecular interactions (e.g., hydrogen bonding) should explain the stability of dextran-rich amorphous solids. Optimizing solute composition and processes should be a potent way to control crystal form and crystallinity of components in freeze-dried formulations. PMID:27282535

  5. The Phosphatidyl-myo-Inositol Mannosyltransferase PimA Is Essential for Mycobacterium tuberculosis Growth In Vitro and In Vivo

    PubMed Central

    Boldrin, Francesca; Ventura, Marcello; Degiacomi, Giulia; Ravishankar, Sudha; Sala, Claudia; Svetlikova, Zuzana; Ambady, Anisha; Dhar, Neeraj; Kordulakova, Jana; Zhang, Ming; Serafini, Agnese; Vishwas, V. G.; Kolly, Gaëlle S.; Kumar, Naveen; Palù, Giorgio; Guerin, Marcelo E.; Mikusova, Katarina; Cole, Stewart T.

    2014-01-01

    The cell envelope of Mycobacterium tuberculosis contains glycans and lipids of peculiar structure that play prominent roles in the biology and pathogenesis of tuberculosis. Consequently, the chemical structure and biosynthesis of the cell wall have been intensively investigated in order to identify novel drug targets. Here, we validate that the function of phosphatidyl-myo-inositol mannosyltransferase PimA is vital for M. tuberculosis in vitro and in vivo. PimA initiates the biosynthesis of phosphatidyl-myo-inositol mannosides by transferring a mannosyl residue from GDP-Man to phosphatidyl-myo-inositol on the cytoplasmic side of the plasma membrane. To prove the essential nature of pimA in M. tuberculosis, we constructed a pimA conditional mutant by using the TetR-Pip off system and showed that downregulation of PimA expression causes bactericidality in batch cultures. Consistent with the biochemical reaction catalyzed by PimA, this phenotype was associated with markedly reduced levels of phosphatidyl-myo-inositol dimannosides, essential structural components of the mycobacterial cell envelope. In addition, the requirement of PimA for viability was clearly demonstrated during macrophage infection and in two different mouse models of infection, where a dramatic decrease in viable counts was observed upon silencing of the gene. Notably, depletion of PimA resulted in complete clearance of the mouse lungs during both the acute and chronic phases of infection. Altogether, the experimental data highlight the importance of the phosphatidyl-myo-inositol mannoside biosynthetic pathway for M. tuberculosis and confirm that PimA is a novel target for future drug discovery programs. PMID:25049093

  6. Osmotic regulation and tissue localization of the myo-inositol biosynthesis pathway in tilapia (Oreochromis mossambicus) larvae.

    PubMed

    Sacchi, Romina; Gardell, Alison M; Chang, Nicole; Kültz, Dietmar

    2014-10-01

    The myo-inositol biosynthesis (MIB) pathway converts glucose-6-phosphate to the compatible osmolyte myo-inositol, which protects cells from salinity stress. We exposed tilapia larvae just after yolk sac resorption to various hypersaline environments and recorded robust induction of the enzymes that constitute the MIB pathway, myo-inositol-phosphate synthase (MIPS), and inositol monophosphatase 1 (IMPA1). Strong up-regulation of these enzymes is evident at both mRNA (quantitative real-time PCR) and protein (densitometric analysis of Western blots) levels. The highest level of induction of these enzymes occurs at the highest salinity that larvae were exposed to (90 ppt). Less severe salinity stress causes a proportionately reduced induction of the MIB pathway. Two distinct MIPS mRNA variants are present in tilapia larvae and both are induced at comparable levels for all the salinity challenges tested (34, 70, and 90 ppt). Immunohistochemical localization of IMPA1 protein in sagittal sections of salinity stressed and control larvae identified tissues that are particularly potent in inducing the MIB pathway. These tissues include the skin (epidermis), gills, eye (ciliary epithelium) and heart. In particular, the epidermis directly facing the external milieu showed a very strong induction of IMPA1 immunoreactivity. IMPA1 induction in response to salinity stress was not observed in other tissues suggesting that tilapia larvae may also utilize compatible organic osmolytes other than solely myo-inositol for osmoprotection. We conclude that the MIB pathway plays an important role in protecting multiple (but not all) tissues of tilapia larvae from hyperosmotic salinity stress. PMID:25045088

  7. Mechanism of myo-inositol hexakisphosphate sorption on amorphous aluminum hydroxide: spectroscopic evidence for rapid surface precipitation.

