Science.gov

Sample records for activated methyl cycle

  1. Benzoyl-L-arginine methyl ester (BAME)-esterase activity in human plasma during the gravidic-puerperal cycle.

    PubMed

    Salles Meirelles, R

    1977-01-01

    Benzoyl-L-arginine methyl ester (BAME)-esterase activity of plasma was measured in women going through the gravidic-puerperal cycle and compared with plasma of non-pregnant women. Plasma from women in the 36th to 40th week of pregnancy hydrolyzes BAME two times more rapidly than that from non-pregnant women. During pregnancy, BAME-esterase activity in plasma increases progressively up to the 40th week, decreases during labor, and after delivery reaches the same level as in non-pregnant women. The BAME-esterase activity of plasma was affected by the storage temperature, with differences demonstrable between -20 and -4 C and between pregnant and non-pregnant women.

  2. A nickel hydride complex in the active site of methyl-coenzyme m reductase: implications for the catalytic cycle.

    PubMed

    Harmer, Jeffrey; Finazzo, Cinzia; Piskorski, Rafal; Ebner, Sieglinde; Duin, Evert C; Goenrich, Meike; Thauer, Rudolf K; Reiher, Markus; Schweiger, Arthur; Hinderberger, Dariush; Jaun, Bernhard

    2008-08-20

    Methanogenic archaea utilize a specific pathway in their metabolism, converting C1 substrates (i.e., CO2) or acetate to methane and thereby providing energy for the cell. Methyl-coenzyme M reductase (MCR) catalyzes the key step in the process, namely methyl-coenzyme M (CH3-S-CoM) plus coenzyme B (HS-CoB) to methane and CoM-S-S-CoB. The active site of MCR contains the nickel porphinoid F430. We report here on the coordinated ligands of the two paramagnetic MCR red2 states, induced when HS-CoM (a reversible competitive inhibitor) and the second substrate HS-CoB or its analogue CH3-S-CoB are added to the enzyme in the active MCR red1 state (Ni(I)F430). Continuous wave and pulse EPR spectroscopy are used to show that the MCR red2a state exhibits a very large proton hyperfine interaction with principal values A((1)H) = [-43,-42,-5] MHz and thus represents formally a Ni(III)F430 hydride complex formed by oxidative addition to Ni(I). In view of the known ability of nickel hydrides to activate methane, and the growing body of evidence for the involvement of MCR in "reverse" methanogenesis (anaerobic oxidation of methane), we believe that the nickel hydride complex reported here could play a key role in helping to understand both the mechanism of "reverse" and "forward" methanogenesis.

  3. Inhibition of DNA Methylation Alters Chromatin Organization, Nuclear Positioning and Activity of 45S rDNA Loci in Cycling Cells of Q. robur

    PubMed Central

    Horvat, Tomislav; Maglica, Željka; Vojta, Aleksandar; Zoldoš, Vlatka

    2014-01-01

    Around 2200 copies of genes encoding ribosomal RNA (rRNA) in pedunculate oak, Quercus robur, are organized into two rDNA loci, the major (NOR-1) and the minor (NOR-2) locus. We present the first cytogenetic evidence indicating that the NOR-1 represents the active nucleolar organizer responsible for rRNA synthesis, while the NOR-2 probably stays transcriptionally silent and does not participate in the formation of the nucleolus in Q. robur, which is a situation resembling the well-known phenomenon of nucleolar dominance. rDNA chromatin topology analyses in cycling root tip cells by light and electron microscopy revealed the minor locus to be highly condensed and located away from the nucleolus, while the major locus was consistently associated with the nucleolus and often exhibited different levels of condensation. In addition, silver precipitation was confined exclusively to the NOR-1 locus. Also, NOR-2 was highly methylated at cytosines and rDNA chromatin was marked with histone modifications characteristic for repressive state. After treatment of the root cells with the methylation inhibitor 5-aza-2′-deoxycytidine, we observed an increase in the total level of rRNA transcripts and a decrease in DNA methylation level at the NOR-2 locus. Also, NOR-2 sites relocalized with respect to the nuclear periphery/nucleolus, however, the relocation did not affect the contribution of this locus to nucleolar formation, nor did it affect rDNA chromatin decondensation, strongly suggesting that NOR-2 has lost the function of rRNA synthesis and nucleolar organization. PMID:25093501

  4. Myricetin and methyl eugenol combination enhances the anticancer activity, cell cycle arrest and apoptosis induction of cis-platin against HeLa cervical cancer cell lines.

    PubMed

    Yi, Jin-Ling; Shi, Song; Shen, Yan-Li; Wang, Ling; Chen, Hai-Yan; Zhu, Jun; Ding, Yan

    2015-01-01

    Drug combination therapies are common practice in the treatment of cancer. In this study, we evaluated the anticancer effects of myricetin (MYR), methyl eugenol (MEG) and cisplatin (CP) both separately as well as in combination against cervical cancer (HeLa) cells. To demonstrate whether MYR and MEG enhance the anticancer activity of CP against cervical cancer cells, we treated HeLa cells with MYR and MEG alone or in combination with cisplatin and evaluated cell growth and apoptosis using MTT (3 (4, 5 dimethyl thiazol 2yl) 2, 5 diphenyltetrazolium bromide) assay, LDH release assay, flow cytometry and fluorescence microscopy. The results revealed that, as compared to single drug treatment, the combination of MYR or MEG with CP resulted in greater effect in inhibiting cancer cell growth and inducing apoptosis. Cell apoptosis induction, Caspase-3 activity, cell cycle arrest and mitochondrial membrane potential loss were systematically studied to reveal the mechanisms of synergy between MYR, MEG and CP. Combination of MYR or MEG with CP resulted in more potent apoptosis induction as revealed by fluorescence microscopy using Hoechst 33258 and AO-ETBR staining. The combination treatment also increased the number of cells in G0/G1 phase dramatically as compared to single drug treatment. Mitochondrial membrane potential loss (ΛΨm) as well as Caspase-3 activity was much higher in combination treatment as compared to single drug treatment. Findings of this investigation suggest that MYR and MEG combined with cisplatin is a potential clinical chemotherapeutic approach in human cervical cancer.

  5. Myricetin and methyl eugenol combination enhances the anticancer activity, cell cycle arrest and apoptosis induction of cis-platin against HeLa cervical cancer cell lines

    PubMed Central

    Yi, Jin-Ling; Shi, Song; Shen, Yan-Li; Wang, Ling; Chen, Hai-Yan; Zhu, Jun; Ding, Yan

    2015-01-01

    Drug combination therapies are common practice in the treatment of cancer. In this study, we evaluated the anticancer effects of myricetin (MYR), methyl eugenol (MEG) and cisplatin (CP) both separately as well as in combination against cervical cancer (HeLa) cells. To demonstrate whether MYR and MEG enhance the anticancer activity of CP against cervical cancer cells, we treated HeLa cells with MYR and MEG alone or in combination with cisplatin and evaluated cell growth and apoptosis using MTT (3 (4, 5 dimethyl thiazol 2yl) 2, 5 diphenyltetrazolium bromide) assay, LDH release assay, flow cytometry and fluorescence microscopy. The results revealed that, as compared to single drug treatment, the combination of MYR or MEG with CP resulted in greater effect in inhibiting cancer cell growth and inducing apoptosis. Cell apoptosis induction, Caspase-3 activity, cell cycle arrest and mitochondrial membrane potential loss were systematically studied to reveal the mechanisms of synergy between MYR, MEG and CP. Combination of MYR or MEG with CP resulted in more potent apoptosis induction as revealed by fluorescence microscopy using Hoechst 33258 and AO-ETBR staining. The combination treatment also increased the number of cells in G0/G1 phase dramatically as compared to single drug treatment. Mitochondrial membrane potential loss (ΛΨm) as well as Caspase-3 activity was much higher in combination treatment as compared to single drug treatment. Findings of this investigation suggest that MYR and MEG combined with cisplatin is a potential clinical chemotherapeutic approach in human cervical cancer. PMID:25972998

  6. A DNA methylation ratchet governs progression through a bacterial cell cycle

    PubMed Central

    Collier, Justine; McAdams, Harley H.; Shapiro, Lucy

    2007-01-01

    The Caulobacter cell cycle is driven by a cascade of transient regulators, starting with the expression of DnaA in G1 and ending with the expression of the essential CcrM DNA methyltransferase at the completion of DNA replication. The timing of DnaA accumulation was found to be regulated by the methylation state of the dnaA promoter, which in turn depends on the chromosomal position of dnaA near the origin of replication and restriction of CcrM synthesis to the end of the cell cycle. The dnaA gene is preferentially transcribed from a fully methylated promoter. DnaA initiates DNA replication and activates the transcription of the next cell-cycle regulator, GcrA. With the passage of the replication fork, the dnaA promoter becomes hemimethylated, and DnaA accumulation drops. GcrA then activates the transcription of the next cell-cycle regulator, CtrA, once the replication fork passes through the ctrA P1 promoter, generating two hemimethylated copies of ctrA. The ctrA gene is preferentially transcribed from a hemimethylated promoter. CtrA then activates the transcription of ccrM, to bring the newly replicated chromosome to the fully methylated state, promoting dnaA transcription and the start of a new cell cycle. We show that the cell-cycle timing of CcrM is critical for Caulobacter fitness. The sequential changes in the chromosomal methylation state serve to couple the progression of DNA replication to cell-cycle events regulated by the master transcriptional regulatory cascade, thus providing a ratchet mechanism for robust cell-cycle control. PMID:17942674

  7. Activity Cycles in Stars

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    Starspots and stellar activity can be detected in other stars using high precision photometric and spectrometric measurements. These observations have provided some surprises (starspots at the poles - sunspots are rarely seen poleward of 40 degrees) but more importantly they reveal behaviors that constrain our models of solar-stellar magnetic dynamos. The observations reveal variations in cycle characteristics that depend upon the stellar structure, convection zone dynamics, and rotation rate. In general, the more rapidly rotating stars are more active. However, for stars like the Sun, some are found to be inactive while nearly identical stars are found to be very active indicating that periods like the Sun's Maunder Minimum (an inactive period from 1645 to 1715) are characteristic of Sun-like stars.