    PubMed

    Yan, Yupeng; Li, Wei; Yang, Jun; Zheng, Anmin; Liu, Fan; Feng, Xionghan; Sparks, Donald L

    2014-06-17

    Inositol hexakisphosphates are the most abundant organic phosphates (OPs) in most soils and sediments. Adsorption, desorption, and precipitation reactions at environmental interfaces govern the reactivity, speciation, mobility, and bioavailability of inositol hexakisphosphates in terrestrial and aquatic environments. However, surface complexation and precipitation reactions of inositol hexakisphosphates on soil minerals have not been well understood. Here we investigate the surface complexation-precipitation process and mechanism of myo-inositol hexakisphosphate (IHP, phytate) on amorphous aluminum hydroxide (AAH) using macroscopic sorption experiments and multiple spectroscopic tools. The AAH (16.01 μmol m(-2)) exhibits much higher sorption density than boehmite (0.73 μmol m(-2)) and α-Al2O3 (1.13 μmol m(-2)). Kinetics of IHP sorption and accompanying OH(-) release, as well as zeta potential measurements, indicate that IHP is initially adsorbed on AAH through inner-sphere complexation via ligand exchange, followed by AAH dissolution and ternary complex formation; last, the ternary complexes rapidly transform to surface precipitates and bulk phase analogous to aluminum phytate (Al-IHP). The pH level, reaction time, and initial IHP loading evidently affect the interaction of IHP on AAH. In situ ATR-FTIR and solid-state NMR spectra further demonstrate that IHP sorbs on AAH and transforms to surface precipitates analogous to Al-IHP, consistent with the results of XRD analysis. This study indicates that active metal oxides such as AAH strongly mediate the speciation and behavior of IHP via rapid surface complexation-precipitation reactions, thus controlling the mobility and bioavailability of inositol phosphates in the environment. PMID:24871399

  8. Oral Hygiene Behaviors and Caries Experience in Northwest PRECEDENT Patients

    PubMed Central

    Rothen, Marilynn; Cunha-Cruz, Joana; Zhou, Lingmei; Mancl, Lloyd; Jones, Jackie S.; Berg, Joel

    2014-01-01

    Objectives To investigate the association between oral hygiene behaviors (toothbrushing, water rinsing after brushing, interproximal cleaning, and adjunctive use of fluoride products) and recent caries (past 24 months) in a random sample of patients in Northwest PRECEDENT practices. Methods Practitioner-members of Northwest PRECEDENT dental Practice-based Research Network (PBRN) conducted a longitudinal study on caries risk assessment. At baseline patients completed a questionnaire on oral self-care, snacking, health, and socio-demographics. A dental exam recorded readily-visible heavy plaque and DMFT; chart review captured new caries and treatments in the previous 24 months. Bivariate and multiple GEE log-linear regression models stratified by age groups were used to relate oral hygiene behaviors to the primary outcome of mean dental caries in the past 24 months on data from 1400 patients in 63 practices. The primary exposure of interest was fluoride toothbrushing frequency. Results Fluoride toothbrushing once per day or more by patients 9-17 was significantly associated with a 50% lower mean caries rate compared to fluoride toothbrushing less than once per day, after adjustment for age, gender, race, education, income, between-meal carbohydrate snacks, sugar-added beverages, alcohol consumption, smoking, BMI, exercise, stimulated salivary pH, number of teeth, and all other oral hygiene behaviors captured [Rate Ratio (RR)=0.5; 95% confidence interval (CI)=0.3-0.8]. After adjustment, for patients 18-64 fluoride toothbrushing two or more times per day was significantly associated with a 40% lower recent mean caries rate (RR=0.6; 95%CI=0.4-0.9); in patients 65+, twice a day or more fluoride toothbrushing was not associated with lower caries rates (RR=1.1; 95%CI=0.7-1.8). Of the other oral hygiene variables, after adjustment, patients 18-64 who rinsed with water after brushing had a 40% lower mean caries rate compared to no rinsing (RR=0.6; 95%CI=0.4-0.9) and the

  9. Integrated Vehicle Ground Vibration Testing of Manned Spacecraft: Historical Precedent

    NASA Technical Reports Server (NTRS)

    Lemke, Paul R.; Tuma, Margaret L.; Askins, Bruce R.

    2008-01-01

    For the first time in nearly 30 years, NASA is developing a new manned space flight launch system. The Ares I will carry crew and cargo to not only the International Space Station, but onward for the future exploration of the Moon and Mars. The Ares I control system and structural designs use complex computer models for their development. An Integrated Vehicle Ground Vibration Test (IVGVT) will validate the efficacy of these computer models. The IVGVT will reduce the technical risk of unexpected conditions that could place the vehicle or crew in jeopardy. The Ares Project Office's Flight and Integrated Test Office commissioned a study to determine how historical programs, such as Saturn and Space Shuttle, validated the structural dynamics of an integrated flight vehicle. The study methodology was to examine the historical record and seek out members of the engineering community who recall the development of historic manned launch vehicles. These records and interviews provided insight into the best practices and lessons learned from these historic development programs. The information that was gathered allowed the creation of timelines of the historic development programs. The timelines trace the programs from the development of test articles through test preparation, test operations, and test data reduction efforts. These timelines also demonstrate how the historical tests fit within their overall vehicle development programs. Finally, the study was able to quantify approximate staffing levels during historic development programs. Using this study, the Flight and Integrated Test Office was able to evaluate the Ares I Integrated Vehicle Ground Vibration Test schedule and workforce budgets in light of the historical precedents to determine if the test had schedule or cost risks associated with it.

  10. Impaired cortical mitochondrial function following TBI precedes behavioral changes

    PubMed Central

    Watson, William D.; Buonora, John E.; Yarnell, Angela M.; Lucky, Jessica J.; D’Acchille, Michaela I.; McMullen, David C.; Boston, Andrew G.; Kuczmarski, Andrew V.; Kean, William S.; Verma, Ajay; Grunberg, Neil E.; Cole, Jeffrey T.

    2014-01-01

    Traumatic brain injury (TBI) pathophysiology can be attributed to either the immediate, primary physical injury, or the delayed, secondary injury which begins minutes to hours after the initial injury and can persist for several months or longer. Because these secondary cascades are delayed and last for a significant time period post-TBI, they are primary research targets for new therapeutics. To investigate changes in mitochondrial function after a brain injury, both the cortical impact site and ipsilateral hippocampus of adult male rats 7 and 17 days after a controlled cortical impact (CCI) injury were examined. State 3, state 4, and uncoupler-stimulated rates of oxygen consumption, respiratory control ratios (RCRs) were measured and membrane potential quantified, and all were significantly decreased in 7 day post-TBI cortical mitochondria. By contrast, hippocampal mitochondria at 7 days showed only non-significant decreases in rates of oxygen consumption and membrane potential. NADH oxidase activities measured in disrupted mitochondria were normal in both injured cortex and hippocampus at 7 days post-CCI. Respiratory and phosphorylation capacities at 17 days post-CCI were comparable to naïve animals for both cortical and hippocampus mitochondria. However, unlike oxidative phosphorylation, membrane potential of mitochondria in the cortical lining of the impact site did not recover at 17 days, suggesting that while diminished cortical membrane potential at 17 days does not adversely affect mitochondrial capacity to synthesize ATP, it may negatively impact other membrane potential-sensitive mitochondrial functions. Memory status, as assessed by a passive avoidance paradigm, was not significantly impaired until 17 days after injury. These results indicate pronounced disturbances in cortical mitochondrial function 7 days after CCI which precede the behavioral impairment observed at 17 days. PMID:24550822

  11. Stimulus-preceding negativity represents a conservative response tendency

    PubMed Central

    Hirao, Takahiro; Murphy, Timothy I.

    2016-01-01

    Humans tend to be conservative and typically will retain their initial decision even if an option to change is provided. We investigated whether the stimulus-preceding negativity (SPN), an event-related potential associated with the affective-motivational anticipation of feedback in gambling tasks, represents the strong response tendency to retain an initial decision. We compared SPNs in three different card-gambling tasks wherein the participants were given the opportunity to change their initial decision after they chose one of three cards. In two of these tasks, the winning probability was equiprobable (1/3 and 1/2, respectively) whether or not the participants changed their initial decision. However, in the Monty Hall dilemma task, changing the initial decision stochastically doubled the probability of winning (2/3) compared with retaining (1/3). In this counterintuitive probabilistic dilemma task, after the participant chose an option among three cards, a nonreward (losing) option is revealed. Then, the participants are offered a chance to change their mind and asked to make their final decision: to retain their initial choice or change to the alternate option. In all tasks, maintenance of previous behaviors was observed, although the rate of retaining earlier choices tended to be lower in the Monty Hall dilemma task than in the other two tasks. The SPNs were larger on retain trials than on change trials irrespective of task. These results suggest that underlying brain activities associated with the strong tendency to retain the initial decision can be observed by the SPN and thus it reflects expectancy of outcomes in terms of self-chosen behaviors. PMID:26626414