  8. Cell cycle deregulation by methyl isocyanate: Implications in liver carcinogenesis.

    PubMed

    Panwar, Hariom; Raghuram, Gorantla V; Jain, Deepika; Ahirwar, Alok K; Khan, Saba; Jain, Subodh K; Pathak, Neelam; Banerjee, Smita; Maudar, Kewal K; Mishra, Pradyumna K

    2014-03-01

    Liver is often exposed to plethora of chemical toxins. Owing to its profound physiological role and central function in metabolism and homeostasis, pertinent succession of cell cycle in liver epithelial cells is of prime importance to maintain cellular proliferation. Although recent evidence has displayed a strong association between exposures to methyl isocyanate (MIC), one of the most toxic isocyanates, and neoplastic transformation, molecular characterization of the longitudinal effects of MIC on cell cycle regulation has never been performed. Here, we sequentially delineated the status of different proteins arbitrating the deregulation of cell cycle in liver epithelial cells treated with MIC. Our data reaffirms the oncogenic capability of MIC with elevated DNA damage response proteins pATM and γ-H2AX, deregulation of DNA damage check point genes CHK1 and CHK2, altered expression of p53 and p21 proteins involved in cell cycle arrest with perturbation in GADD-45 expression in the treated cells. Further, alterations in cyclin A, cyclin E, CDK2 levels along with overexpression of mitotic spindle checkpoints proteins Aurora A/B, centrosomal pericentrin protein, chromosomal aberrations, and loss of Pot1a was observed. Thus, MIC impacts key proteins involved in cell cycle regulation to trigger genomic instability as a possible mechanism of developmental basis of liver carcinogenesis.

  9. 13-Methyl-palmatrubine induces apoptosis and cell cycle arrest in A549 cells in vitro and in vivo

    PubMed Central

    Chen, Jingxian; Lu, Xingang; Lu, Chenghua; Wang, Chunying; Xu, Haizhu; Xu, Xiaoli; Gou, Haixin; Zhu, Bing; Du, Wangchun

    2016-01-01

    Corydalis yanhusuo, a well-known herbaceous plant, is commonly used in the treatment of inflammation, injury and pain. One natural agent isolated from Corydalis yanhusuo, 13-methyl-palmatrubine, was found to have a cytotoxic effect on cancer cells as reported in published studies. In the present study, we synthesized a potential anti-lung tumor agent, 13-methyl-palmatrubine and analyzed its activity. 13-Methyl-palmatrubine exhibited a cytotoxic effect on a panel of cancer cell lines in a time- and concentration-dependent manner. Among all the tested cancer cell lines, lung cancer A549 cells were most sensitive to 13-methyl-palmatrubine treatment. Meanwhile 13-methyl-palmatrubine showed less cytotoxicity in human normal cells. Our investigation revealed that 13-methyl-palmatrubine induced apoptosis and cell cycle arrest in A549 cells in a dose-dependent manner. Furthermore, 13-methyl-palmatrubine treatment caused activation of P38 and JNK pathways and blocked the EGFR pathway. In conclusion, our findings demonstrated that 13-methyl-palmatrubine inhibited the growth of A549 cells mediated by blocking of the EGFR signaling pathway and activation of the MAPK signaling pathway and provides a better understanding of the molecular mechanisms of 13-methyl-palmatrubine. PMID:27633656

  10. RB1 Methylation by SMYD2 Enhances Cell Cycle Progression through an Increase of RB1 Phosphorylation12

    PubMed Central

    Cho, Hyun-Soo; Hayami, Shinya; Toyokawa, Gouji; Maejima, Kazuhiro; Yamane, Yuka; Suzuki, Takehiro; Dohmae, Naoshi; Kogure, Masaharu; Kang, Daechun; Neal, David E; Ponder, Bruce AJ; Yamaue, Hiroki; Nakamura, Yusuke; Hamamoto, Ryuji

    2012-01-01

    It is well known that RB functions are regulated by posttranslational modifications such as phosphorylation and acetylation, but the significance of lysine methylation on RB has not been fully elucidated. Our expression analysis of SMYD2 by quantitative real-time polymerase chain reaction showed that expression levels of SMYD2 are significantly elevated in human bladder carcinomas compared with nonneoplastic bladder tissues (P < .0001), and its expression levels in tumor tissues were much higher than those of any other normal tissues. SMYD2 knockdown resulted in the suppression of cancer cell growth, and cell cycle analysis indicated that SMYD2 might play a crucial role in the G1/S transition. According to an in vitro methyltransferase assay, we found that SMYD2 methylates RB1 protein, and liquid chromatography-tandem mass spectrometry analysis revealed lysine 810 of RB1 to be methylated by SMYD2. Importantly, this methylation enhanced Ser 807/811 phosphorylation of RB1 both in vitro and in vivo. Furthermore, we demonstrated that methylated RB1 accelerates E2F transcriptional activity and promotes cell cycle progression. SMYD2 is an important oncoprotein in various types of cancer, and SMYD2-dependent RB1 methylation at lysine 810 promotes cell cycle progression of cancer cells. Further study may explore SMYD2-dependent RB1 methylation as a potential therapeutic target in human cancer. PMID:22787429

  11. The dynamic DNA methylation cycle from egg to sperm in the honey bee Apis mellifera

    PubMed Central

    Drewell, Robert A.; Bush, Eliot C.; Remnant, Emily J.; Wong, Garrett T.; Beeler, Suzannah M.; Stringham, Jessica L.; Lim, Julianne; Oldroyd, Benjamin P.

    2014-01-01

    In honey bees (Apis mellifera), the epigenetic mark of DNA methylation is central to the developmental regulation of caste differentiation, but may also be involved in additional biological functions. In this study, we examine the whole genome methylation profiles of three stages of the haploid honey bee genome: unfertilised eggs, the adult drones that develop from these eggs and the sperm produced by these drones. These methylomes reveal distinct patterns of methylation. Eggs and sperm show 381 genes with significantly different CpG methylation patterns, with the vast majority being more methylated in eggs. Adult drones show greatly reduced levels of methylation across the genome when compared with both gamete samples. This suggests a dynamic cycle of methylation loss and gain through the development of the drone and during spermatogenesis. Although fluxes in methylation during embryogenesis may account for some of the differentially methylated sites, the distinct methylation patterns at some genes suggest parent-specific epigenetic marking in the gametes. Extensive germ line methylation of some genes possibly explains the lower-than-expected frequency of CpG sites in these genes. We discuss the potential developmental and evolutionary implications of methylation in eggs and sperm in this eusocial insect species. PMID:24924193

  12. The dynamic DNA methylation cycle from egg to sperm in the honey bee Apis mellifera.

    PubMed

    Drewell, Robert A; Bush, Eliot C; Remnant, Emily J; Wong, Garrett T; Beeler, Suzannah M; Stringham, Jessica L; Lim, Julianne; Oldroyd, Benjamin P

    2014-07-01

    In honey bees (Apis mellifera), the epigenetic mark of DNA methylation is central to the developmental regulation of caste differentiation, but may also be involved in additional biological functions. In this study, we examine the whole genome methylation profiles of three stages of the haploid honey bee genome: unfertilised eggs, the adult drones that develop from these eggs and the sperm produced by these drones. These methylomes reveal distinct patterns of methylation. Eggs and sperm show 381 genes with significantly different CpG methylation patterns, with the vast majority being more methylated in eggs. Adult drones show greatly reduced levels of methylation across the genome when compared with both gamete samples. This suggests a dynamic cycle of methylation loss and gain through the development of the drone and during spermatogenesis. Although fluxes in methylation during embryogenesis may account for some of the differentially methylated sites, the distinct methylation patterns at some genes suggest parent-specific epigenetic marking in the gametes. Extensive germ line methylation of some genes possibly explains the lower-than-expected frequency of CpG sites in these genes. We discuss the potential developmental and evolutionary implications of methylation in eggs and sperm in this eusocial insect species.

  13. Production and Cycling of Methylated Mercury Species in Arctic Marine Waters

    NASA Astrophysics Data System (ADS)

    Lehnherr, I.; St. Louis, V. L.; Hintelmann, H.