  12. Increased cerebral oxygenation precedes generalized tonic clonic seizures.

    PubMed

    Moseley, Brian D; Britton, Jeffrey W; So, Elson

    2014-11-01

    Based on previous fMRI and SPECT studies, it has been suggested seizures may be preceded by increased cerebral blood flow. Recently, we demonstrated transcutaneous regional cerebral oxygen saturation (rSO2) sensors are feasible for use in patients undergoing video EEG monitoring. We reanalyzed our data to determine if seizures were consistently marked by increased cerebral oxygenation. Patients with histories of generalized tonic clonic seizures (GTCS) were recruited into our study. All subjects were evaluated with continuous 30-channel scalp EEG and 2 rSO2 sensors placed on each side of the forehead. We calculated the mean rSO2 value for the 1h epochs in the non-ictal (2h prior to seizure onset) and pre-ictal (1h prior to onset) periods. Seven primary/secondarily GTCS from 5 patients were captured. The mean rSO2 value in the non-ictal period was 75.6 ± 5.7%. This increased to 76.0 ± 6% in the pre-ictal period (p=0.032). Four of the 7GTCS (57.1%) were marked by ≥ 3 sequential rSO2 values in the pre-ictal period that were ≥ 3 SDs greater than the mean non-ictal rSO2 value. Three GTCS (42.9%) were marked by sustained cerebral hyperemia for ≥ 15 consecutive readings. Our results suggest increased cerebral blood flow could be non-invasively used to predict seizure occurrence. PMID:25277885

  13. Axonal Dysfunction Precedes Motor Neuronal Death in Amyotrophic Lateral Sclerosis.

    PubMed

    Iwai, Yuta; Shibuya, Kazumoto; Misawa, Sonoko; Sekiguchi, Yukari; Watanabe, Keisuke; Amino, Hiroshi; Kuwabara, Satoshi

    2016-01-01

    Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p < 0.05), greater threshold changes in depolarizing threshold electrotonus (p < 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p < 0.05), greater superexcitability (a measure of fast potassium current; p < 0.05) and reduced late subexcitability (a measure of slow potassium current; p < 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (> 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS. PMID:27383069

  14. Axonal Dysfunction Precedes Motor Neuronal Death in Amyotrophic Lateral Sclerosis

    PubMed Central

    Iwai, Yuta; Shibuya, Kazumoto; Misawa, Sonoko; Sekiguchi, Yukari; Watanabe, Keisuke; Amino, Hiroshi; Kuwabara, Satoshi

    2016-01-01

    Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p < 0.05), greater threshold changes in depolarizing threshold electrotonus (p < 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p < 0.05), greater superexcitability (a measure of fast potassium current; p < 0.05) and reduced late subexcitability (a measure of slow potassium current; p < 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (> 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS. PMID:27383069

  15. Fagopyritol B1, O-alpha-D-galactopyranosyl-(1-->2)-D-chiro-inositol, a galactosyl cyclitol in maturing buckwheat seeds associated with desiccation tolerance.

    PubMed

    Horbowicz, M; Brenac, P; Obendorf, R L

    1998-05-01

    O-alpha-D-Galactopyranosyl-(1-->2)-D-chiro-inositol, herein named fagopyritol B1, was identified as a major soluble carbohydrate (40% of total) in buckwheat (Fagopyrum esculentum Moench, Polygonaceae) embryos. Analysis of hydrolysis products of purified compounds and of the crude extract led to the conclusion that buckwheat embryos have five alpha-galactosyl D-chiro-inositols: fagopyritol A1 and fagopyritol B1 (mono-galactosyl D-chiro-inositol isomers), fagopyritol A2 and fagopyritol B2 (di-galactosyl D-chiro-inositol isomers), and fagopyritol B3 (tri-galactosyl D-chiro-inositol). Other soluble carbohydrates analyzed by high-resolution gas chromatography included sucrose (42% of total), D-chiro-inositol, myo-inositol, galactinol, raffinose and stachyose (1% of total), but no reducing sugars. All fagopyritols were readily hydrolyzed by alpha-galactosidase (EC 3.2.1.22) from green coffee bean, demonstrating alpha-galactosyl linkage. Retention time of fagopyritol B1 was identical to the retention time of O-alpha-D-galactopyranosyl-(1-->2)-D-chiro-inositol from soybean (Glycine max (L.) Merrill, Leguminosae), suggesting that the alpha-galactosyl linkage is to the 2-position of D-chiro-inositol. Accumulation of fagopyritol B1 was associated with acquisition of desiccation tolerance during seed development and maturation in planta, and loss of fagopyritol B1 correlated with loss of desiccation tolerance during germination. Embryos of seeds grown at 18 degrees C, a condition that favors enhanced seed vigor and storability, had a sucrose-to-fagopyritol B1 ratio of 0.8 compared to a ratio of 2.46 for seeds grown at 25 degrees C. We propose that fagopyritol B1 facilitates desiccation tolerance and storability of buckwheat seeds. PMID:9599801

  16. Uncoupling of attenuated myo-(3H)inositol uptake and dysfunction in Na(+)-K(+)-ATPase pumping activity in hypergalactosemic cultured bovine lens epithelial cells

    SciTech Connect

    Cammarata, P.R.; Tse, D.; Yorio, T. )

    1991-06-01

    Attenuation of both the active transport of myo-inositol and Na(+)-K(+)-ATPase pumping activity has been implicated in the onset of sugar cataract and other diabetic complications in cell culture and animal models of the disease. Cultured bovine lens epithelial cells (BLECs) maintained in galactose-free Eagle's minimal essential medium (MEM) or 40 mM galactose with and without sorbinil for up to 5 days were examined to determine the temporal effects of hypergalactosemia on Na(+)-K(+)-ATPase and myo-inositol uptake. The Na(+)-K(+)-ATPase pumping activity after 5 days of continuous exposure to galactose did not change, as demonstrated by 86Rb uptake. The uptake of myo-(3H)inositol was lowered after 20 h of incubation in galactose and remained below that of the control throughout the 5-day exposure period. The coadministration of sorbinil to the galactose medium normalized the myo-(3H)inositol uptake. No significant difference in the rates of passive efflux of myo-(3H)inositol or 86Rb from preloaded galactose-treated and control cultures was observed. Culture-media reversal studies were also carried out to determine whether the galactose-induced dysfunction in myo-inositol uptake could be corrected. BLECs were incubated in galactose for 5 days, then changed to galactose-free physiological medium with and without sorbinil for a 1-day recovery period. myo-Inositol uptake was reduced to 34% of control after 6 days of continuous exposure to galactose. Within 24 h of media reversal, myo-inositol uptake returned to or exceeded control values in BLECs switched to either MEM or MEM with sorbinil.2+ reversible and occurred independently of changes in Na(+)-K(+)-ATPase pumping activity in cultured lens epithelium, indicating that the two parameters are not strictly associated and that the deficit in myo-inositol uptake occurs rapidly during hypergalactosemia.

  17. Effect of myo-inositol and alpha-lipoic acid on oocyte quality in polycystic ovary syndrome non-obese women undergoing in vitro fertilization: a pilot study.

    PubMed

    Rago, R; Marcucci, I; Leto, G; Caponecchia, L; Salacone, P; Bonanni, P; Fiori, C; Sorrenti, G; Sebastianelli, A