    2009-12-01

    Monomethyl mercury (MMHg), a vertebrate neurotoxin which bioaccumulates through foodwebs, is found in some Arctic marine mammals at levels that may be harmful to northern peoples consuming them as food. Unfortunately, sources of MMHg to polar marine food webs remain unknown, in part due to the complex nature of Hg cycling in polar marine waters. Since 2005, we have been sampling the marine waters of the Canadian Arctic Archipelago from the Canadian Coast Guard research icebreaker CCGS Amundsen. Early results demonstrated that elevated concentrations of both MMHg and dimethyl mercury (DMHg, a toxic, gaseous Hg species) are found in sub-surface Arctic marine waters (89±36 pg L-1 and 73±37 pg L-1, respectively) despite low total Hg (THg) concentrations (290±220 pg L-1), suggesting an internal source of methylated Hg. We tested the hypothesis that methylated Hg species are produced directly in the marine water column using stable-isotope Hg tracers. Seawater samples were amended with 198Hg(II) and incubated for 0, 8, 16 or 24 hours to measure the production of MM198Hg, DM198Hg and gaseous elemental 198Hg(0) (GEM) over time. A second tracer, MM199Hg, was also added to quantify MMHg methylation (formation of DM199Hg), demethylation (loss of MM199Hg) and reduction (formation of 199Hg(0)). Preliminary analysis of the data indicates that Hg(II) is methylated in polar marine waters to form both MMHg (first order rate-constant km1 ~6x10-4 d-1) and DMHg (km2 ~5x10-6 d-1). We also found that DMHg production from MMHg is ~50x faster than with Hg(II) as the substrate. Furthermore, at a small number of sites, we measured methylation rates that were elevated by almost a full order of magnitude compared to the average, suggesting that methylation hotspots may exist in Arctic marine waters. However, during the less productive fall season when the CCGS Amundsen cruises were conducted, demethylation of MMHg generally appears to dominate in the water column and can occur via a number

  14. Combined analysis of DNA methylation and cell cycle in cancer cells.

    PubMed

    Desjobert, Cécile; El Maï, Mounir; Gérard-Hirne, Tom; Guianvarc'h, Dominique; Carrier, Arnaud; Pottier, Cyrielle; Arimondo, Paola B; Riond, Joëlle

    2015-01-01

    DNA methylation is a chemical modification of DNA involved in the regulation of gene expression by controlling the access to the DNA sequence. It is the most stable epigenetic mark and is widely studied for its role in major biological processes. Aberrant DNA methylation is observed in various pathologies, such as cancer. Therefore, there is a great interest in analyzing subtle changes in DNA methylation induced by biological processes or upon drug treatments. Here, we developed an improved methodology based on flow cytometry to measure variations of DNA methylation level in melanoma and leukemia cells. The accuracy of DNA methylation quantification was validated with LC-ESI mass spectrometry analysis. The new protocol was used to detect small variations of cytosine methylation occurring in individual cells during their cell cycle and those induced by the demethylating agent 5-aza-2'-deoxycytidine (5AzadC). Kinetic experiments confirmed that inheritance of DNA methylation occurs efficiently in S phase and revealed a short delay between DNA replication and completion of cytosine methylation. In addition, this study suggests that the uncoupling of 5AzadC effects on DNA demethylation and cell proliferation might be related to the duration of the DNA replication phase.

  15. Anticandidal activity of curcumin and methyl cinnamaldehyde.

    PubMed

    Khan, Neelofar; Shreaz, Sheikh; Bhatia, Rimple; Ahmad, Sheikh Imran; Muralidhar, Sumathi; Manzoor, Nikhat; Khan, Luqman Ahmad

    2012-04-01

    Cinnamaldehyde, its derivatives and curcumin are reported to have strong antifungal activity. In this work we report and compare anticandidal activity of curcumin (CUR) and α-methyl cinnamaldehyde (MCD) against 38 strains of Candida (3; standard, fluconazole sensitive, 24; clinical, fluconazole sensitive, 11; clinical, fluconazole resistant). The minimum inhibitory concentrations (MIC₉₀) of CUR ranged from 250 to 650 μg/ml for sensitive strains and from 250 to 500 μg/ml for resistant strains. MIC₉₀ of MCD varied between 100 and 250 μg/ml and 100-200 μg/ml for sensitive and resistant strains, respectively. Higher activity of MCD as compared to CUR was further reinforced by spot assays and growth curve studies. At their respective MIC₉₀ values, in the presence of glucose, average inhibition of H+-efflux caused by CUR and MCD against standard, clinical and resistant isolates was 24%, 31%, 32% and 54%, 52%, 54%, respectively. Inhibition of H+-extrusion leads to intracellular acidification and cell death, average pHi for control, CUR and MCD exposed cells was 6.68, 6.39 and 6.20, respectively. Scanning electron micrographs of treated cells show more extensive damage in case of MCD. Haemolytic activity of CUR and MCD at their highest MIC was 11.45% and 13.00%, respectively as against 20% shown by fluconazole at typical MIC of 30 μg/ml. In conclusion, this study shows significant anticandidal activity of CUR and MCD against both azole-resistant and sensitive clinical isolates, MCD is found to be more effective.

  16. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process.

    PubMed

    Salminen, Antero; Kauppinen, Anu; Hiltunen, Mikko; Kaarniranta, Kai

    2014-07-01

    Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process.

  17. Reprogramming DNA methylation in the mammalian life cycle: building and breaking epigenetic barriers.

    PubMed

    Seisenberger, Stefanie; Peat, Julian R; Hore, Timothy A; Santos, Fátima; Dean, Wendy; Reik, Wolf

    2013-01-05

    In mammalian development, epigenetic modifications, including DNA methylation patterns, play a crucial role in defining cell fate but also represent epigenetic barriers that restrict developmental potential. At two points in the life cycle, DNA methylation marks are reprogrammed on a global scale, concomitant with restoration of developmental potency. DNA methylation patterns are subsequently re-established with the commitment towards a distinct cell fate. This reprogramming of DNA methylation takes place firstly on fertilization in the zygote, and secondly in primordial germ cells (PGCs), which are the direct progenitors of sperm or oocyte. In each reprogramming window, a unique set of mechanisms regulates DNA methylation erasure and re-establishment. Recent advances have uncovered roles for the TET3 hydroxylase and passive demethylation, together with base excision repair (BER) and the elongator complex, in methylation erasure from the zygote. Deamination by AID, BER and passive demethylation have been implicated in reprogramming in PGCs, but the process in its entirety is still poorly understood. In this review, we discuss the dynamics of DNA methylation reprogramming in PGCs and the zygote, the mechanisms involved and the biological significance of these events. Advances in our understanding of such natural epigenetic reprogramming are beginning to aid enhancement of experimental reprogramming in which the role of potential mechanisms can be investigated in vitro. Conversely, insights into in vitro reprogramming techniques may aid our understanding of epigenetic reprogramming in the germline and supply important clues in reprogramming for therapies in regenerative medicine.

  18. Interplay between Gliotoxin Resistance, Secretion, and the Methyl/Methionine Cycle in Aspergillus fumigatus

    PubMed Central

    Owens, Rebecca A.; O'Keeffe, Grainne; Smith, Elizabeth B.; Dolan, Stephen K.; Hammel, Stephen; Sheridan, Kevin J.; Fitzpatrick, David A.; Keane, Thomas M.

    2015-01-01

    Mechanistic studies on gliotoxin biosynthesis and self-protection in Aspergillus fumigatus, both of which require the gliotoxin oxidoreductase GliT, have revealed a rich landscape of highly novel biochemistries, yet key aspects of this complex molecular architecture remain obscure. Here we show that an A. fumigatus ΔgliA strain is completely deficient in gliotoxin secretion but still retains the ability to efflux bisdethiobis(methylthio)gliotoxin (BmGT). This correlates with a significant increase in sensitivity to exogenous gliotoxin because gliotoxin trapped inside the cell leads to (i) activation of the gli cluster, as disabling gli cluster activation, via gliZ deletion, attenuates the sensitivity of an A. fumigatus ΔgliT strain to gliotoxin, thus implicating cluster activation as a factor in gliotoxin sensitivity, and (ii) increased methylation activity due to excess substrate (dithiol gliotoxin) for the gliotoxin bis-thiomethyltransferase GtmA. Intracellular dithiol gliotoxin is oxidized by GliT and subsequently effluxed by GliA. In the absence of GliA, gliotoxin persists in the cell and is converted to BmGT, with levels significantly higher than those in the wild type. Similarly, in the ΔgliT strain, gliotoxin oxidation is impeded, and methylation occurs unchecked, leading to significant S-adenosylmethionine (SAM) depletion and S-adenosylhomocysteine (SAH) overproduction. This in turn significantly contributes to the observed hypersensitivity of gliT-deficient A. fumigatus to gliotoxin. Our observations reveal a key role for GliT in preventing dysregulation of the methyl/methionine cycle to control intracellular SAM and SAH homeostasis during gliotoxin biosynthesis and exposure. Moreover, we reveal attenuated GliT abundance in the A. fumigatus ΔgliK strain, but not the ΔgliG strain, following exposure to gliotoxin, correlating with relative sensitivities. Overall, we illuminate new systems interactions that have evolved in gliotoxin-producing, compared

  19. Repression of p53 activity by Smyd2-mediated methylation.

    PubMed

    Huang, Jing; Perez-Burgos, Laura; Placek, Brandon J; Sengupta, Roopsha; Richter, Mario; Dorsey, Jean A; Kubicek, Stefan; Opravil, Susanne; Jenuwein, Thomas; Berger, Shelley L

    2006-11-30

    Specific sites of lysine methylation on histones correlate with either activation or repression of transcription. The tumour suppressor p53 (refs 4-7) is one of only a few non-histone proteins known to be regulated by lysine methylation. Here we report a lysine methyltransferase, Smyd2, that methylates a previously unidentified site, Lys 370, in p53. This methylation site, in contrast to the known site Lys 372, is repressing to p53-mediated transcriptional regulation. Smyd2 helps to maintain low concentrations of promoter-associated p53. We show that reducing Smyd2 concentrations by short interfering RNA enhances p53-mediated apoptosis. We find that Set9-mediated methylation of Lys 372 inhibits Smyd2-mediated methylation of Lys 370, providing regulatory cross-talk between post-translational modifications. In addition, we show that the inhibitory effect of Lys 372 methylation on Lys 370 methylation is caused, in part, by blocking the interaction between p53 and Smyd2. Thus, similar to histones, p53 is subject to both activating and repressing lysine methylation. Our results also predict that Smyd2 may function as a putative oncogene by methylating p53 and repressing its tumour suppressive function.

  20. Methyl Jasmonate: Putative Mechanisms of Action on Cancer Cells Cycle, Metabolism, and Apoptosis

    PubMed Central

    Cesari, Italo Mario; Figueiredo Rodrigues, Mariana; Mendonça, Bruna dos Santos; Amôedo, Nivea Dias; Rumjanek, Franklin David

    2014-01-01

    Methyl jasmonate (MJ), an oxylipid that induces defense-related mechanisms in plants, has been shown to be active against cancer cells both in vitro and in vivo, without affecting normal cells. Here we review most of the described MJ activities in an attempt to get an integrated view and better understanding of its multifaceted modes of action. MJ (1) arrests cell cycle, inhibiting cell growth and proliferation, (2) causes cell death through the intrinsic/extrinsic proapoptotic, p53-independent apoptotic, and nonapoptotic (necrosis) pathways, (3) detaches hexokinase from the voltage-dependent anion channel, dissociating glycolytic and mitochondrial functions, decreasing the mitochondrial membrane potential, favoring cytochrome c release and ATP depletion, activating pro-apoptotic, and inactivating antiapoptotic proteins, (4) induces reactive oxygen species mediated responses, (5) stimulates MAPK-stress signaling and redifferentiation in leukemia cells, (6) inhibits overexpressed proinflammatory enzymes in cancer cells such as aldo-keto reductase 1 and 5-lipoxygenase, and (7) inhibits cell migration and shows antiangiogenic and antimetastatic activities. Finally, MJ may act as a chemosensitizer to some chemotherapics helping to overcome drug resistant. The complete lack of toxicity to normal cells and the rapidity by which MJ causes damage to cancer cells turn MJ into a promising anticancer agent that can be used alone or in combination with other agents. PMID:24648844

  1. Serine Metabolism Supports the Methionine Cycle and DNA/RNA Methylation through De Novo ATP Synthesis in Cancer Cells

    PubMed Central

    Maddocks, Oliver D.K.; Labuschagne, Christiaan F.; Adams, Peter D.; Vousden, Karen H.

    2016-01-01

    Summary Crosstalk between cellular metabolism and the epigenome regulates epigenetic and metabolic homeostasis and normal cell behavior. Changes in cancer cell metabolism can directly impact epigenetic regulation and promote transformation. Here we analyzed the contribution of methionine and serine metabolism to methylation of DNA and RNA. Serine can contribute to this pathway by providing one-carbon units to regenerate methionine from homocysteine. While we observed this contribution under methionine-depleted conditions, unexpectedly, we found that serine supported the methionine cycle in the presence and absence of methionine through de novo ATP synthesis. Serine starvation increased the methionine/S-adenosyl methionine ratio, decreasing the transfer of methyl groups to DNA and RNA. While serine starvation dramatically decreased ATP levels, this was accompanied by lower AMP and did not activate AMPK. This work highlights the difference between ATP turnover and new ATP synthesis and defines a vital function of nucleotide synthesis beyond making nucleic acids. PMID:26774282

  2. Environmental analysis of the life cycle emissions of 2-methyl tetrahydrofuran solvent manufactured from renewable resources.

    PubMed

    Slater, C Stewart; Savelski, Mariano J; Hitchcock, David; Cavanagh, Eduardo J

    2016-01-01

    An environmental analysis has been conducted to determine the cradle to gate life cycle emissions to manufacture the green solvent, 2-methyl tetrahydrofuran. The solvent is considered a greener chemical since it can be manufactured from renewable resources with a lower life cycle footprint. Analyses have been performed using different methods to show greenness in both its production and industrial use. This solvent can potentially be substituted for other ether and chlorinated solvents commonly used in organometallic and biphasic reactions steps in pharmaceutical and fine chemical syntheses. The 2-methyl tetrahydrofuran made from renewable agricultural by-products is marketed by Penn A Kem under the name ecoMeTHF™. The starting material, 2-furfuraldehyde (furfural), is produced from corn cob waste by converting the available pentosans by acid hydrolysis. An evaluation of each step in the process was necessary to determine the overall life cycle and specific CO2 emissions for each raw material/intermediate produced. Allocation of credits for CO2 from the incineration of solvents made from renewable feedstocks significantly reduced the overall carbon footprint. Using this approach, the overall life cycle emissions for production of 1 kg of ecoMeTHF™ were determined to be 0.191 kg, including 0.150 kg of CO2. Life cycle emissions generated from raw material manufacture represents the majority of the overall environmental impact. Our evaluation shows that using 2-methyl tetrahydrofuran in an industrial scenario results in a 97% reduction in emissions, when compared to typically used solvents such as tetrahydrofuran, made through a conventional chemical route.

  3. Manipulating and probing the polarisation of a methyl tunnelling system by field-cycling NMR

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Abu-Khumra, Sabah M. M.; Aibout, Abdellah; Horsewill, Anthony J.

    2017-02-01

    In NMR the polarisation of the Zeeman system may be routinely probed and manipulated by applying resonant rf pulses. As with spin-1/2 nuclei, at low temperature the quantum tunnelling states of a methyl rotor are characterised by two energy levels and it is interesting to consider how these tunnelling states might be probed and manipulated in an analogous way to nuclear spins in NMR. In this paper experimental procedures based on magnetic field-cycling NMR are described where, by irradiating methyl tunnelling sidebands, the polarisations of the methyl tunnelling systems are measured and manipulated in a prescribed fashion. At the heart of the technique is a phenomenon that is closely analogous to dynamic nuclear polarisation and the solid effect where forbidden transitions mediate polarisation transfer between 1H Zeeman and methyl tunnelling systems. Depending on the irradiated sideband, both positive and negative polarisations of the tunnelling system are achieved, the latter corresponding to population inversion and negative tunnelling temperatures. The transition mechanics are investigated through a series of experiments and a theoretical model is presented that provides good quantitative agreement.

  4. The Endosymbiont Amoebophilus asiaticus Encodes an S-Adenosylmethionine Carrier That Compensates for Its Missing Methylation Cycle

    PubMed Central

    Haferkamp, Ilka; Penz, Thomas; Geier, Melanie; Ast, Michelle; Mushak, Tanja; Horn, Matthias

    2013-01-01

    All organisms require S-adenosylmethionine (SAM) as a methyl group donor and cofactor for various biologically important processes. However, certain obligate intracellular parasitic bacteria and also the amoeba symbiont Amoebophilus asiaticus have lost the capacity to synthesize this cofactor and hence rely on its uptake from host cells. Genome analyses revealed that A. asiaticus encodes a putative SAM transporter. The corresponding protein was functionally characterized in Escherichia coli: import studies demonstrated that it is specific for SAM and S-adenosylhomocysteine (SAH), the end product of methylation. SAM transport activity was shown to be highly dependent on the presence of a membrane potential, and by targeted analyses, we obtained direct evidence for a proton-driven SAM/SAH antiport mechanism. Sequence analyses suggest that SAM carriers from Rickettsiales might operate in a similar way, in contrast to chlamydial SAM transporters. SAM/SAH antiport is of high physiological importance, as it allows for compensation for the missing methylation cycle. The identification of a SAM transporter in A. asiaticus belonging to the Bacteroidetes phylum demonstrates that SAM transport is more widely spread than previously assumed and occurs in bacteria belonging to three different phyla (Proteobacteria, Chlamydiae, and Bacteroidetes). PMID:23667233

  5. The Hydrologic Cycle Distributed Active Archive Center

    NASA Technical Reports Server (NTRS)

    Hardin, Danny M.; Goodman, H. Michael

    1995-01-01

    The Marshall Space Flight Center Distributed Active Archive Center in Huntsville, Alabama supports the acquisition, production, archival and dissemination of data relevant to the study of the global hydrologic cycle. This paper describes the Hydrologic Cycle DAAC, surveys its principle data holdings, addresses future growth, and gives information for accessing the data sets.

  6. Brain feminization requires active repression of masculinization via DNA methylation

    PubMed Central

    Nugent, Bridget M.; Wright, Christopher L.; Shetty, Amol C.; Hodes, Georgia E.; Lenz, Kathryn M.; Mahurkar, Anup; Russo, Scott J.; Devine, Scott E.; McCarthy, Margaret M.

    2015-01-01

    The developing mammalian brain is destined for a female phenotype unless exposed to gonadal hormones during a perinatal sensitive period. It has been assumed that the undifferentiated brain is masculinized by direct induction of transcription by ligand-activated nuclear steroid receptors. We found that a primary effect of gonadal steroids in the highly sexually-dimorphic preoptic area (POA) is to reduce activity of DNA methyltransferase (Dnmt) enzymes, thereby decreasing DNA methylation and releasing masculinizing genes from epigenetic repression. Pharmacological inhibition of Dnmts mimicked gonadal steroids, resulting in masculinized neuronal markers and male sexual behavior in females. Conditional knockout of the de novo Dnmt isoform, Dnmt3a, also masculinized sexual behavior in female mice. RNA sequencing revealed gene and isoform variants modulated by methylation that may underlie the divergent reproductive behaviors of males versus females. Our data show that brain feminization is maintained by the active suppression of masculinization via DNA methylation. PMID:25821913

  7. ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED ARSENICALS

    EPA Science Inventory

    ACTIVATION OF AP-1 IN UROTSA CELLS BY METHYLATED TRIVALENT ARSENICALS. Z Drobna1, I Jaspers2, D J Thomas3 and M Styblo1. 1Department of Pediatrics; 2Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill, NC, USA; 3US EPA, RTP, NC, USA.