    2015-01-01

    The aim of the present study was to evaluate the effectiveness of the combined administration of myo-inositol and α-lipoic acid in polycystic ovary syndrome (PCOS) patients with normal body mass index (BMI), who had previously undergone intracytoplasmic sperm injection (ICSI) and received myo-inositol alone. Thirty-six of 65 normal-weight patients affected by PCOS who did not achieve pregnancy and one patient who had a spontaneous abortion were re-enrolled and given a cycle of treatment with myo-inositol and α-lipoic acid. For all female partners of the treated couples, the endocrine-metabolic and ultrasound parameters, ovarian volume, oocyte and embryo quality, and pregnancy rates were assessed before and after three months of treatment and compared with those of previous in vitro fertilization (IVF) cycle(s). After supplementation of myo-inositol with α-lipoic acid, insulin levels, BMI and ovarian volume were significantly reduced compared with myo-inositol alone. No differences were found in the fertilization and cleavage rate or in the mean number of transferred embryos between the two different treatments, whereas the number of grade 1 embryos was significantly increased, with a significant reduction in the number of grade 2 embryos treated with myo-inositol plus α-lipoic acid. Clinical pregnancy was not significantly different with a trend for a higher percentage for of myo-inositol and α-lipoic acid compared to the myo-inositol alone group. Our preliminary data suggest that the supplementation of myo-inositol and α-lipoic acid in PCOS patients undergoing an IVF cycle can help to improve their reproductive outcome and also their metabolic profiles, opening potential for their use in long-term prevention of PCOS. PMID:26753656

  18. Isolation of 1-monomethylphosphoinositol 4,5-bisphosphate (a product of methanolysis of inositol 1,2-(cyclic)-4,5-trisphosphate) from Swiss mouse 3T3 cells

    SciTech Connect

    Lips, D.L.; Bross, T.E.; Majerus, P.W.

    1988-01-01

    We have noted two previously undescribed inositol polyphosphates in neutral methanol extracts from Swiss mouse 3T3 cells that were grown in (/sup 3/H)inositol and stimulated with platelet-derived growth factor. They have been identified as 1-monomethylphosphoinositol 4,5-bisphosphate and 1-monomethylphosphoinositol 4-phosphate by comparison to a synthesized standard using HPLC chromatography, paper electrophoresis, and enzymatic dephosphorylation with inositol polyphosphate 5-phosphomonoesterase and intestinal alkaline phosphatase. We propose that these compounds are formed by methanolysis of inositol 1,2-(cyclic)-4,5-trisphosphate and inositol 1,2-(cyclic)-4-bisphosphate present in the cells. Inositol cyclic phosphates did not react with neutral methanol in the absence of the cells, which are required for the methanolysis reaction. These findings suggest a role for inositol cyclic phosphates as reactive compounds that are added to as yet unidentified cellular acceptors.

  19. Inositol 1,4,5-trisphosphate-induced calcium release from platelet plasma membrane vesicles

    SciTech Connect

    Rengasamy, A.; Feinberg, H.

    1988-02-15

    A platelet membrane preparation, enriched in plasma membrane markers, took up /sup 45/Ca/sup 2 +/ in exchange for intravesicular Na+ and released it after the addition of inositol 1,4,5-trisphosphate (IP3). The possibility that contaminating dense tubular membrane (DTS) vesicles contributed the Ca/sup 2 +/ released by IP3 was eliminated by the addition of vanadate to inhibit Ca/sup +/-ATPase-mediated DTS Ca/sup 2 +/ sequestration and by the finding that only plasma membrane vesicles exhibit Na/sup +/-dependent Ca/sup 2 +/ uptake. Ca/sup 2 +/ released by IP3 was dependent on low extravesicular Ca/sup 2 +/ concentrations. IP3-induced Ca/sup 2 +/ release was additive to that released by Na/sup +/ addition while GTP or polyethylene glycol (PEG) had no effect. These results strongly suggest that IP3 facilitates extracellular Ca/sup 2 +/ influx in addition to release from DTS membranes.

  20. REGULATION OF CA2+ ENTRY BY INOSITOL LIPIDS IN MAMMALIAN CELLS BY MULTIPLE MECHANISMS

    PubMed Central

    Balla, Tamas

    2009-01-01

    Increased phosphoinositide turnover was first identified as an early signal transduction event initiated by cell surface receptors that were linked to calcium signaling. Subsequently, the generation of inositol 1,4,5-trisphosphate by phosphoinositide-specific phospholipase C enzymes was defined as the major link between inositide turnover and the cytosolic Ca2+ rise in response to external stimulation. However, in the last decades, phosphoinositides have been emerging as major regulatory lipids involved in virtually every membrane-associated signaling process. Phosphoinositides regulate both the activity and the trafficking of almost all ion channels and transporters contributing to the maintenance of the ionic gradients that are essential for the proper functioning of all eukaryotic cells. Here we summarize the various means by which phosphoinositides affect ion channel functions with special emphasis on Ca2+ signaling and outline the principles that govern the highly compartmentalized roles of these regulatory lipids. PMID:19395084