  8. Global water cycle and solar activity variations

    NASA Astrophysics Data System (ADS)

    Al-Tameemi, Muthanna A.; Chukin, Vladimir V.

    2016-05-01

    The water cycle is the most active and most important component in the circulation of global mass and energy in the Earth system. Furthermore, water cycle parameters such as evaporation, precipitation, and precipitable water vapour play a major role in global climate change. In this work, we attempt to determine the impact of solar activity on the global water cycle by analyzing the global monthly values of precipitable water vapour, precipitation, and the Solar Modulation Potential in 1983-2008. The first object of this study was to calculate global evaporation for the period 1983-2008. For this purpose, we determined the water cycle rate from satellite data, and precipitation/evaporation relationship from 10 years of Planet Simulator model data. The second object of our study was to investigate the relationship between the Solar Modulation Potential (solar activity index) and the evaporation for the period 1983-2008. The results showed that there is a relationship between the solar modulation potential and the evaporation values for the period of study. Therefore, we can assume that the solar activity has an impact on the global water cycle.

  9. Comparison of the anti-herpes simplex virus activities of propolis and 3-methyl-but-2-enyl caffeate.

    PubMed

    Amoros, M; Lurton, E; Boustie, J; Girre, L; Sauvager, F; Cormier, M

    1994-05-01

    The in vitro activity against herpes simplex virus type 1 of 3-methyl-but-2-enyl caffeate isolated from poplar buds or prepared by synthesis was investigated. Under conditions of one or multiple multiplication cycles, this compound, which is a minor constituent of propolis, was found to reduce the viral titer by 3 log10, and viral DNA synthesis by 32-fold.

  10. Solar activity cycle - History and predictions

    SciTech Connect

    Withbroe, G.L. )

    1989-12-01

    The solar output of short-wavelength radiation, solar wind, and energetic particles depends strongly on the solar cycle. These energy outputs from the sun control conditions in the interplanetary medium and in the terrestrial magnetosphere and upper atmosphere. Consequently, there is substantial interest in the behavior of the solar cycle and its effects. This review briefly discusses historical data on the solar cycle and methods for predicting its further behavior, particularly for the current cycle, which shows signs that it will have moderate to exceptionally high levels of activity. During the next few years, the solar flux of short-wavelength radiation and particles will be more intense than normal, and spacecraft in low earth orbit will reenter earlier than usual. 46 refs.

  11. Development of a global ocean mercury model with a methylation cycle: Outstanding issues

    NASA Astrophysics Data System (ADS)

    Semeniuk, Kirill; Dastoor, Ashu

    2017-02-01

    We present a newly developed global ocean mercury (Hg) transport and biogeochemistry model and use preanthropogenic equilibrium simulations to highlight physical and chemical processes which reveal significant knowledge gaps that need to be addressed. As with previous 3-D ocean Hg model work we use a bulk chemistry scheme based on particulate organic carbon remineralization. We also include an explicit methylation cycle based on available reaction rates. The methylation to demethylation rate ratio based on various field studies is found to be inconsistent with the concentration ratios measured in the Southern Ocean around Antarctica and in the Arctic. There is also model-measurement disagreement in the old waters of the tropical and North Pacific Ocean. The model produces an intermediate water maximum in total Hg in this region reflecting the higher age of water which is absent in observations. The model also underestimates total Hg concentrations in the deepest waters in this region. These disagreements in depth profile shape point to an inadequate representation of scavenging and sedimentation and possibly seabed emission or remobilization of Hg. In addition, the total Hg distribution differences compared to previous model work reflect sensitivity to ocean model transport characteristics and in particular the tracer diffusion. The residence time of Hg in the global ocean and the surface evasion flux of elemental Hg is sensitive to such model aspects. We find a global ocean Hg turnover time against sediment burial to be about 1100 years which is within the range of previous studies.

  12. Lysine methylation represses p53 activity in teratocarcinoma cancer cells

    PubMed Central

    Zhu, Jiajun; Dou, Zhixun; Sammons, Morgan A.; Levine, Arnold J.; Berger, Shelley L.

    2016-01-01

    TP53 (which encodes the p53 protein) is the most frequently mutated gene among all human cancers, whereas tumors that retain the wild-type TP53 gene often use alternative mechanisms to repress the p53 tumor-suppressive function. Testicular teratocarcinoma cells rarely contain mutations in TP53, yet the transcriptional activity of wild-type p53 is compromised, despite its high expression level. Here we report that in the teratocarcinoma cell line NTera2, p53 is subject to lysine methylation at its carboxyl terminus, which has been shown to repress p53’s transcriptional activity. We show that reduction of the cognate methyltransferases reactivates p53 and promotes differentiation of the NTera2 cells. Furthermore, reconstitution of methylation-deficient p53 mutants into p53-depleted NTera2 cells results in elevated expression of p53 downstream targets and precocious loss of pluripotent gene expression compared with re-expression of wild-type p53. Our results provide evidence that lysine methylation of endogenous wild-type p53 represses its activity in cancer cells and suggest new therapeutic possibilities of targeting testicular teratocarcinoma. PMID:27535933

  13. POSSIBLE CHROMOSPHERIC ACTIVITY CYCLES IN AD LEO

    SciTech Connect

    Buccino, Andrea P.; Petrucci, Romina; Mauas, Pablo J. D.; Jofré, Emiliano

    2014-01-20

    AD Leo (GJ 388) is an active dM3 flare star that has been extensively observed both in the quiescent and flaring states. Since this active star is near the fully convective boundary, studying its long-term chromospheric activity in detail could be an appreciable contribution to dynamo theory. Here, using the Lomb-Scargle periodogram, we analyze the Ca II K line-core fluxes derived from CASLEO spectra obtained between 2001 and 2013 and the V magnitude from the ASAS database between 2004 and 2010. From both of these totally independent time series, we obtain a possible activity cycle with a period of approximately seven years and a less significant shorter cycle of approximately two years. A tentative interpretation is that a dynamo operating near the surface could be generating the longer cycle, while a second dynamo operating in the deep convection zone could be responsible for the shorter one. Based on the long duration of our observing program at CASLEO and the fact that we observe different spectral features simultaneously, we also analyze the relation between simultaneous measurements of the Na I index (R{sub D}{sup ′}), Hα, and Ca II K fluxes at different activity levels of AD Leo, including flares.

  14. Mapping methyl jasmonate-mediated transcriptional reprogramming of metabolism and cell cycle progression in cultured Arabidopsis cells

    PubMed Central

    Pauwels, Laurens; Morreel, Kris; De Witte, Emilie; Lammertyn, Freya; Van Montagu, Marc; Boerjan, Wout; Inzé, Dirk; Goossens, Alain

    2008-01-01

    Jasmonates (JAs) are plant-specific signaling molecules that steer a diverse set of physiological and developmental processes. Pathogen attack and wounding inflicted by herbivores induce the biosynthesis of these hormones, triggering defense responses both locally and systemically. We report on alterations in the transcriptome of a fast-dividing cell culture of the model plant Arabidopsis thaliana after exogenous application of methyl JA (MeJA). Early MeJA response genes encoded the JA biosynthesis pathway proteins and key regulators of MeJA responses, including most JA ZIM domain proteins and MYC2, together with transcriptional regulators with potential, but yet unknown, functions in MeJA signaling. In a second transcriptional wave, MeJA reprogrammed cellular metabolism and cell cycle progression. Up-regulation of the monolignol biosynthesis gene set resulted in an increased production of monolignols and oligolignols, the building blocks of lignin. Simultaneously, MeJA repressed activation of M-phase genes, arresting the cell cycle in G2. MeJA-responsive transcription factors were screened for their involvement in early signaling events, in particular the regulation of JA biosynthesis. Parallel screens based on yeast one-hybrid and transient transactivation assays identified both positive (MYC2 and the AP2/ERF factor ORA47) and negative (the C2H2 Zn finger proteins STZ/ZAT10 and AZF2) regulators, revealing a complex control of the JA autoregulatory loop and possibly other MeJA-mediated downstream processes. PMID:18216250

  15. Insertional inactivation of the methionine s-methyltransferase gene eliminates the s-methylmethionine cycle and increases the methylation ratio.

    PubMed

    Kocsis, Michael G; Ranocha, Philippe; Gage, Douglas A; Simon, Eric S; Rhodes, David; Peel, Gregory J; Mellema, Stefan; Saito, Kazuki; Awazuhara, Motoko; Li, Changjiang; Meeley, Robert B; Tarczynski, Mitchell C; Wagner, Conrad; Hanson, Andrew D

    2003-04-01

    Methionine (Met) S-methyltransferase (MMT) catalyzes the synthesis of S-methyl-Met (SMM) from Met and S-adenosyl-Met (Ado-Met). SMM can be reconverted to Met by donating a methyl group to homocysteine (homo-Cys), and concurrent operation of this reaction and that mediated by MMT sets up the SMM cycle. SMM has been hypothesized to be essential as a methyl donor or as a transport form of sulfur, and the SMM cycle has been hypothesized to guard against depletion of the free Met pool by excess Ado-Met synthesis or to regulate Ado-Met level and hence the Ado-Met to S-adenosylhomo-Cys ratio (the methylation ratio). To test these hypotheses, we isolated insertional mmt mutants of Arabidopsis and maize (Zea mays). Both mutants lacked the capacity to produce SMM and thus had no SMM cycle. They nevertheless grew and reproduced normally, and the seeds of the Arabidopsis mutant had normal sulfur contents. These findings rule out an indispensable role for SMM as a methyl donor or in sulfur transport. The Arabidopsis mutant had significantly higher Ado-Met and lower S-adenosylhomo-Cys levels than the wild type and consequently had a higher methylation ratio (13.8 versus 9.5). Free Met and thiol pools were unaltered in this mutant, although there were moderate decreases (of 30%-60%) in free serine, threonine, proline, and other amino acids. These data indicate that the SMM cycle contributes to regulation of Ado-Met levels rather than preventing depletion of free Met.

  16. Menadione- (2-methyl-1,4-naphthoquinone-) dependent enzymatic redox cycling and calcium release by mitochondria.

    PubMed

    Frei, B; Winterhalter, K H; Richter, C

    1986-07-29

    The results presented in this paper reveal the existence of three distinct menadione (2-methyl-1,4-naphthoquinone) reductases in mitochondria: NAD(P)H:(quinone-acceptor) oxidoreductase (D,T-diaphorase), NADPH:(quinone-acceptor) oxidoreductase, and NADH:(quinone-acceptor) oxidoreductase. All three enzymes reduce menadione in a two-electron step directly to the hydroquinone form. NADH-ubiquinone oxidoreductase (NADH dehydrogenase) and NAD(P)H azoreductase do not participate significantly in menadione reduction. In mitochondrial extracts, the menadione-induced NAD(P)H oxidation occurs beyond stoichiometric reduction of the quinone and is accompanied by O2 consumption. Benzoquinone is reduced more rapidly than menadione but does not undergo redox cycling. In intact mitochondria, menadione triggers oxidation of intramitochondrial pyridine nucleotides, cyanide-insensitive O2 consumption, and a transient decrease of delta psi. In the presence of intramitochondrial Ca2+, the menadione-induced oxidation of pyridine nucleotides is accompanied by their hydrolysis, and Ca2+ is released from mitochondria. The menadione-induced Ca2+ release leaves mitochondria intact, provided excessive Ca2+ cycling is prevented. In both selenium-deficient and selenium-adequate mitochondria, menadione is equally effective in inducing oxidation of pyridine nucleotides and Ca2+ release. Thus, menadione-induced Ca2+ release is mediated predominantly by enzymatic two-electron reduction of menadione, and not by H2O2 generated by menadione-dependent redox cycling. Our findings argue against D,T-diaphorase being a control device that prevents quinone-dependent oxygen toxicity in mitochondria.

  17. Activation energy of methyl radical decay in methane hydrate.

    PubMed

    Takeya, Kei; Nango, Kouhei; Sugahara, Takeshi; Ohgaki, Kazunari; Tani, Atsushi

    2005-11-10

    The thermal stability of gamma-ray-induced methyl radicals in methane hydrate was studied using the ESR method at atmospheric pressure and 210-260 K. The methyl radical decay proceeded with the second-order reaction, and ethane molecules were generated from the dimerization process. The methyl radical decay proceeds by two different temperature-dependent processes, that is, the respective activation energies of these processes are 20.0 +/- 1.6 kJ/mol for the lower temperature region of 210-230 K and 54.8 +/- 5.7 kJ/mol for the higher temperature region of 235-260 K. The former agrees well with the enthalpy change of methane hydrate dissociation into ice and gaseous methane, while the latter agrees well with the enthalpy change into liquid water and gaseous methane. The present findings reveal that methane hydrates dissociate into liquid (supercooled) water and gaseous methane in the temperature range of 235-260 K.

  18. Development of solar activity in 24th cycle: scenario of 15th cycle?

    NASA Astrophysics Data System (ADS)

    Lozytsky, V.; Efimenko, V.

    2012-12-01

    For more precise definition of prognosis of 24th cycle, the peculiarities of growth of solar activity was studied in previous 23 cycles. The interest was focused on a phase of sharp increasing of activity, beginning from 20th month of cycles. The sufficiently close correlation was found between smoothed Wolf's number in the cycle maximum Wmax and increment of sunspot's number on phase of activity increasing. From this analysis follows that for 24th cycle the following parameters are expected: Wmax = 105±11, аnd time of maximum - middle 2013. If this prognosis will be come true, the 24th cycle will be similar to cycle No. 15.

  19. Stochastic cycle selection in active flow networks

    PubMed Central

    Woodhouse, Francis G.; Forrow, Aden; Fawcett, Joanna B.; Dunkel, Jörn

    2016-01-01

    Active biological flow networks pervade nature and span a wide range of scales, from arterial blood vessels and bronchial mucus transport in humans to bacterial flow through porous media or plasmodial shuttle streaming in slime molds. Despite their ubiquity, little is known about the self-organization principles that govern flow statistics in such nonequilibrium networks. Here we connect concepts from lattice field theory, graph theory, and transition rate theory to understand how topology controls dynamics in a generic model for actively driven flow on a network. Our combined theoretical and numerical analysis identifies symmetry-based rules that make it possible to classify and predict the selection statistics of complex flow cycles from the network topology. The conceptual framework developed here is applicable to a broad class of biological and nonbiological far-from-equilibrium networks, including actively controlled information flows, and establishes a correspondence between active flow networks and generalized ice-type models. PMID:27382186

  20. Stochastic cycle selection in active flow networks

    NASA Astrophysics Data System (ADS)

    Woodhouse, Francis; Forrow, Aden; Fawcett, Joanna; Dunkel, Jorn

    2016-11-01

    Active biological flow networks pervade nature and span a wide range of scales, from arterial blood vessels and bronchial mucus transport in humans to bacterial flow through porous media or plasmodial shuttle streaming in slime molds. Despite their ubiquity, little is known about the self-organization principles that govern flow statistics in such non-equilibrium networks. By connecting concepts from lattice field theory, graph theory and transition rate theory, we show how topology controls dynamics in a generic model for actively driven flow on a network. Through theoretical and numerical analysis we identify symmetry-based rules to classify and predict the selection statistics of complex flow cycles from the network topology. Our conceptual framework is applicable to a broad class of biological and non-biological far-from-equilibrium networks, including actively controlled information flows, and establishes a new correspondence between active flow networks and generalized ice-type models.

  1. Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells.

    PubMed

    Lee, Kyung-Mi; Yun, Ji Ho; Lee, Dong Hwa; Park, Young Gyun; Son, Kun Ho; Nho, Chu Won; Kim, Yeong Shik

    2015-04-17

    We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers.

  2. Role of a redox-based methylation switch in mRNA life cycle (pre- and post-transcriptional maturation) and protein turnover: implications in neurological disorders.

    PubMed

    Trivedi, Malav S; Deth, Richard C

    2012-01-01

    Homeostatic synaptic scaling in response to neuronal stimulus or activation, and due to changes in cellular niche, is an important phenomenon for memory consolidation, retrieval, and other similar cognitive functions (Turrigiano and Nelson, 2004). Neurological disorders and cognitive disabilities in autism, Rett syndrome, schizophrenia, dementia, etc., are strongly correlated to alterations in protein expression (both synaptic and cytoplasmic; Cajigas et al., 2010). This correlation suggests that efficient temporal regulation of synaptic protein expression is important for synaptic plasticity. In addition, equilibrium between mRNA processing, protein translation, and protein turnover is a critical sensor/trigger for recording synaptic information, normal cognition, and behavior (Cajigas et al., 2010). Thus a regulatory switch, which controls the lifespan, maturation, and processing of mRNA, might influence cognition and adaptive behavior. Here, we propose a two part novel hypothesis that methylation might act as this suggested coordinating switch to critically regulate mRNA maturation at (1) the pre-transcription level, by regulating precursor-RNA processing into mRNA, via other non-coding RNAs and their influence on splicing phenomenon, and (2) the post-transcription level by modulating the regulatory functions of ribonucleoproteins and RNA binding proteins in mRNA translation, dendritic translocation as well as protein synthesis and synaptic turnover. DNA methylation changes are well recognized and highly correlated to gene expression levels as well as, learning and memory; however, RNA methylation changes are recently characterized and yet their functional implications are not established. This review article provides some insight on the intriguing consequences of changes in methylation levels on mRNA life-cycle. We also suggest that, since methylation is under the control of glutathione anti-oxidant levels (Lertratanangkoon et al., 1997), the redox status of

  3. Linking ATM Promoter Methylation to Cell Cycle Protein Expression in Brain Tumor Patients: Cellular Molecular Triangle Correlation in ATM Territory.

    PubMed

    Mehdipour, P; Karami, F; Javan, Firouzeh; Mehrazin, M

    2015-08-01

    tumor grade (p = 0.01). Given the important role of cell cycle checkpoint proteins as well as RB and ATM in TL and cancer evolution, further assessment is warranted to shed more light on the pathway linking the telomere instability to tumor progression. High ATM methylation rate in brain tumor patients could open a new avenue toward early screening and cancer therapy.

  4. Coronal Activity and Extended Solar Cycles

    NASA Astrophysics Data System (ADS)

    Altrock, R. C.

    2012-12-01

    Wilson et al. (1988, Nature 333, 748) discussed a number of solar parameters, which appear at high latitudes and gradually migrate towards the equator, merging with the sunspot "butterfly diagram". They found that this concept had been identified by earlier investigators extending back to 1957. They named this process the "Extended Solar Cycle" (ESC). Altrock (1997, Solar Phys. 170, 411) found that this process continued in Fe XIV 530.3 nm emission features. In cycles 21 - 23 solar maximum occurred when the number of Fe XIV emission regions per day > 0.19 (averaged over 365 days and both hemispheres) first reached latitudes 18°, 21° and 21°, for an average of 20° ± 1.7°. Other recent studies have shown that Torsional Oscillation (TO) negative-shear zones are co-located with the ESC from at least 50° down to the equator and also in the zones where the Rush to the Poles occur. These phenomena indicate that coronal activity occurring up to 50° and higher latitudes is related to TO shear zones, another indicator that the ESC is an important solar process. Another high-latitude process, which appears to be connected with the ESC, is the "Rush to the Poles" ("Rush") of polar crown prominences and their associated coronal emission, including Fe XIV. The Rush is is a harbinger of solar maximum (cf. Altrock, 2003, Solar Phys. 216, 343). Solar maximum in cycles 21 - 23 occurred when the center line of the Rush reached a critical latitude. These latitudes were 76°, 74° and 78°, respectively, for an average of 76° ± 2°. Applying the above conclusions to Cycle 24 is difficult due to the unusual nature of this cycle. Cycle 24 displays an intermittent "Rush" that is only well-defined in the northern hemisphere. In 2009 an initial slope of 4.6°/yr was found in the north, compared to an average of 9.4 ± 1.7 °/yr in the previous three cycles. This early fit to the Rush would have reached 76° at 2014.6. However, in 2010 the slope increased to 7.5°/yr (an increase

  5. RNA-directed DNA methylation induces transcriptional activation in plants

    PubMed Central

    Shibuya, Kenichi; Fukushima, Setsuko; Takatsuji, Hiroshi

    2009-01-01

    A class-C floral homeotic gene of Petunia, pMADS3, is specifically expressed in the stamen and carpels of developing flowers. We had previously reported the ect-pMADS3 phenomenon in which introduction of a part of the pMADS3 genomic sequence, including intron 2, induces ectopic expression of endogenous pMADS3. Unlike transcriptional or posttranscriptional gene silencing triggered by the introduction of homologous sequences, this observation is unique in that the gene expression is up-regulated. In this study, we demonstrated that the ect-pMADS3 phenomenon is due to transcriptional activation based on RNA-directed DNA methylation (RdDM) occurring in a particular CG in a putative cis-element in pMADS3 intron 2. The CG methylation was maintained over generations, along with pMADS3 ectopic expression, even in the absence of RNA triggers. These results demonstrate a previously undescribed transcriptional regulatory mechanism that could lead to the generation of a transcriptionally active epiallele, thereby contributing to plant evolution. Our results also reveal a putative negative cis-element for organ-specific transcriptional regulation of class-C floral homeotic genes, which could be difficult to identify by other approaches. PMID:19164525

  6. Evaluation of larvicidal activity and ecotoxicity of linalool, methyl cinnamate and methyl cinnamate/linalool in combination against Aedes aegypti.

    PubMed

    Fujiwara, Gislene M; Annies, Vinícius; de Oliveira, Camila F; Lara, Ricardo A; Gabriel, Maria M; Betim, Fernando C M; Nadal, Jéssica M; Farago, Paulo V; Dias, Josiane F G; Miguel, Obdulio G; Miguel, Marilis D; Marques, Francisco A; Zanin, Sandra M W

    2017-05-01

    The frequent use of synthetic pesticides to control Aedes aegypti population can lead to environmental and/or human contamination and the emergence of resistant insects. Linalool and methyl cinnamate are presented as an alternative to the synthetic pesticides, since they can exhibit larvicidal, repellent and/or insecticidal activity and are considered safe for use. The aim of this study was to evaluate the larvicidal activity of methyl cinnamate, linalool and methyl cinnamate/linalool in combination (MC-L) (1:4 ratio, respectively) against Aedes aegypti. The in vitro preliminary toxicity through brine shrimp lethality assay and hemolytic activity, and the phytotoxic potential were also investigated to assess the safety of their use as larvicide. Methyl cinnamate showed significant larvicidal activity when compared to linalool (LC50 values of 35.4µg/mL and 275.2µg/mL, respectively) and to MC-L (LC50 138.0µg/mL). Larvae morphological changes subjected to the specified treatments were observed, as the flooding of tracheal system and midgut damage, hindering the larval development and survival. Preliminary in vitro toxicity through brine shrimp showed the high bioactivity of the substances (methyl cinnamate LC50 35.5µg/mL; linalool LC50 96.1µg/mL) and the mixture (MC-L LC50 57.7µg/mL). The results showed that, despite the higher larvicidal activity of methyl cinnamate, the use of MC-L as a larvicide seems to be more appropriate due to its significant larvicidal activity and low toxicity.

  7. Human T lymphocytes express N-methyl-D-aspartate receptors functionally active in controlling T cell activation

    SciTech Connect

    Miglio, Gianluca; Varsaldi, Federica; Lombardi, Grazia . E-mail: lombardi@pharm.unipmn.it

    2005-12-30

    The aim of this study was to investigate the expression and the functional role of N-methyl-D-aspartate (NMDA) receptors in human T cells. RT-PCR analysis showed that human resting peripheral blood lymphocytes (PBL) and Jurkat T cells express genes encoding for both NR1 and NR2B subunits: phytohemagglutinin (PHA)-activated PBL also expresses both these genes and the NR2A and NR2D genes. Cytofluorimetric analysis showed that NR1 expression increases as a consequence of PHA (10 {mu}g/ml) treatment. D-(-)-2-Amino-5-phosphonopentanoic acid (D-AP5), and (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine [(+)-MK 801], competitive and non-competitive NMDA receptor antagonists, respectively, inhibited PHA-induced T cell proliferation, whereas they did not affect IL-2 (10 U/ml)-induced proliferation of PHA blasts. These effects were due to the prevention of T cell activation (inhibition of cell aggregate formation and CD25 expression), but not to cell cycle arrest or death. These results demonstrate that human T lymphocytes express NMDA receptors, which are functionally active in controlling cell activation.

  8. Evaluation of alternariol and alternariol methyl ether for mutagenic activity in Salmonella typhimurium

    SciTech Connect

    Davis, V.M.; Stack, M.E. )

    1994-10-01

    Alternariol and alternariol methyl ether were tested in the Ames Salmonella typhimurium assay, and both were shown, with and without metabolic activation, to be nonmutagenic to strains TA98 and TA100. The finding of other investigators that alternariol methyl ether is weakly mutagenic to Ta98 without metabolic activation could have resulted from the presence of a small amount of one of the highly mutagenic altertoxins in the alternariol methyl ether originally tested. 9 refs., 3 figs., 1 tab.

  9. Chikusetsusaponin IVa methyl ester induces cell cycle arrest by the inhibition of nuclear translocation of β-catenin in HCT116 cells

    SciTech Connect

    Lee, Kyung-Mi; Yun, Ji Ho; Lee, Dong Hwa; Park, Young Gyun; Son, Kun Ho; Nho, Chu Won; Kim, Yeong Shik

    2015-04-17

    We demonstrate that chikusetsusaponin IVa methyl ester (CME), a triterpenoid saponin from the root of Achyranthes japonica, has an anticancer activity. We investigate its molecular mechanism in depth in HCT116 cells. CME reduces the amount of β-catenin in nucleus and inhibits the binding of β-catenin to specific DNA sequences (TCF binding elements, TBE) in target gene promoters. Thus, CME appears to decrease the expression of cell cycle regulatory proteins such as Cyclin D1, as a representative target for β-catenin, as well as CDK2 and CDK4. As a result of the decrease of the cell cycle regulatory proteins, CME inhibits cell proliferation by arresting the cell cycle at the G0/G1 phase. Therefore, we suggest that CME as a novel Wnt/β-catenin inhibitor can be a putative agent for the treatment of colorectal cancers. - Highlights: • CME inhibits cell proliferation in HCT116 cells. • CME increases cell cycle arrest at G0/G1 phase and apoptosis. • CME attenuates cyclin D1 and regulates cell cycle regulatory proteins. • CME inhibits β-catenin translocation to nucleus.

  10. Formation and emission of volatile polonium compound by microbial activity and polonium methylation with methylcobalamin.

    PubMed

    Momoshima, N; Song, L X; Osaki, S; Maeda, Y

    2001-07-15

    We observed biologically mediated emission of Po from culture solution inoculated sea sediment extract and incubated under natural light/dark cycle condition or dark condition the emitted Po compound would be lipophilic because of effective collection in organic solvent. Sterilization of the culture medium with antibiotics or CuSO4 completely suppressed growth of microorganisms and resulted in no emission of Po, indicating biological activity of microorganisms is responsible for formation and emission of volatile Po compound. Po emission also occurred when seawater was used as a culture medium. Our finding indicates a possibility of biotic source for atmospheric Po in the environment, which has been believed to be originated from abiotic sources. We compared emission behavior of Po and S in the culture experiments, the elements belong to XVI group in the Periodical Table, and consider that their emission mechanisms involved would be different though the emission of both elements is supported by biological activity of microorganisms. One of the chemical forms of S emitted was confirmed to be dimethyl sulfide (DMS) but that of Po is not known. Methylation experiments of Po with methylcobalamin demonstrated a formation and emission of volatile Po compound. The methylation of Po with methylcobalamin might be related to the observed Po emission in the culture experiments.

  11. Glucuronoyl esterases are active on polymeric substrate, methyl esterified glucuronoxylan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alkali extracted beechwood glucuronoxylan methyl ester prepared by esterification of 4-O-methyl-D-glucuronic acid side residues by methanol was found to serve as substrate of microbial glucuronoyl esterases from Ruminococcus flavefaciens, Schizophyllum commune and Trichoderma reesei. The enzymatic d...

  12. Hemi-methylated DNA regulates DNA methylation inheritance through allosteric activation of H3 ubiquitylation by UHRF1

    PubMed Central

    Harrison, Joseph S; Cornett, Evan M; Goldfarb, Dennis; DaRosa, Paul A; Li, Zimeng M; Yan, Feng; Dickson, Bradley M; Guo, Angela H; Cantu, Daniel V; Kaustov, Lilia; Brown, Peter J; Arrowsmith, Cheryl H; Erie, Dorothy A; Major, Michael B; Klevit, Rachel E; Krajewski, Krzysztof; Kuhlman, Brian; Strahl, Brian D; Rothbart, Scott B

    2016-01-01

    The epigenetic inheritance of DNA methylation requires UHRF1, a histone- and DNA-binding RING E3 ubiquitin ligase that recruits DNMT1 to sites of newly replicated DNA through ubiquitylation of histone H3. UHRF1 binds DNA with selectivity towards hemi-methylated CpGs (HeDNA); however, the contribution of HeDNA sensing to UHRF1 function remains elusive. Here, we reveal that the interaction of UHRF1 with HeDNA is required for DNA methylation but is dispensable for chromatin interaction, which is governed by reciprocal positive cooperativity between the UHRF1 histone- and DNA-binding domains. HeDNA recognition activates UHRF1 ubiquitylation towards multiple lysines on the H3 tail adjacent to the UHRF1 histone-binding site. Collectively, our studies are the first demonstrations of a DNA-protein interaction and an epigenetic modification directly regulating E3 ubiquitin ligase activity. They also define an orchestrated epigenetic control mechanism involving modifications both to histones and DNA that facilitate UHRF1 chromatin targeting, H3 ubiquitylation, and DNA methylation inheritance. DOI: http://dx.doi.org/10.7554/eLife.17101.001 PMID:27595565

  13. Meridional Flow Variations in Cycles 23 and 24: Active Latitude Control of Sunspot Cycle Amplitudes

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Upton, Lisa

    2013-01-01

    We have measured the meridional motions of magnetic elements observed in the photosphere over sunspot cycles 23 and 24 using magnetograms from SOHO/MDI and SDO/HMI. Our measurements confirm the finding of Komm, Howard, and Harvey (1993) that the poleward meridional flow weakens at cycle maxima. Our high spatial and temporal resolution analyses show that this variation is in the form of a superimposed inflow toward the active latitudes. This inflow is weaker in cycle 24 when compared to the inflow in 23, the stronger cycle. This systematic modulation of the meridional flow can modulate the amplitude of the following sunspot cycle through its influence on the Sun's polar fields.

  14. On the role of steric clashes in methylation control of restriction endonuclease activity

    PubMed Central

    Mierzejewska, Karolina; Bochtler, Matthias; Czapinska, Honorata

    2016-01-01

    Restriction-modification systems digest non-methylated invading DNA, while protecting host DNA against the endonuclease activity by methylation. It is widely believed that the methylated DNA would not ‘fit’ into the binding site of the endonuclease in the productive orientation, and thus steric clashes should account for most of the protection. We test this concept statistically by grafting methyl groups in silico onto non-methylated DNA in co-crystal structures with restriction endonucleases. Clash scores are significantly higher for protective than non-protective methylation (P < 0.05% according to the Wilcoxon rank sum test). Structural data alone are sufficient to distinguish between protective and non-protective DNA methylation with 90% confidence and decision thresholds of 1.1 Å and 48 Å3 for the most severe distance-based and cumulative volume-based clash with the protein, respectively (0.1 Å was deducted from each interatomic distance to allow for coordinate errors). The most severe clashes are more pronounced for protective methyl groups attached to the nitrogen atoms (N6-methyladenines and N4-methylcytosines) than for C5-methyl groups on cytosines. Cumulative clashes are comparable for all three types of protective methylation. PMID:26635397

  15. DNA methylation regulates phenotype-dependent transcriptional activity in Candida albicans

    PubMed Central

    Mishra, Prashant K.; Baum, Mary; Carbon, John

    2011-01-01

    DNA methylation is a common epigenetic signaling mechanism associated with silencing of repeated DNA and transcriptional regulation in eukaryotes. Here we report that DNA methylation in the human fungal pathogen Candida albicans is primarily localized within structural genes and modulates transcriptional activity. Major repeat sequences and multigene families are largely free of DNA methylation. Among the genes subject to DNA methylation are those associated with dimorphic transition between yeast and hyphal forms, switching between white and opaque cells, and iron metabolism. Transcriptionally repressed methylated loci showed increased frequency of C-to-T transitions during asexual growth, an evolutionarily stable pattern of repression associated mutation that could bring about genetic alterations under changing environmental or host conditions. Dynamic differential DNA methylation of structural genes may be one factor contributing to morphological plasticity that is cued by nutrition and host interaction. PMID:21730141

  16. Solid phase microextraction for active or passive sampling of methyl bromide during fumigations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The high diffusivity and volatility of methyl bromide make it an ideal compound for Solid Phase Micro Extraction (SPME)-based sampling of air prior to gas-chromatographic quantifications. SPME fibers can be used as active methyl bromide samplers, with high capacities and an equilibrium time of 1-2 m...

  17. [Griseochelin methyl ester, a new polyether derivative with antiviral activity].

    PubMed

    Tonew, E; Tonew, M; Graefe, U; Zöpel, P

    1988-10-01

    The methylester of griseochelin (1) is a new chemically-made antiviral derivate of the antibiotic griseochelin isolated from fermentations of Streptomyces griseus. It belongs to the polyether group and possesses antiviral activity against enveloped RNA and DNA viruses cultivated in chicken embryo cells (CEC), namely influenzavirus A/WSN, vesicularstomatitis virus (Indiana), vaccinia virus (Lister) and herpes simplex hominis virus type 1 (Kupka). The methylester of griseochelin failed to show virucidal effects on extracellular influenza vacciniavirus particles or to influence virus adsorption and penetration processes. The antibiotic in concentrations of 125-15 micrograms/ml inhibited the virus-induced cytopathic effect of the above mentioned viruses and caused over 90 per cent plaque reduction. Addition of 1 during a one-step growth cycle of influenzavirus A at 4 and 6 h p.i. resulted in complete suppression of virus multiplication at the control niveau of the virus yield accumulated to the same time point. A partial reversibility of the antiviral action against influenzavirus A could be achieved. Coxsackie A9 virus growth in human fibroblast cells was not affected by the inhibitor. Electron-optical observations showed a failure of the formation of the viral capside proteins of HSV type 1 at the second halftime of the replication cycle in CEC-infected and 1-treated cultures.

  18. O-Methylated Metabolite of 7,8-Dihydroxyflavone Activates TrkB Receptor and Displays Antidepressant Activity

    PubMed Central

    Liu, Xia; Qi, Qi; Xiao, Ge; Li, Jingyu; Luo, Hongbo R.; Ye, Keqiang

    2016-01-01

    7,8-Dihydroxyflavone (7,8-DHF) acts as a TrkB receptor-specific agonist. It mimics the physiological actions of brain-derived neurotrophic factor (BDNF) and demonstrates remarkable therapeutic efficacy in animal models of various neurological diseases. Nonetheless, its in vivo pharmacokinetic profiles and metabolism remain unclear. Here we report that 7,8-DHF and its O-methylated metabolites distribute in mouse brain after oral administration. Both hydroxy groups can be mono-methylated, and the mono-methylated metabolites activate TrkB in vitro and in vivo. Blocking methylation, using COMT inhibitors, diminishes the agonistic effect of TrkB activation by 7,8-DHF or 4′-dimethylamino-7,8-DHF, supporting the contribution of the methylated metabolite to TrkB activation in mouse brain. Moreover, we have synthesized several methylated metabolite derivatives, and they also potently activate the TrkB receptor and reduce immobility in both forced swim test and tail suspension test, indicating that these methylated metabolites may possess antidepressant activity. Hence, our data demonstrate that 7,8-DHF is orally bioavailable and can penetrate the brain-blood barrier. The O-methylated metabolites are implicated in TrkB receptor activation in the brain. PMID:23445871

  19. Rest-Activity Cycles in Childhood and Adolescent Depression.

    ERIC Educational Resources Information Center

    Armitage, Roseanne; Hoffmann, Robert; Emslie, Graham; Rintelman, Jeanne; Moore, Jarrette; Lewis, Kelly

    2004-01-01

    Objective: To quantify circadian rhythms in rest-activity cycles in depressed children and adolescents. Method: Restactivity cycles were evaluated by actigraphy over five consecutive 24-hour periods in 100 children and adolescents, including 59 outpatients with major depressive disorder (MDD) and 41 healthy normal controls. Total activity, total…

  20. A methylation-stimulated DNA machine: an autonomous isothermal route to methyltransferase activity and inhibition analysis.

    PubMed

    Zhu, Changfeng; Wen, Yanqin; Peng, Hongzhen; Long, Yitao; He, Yao; Huang, Qing; Li, Di; Fan, Chunhai

    2011-04-01

    The operation of DNA nanomachines is generally triggered by either conformational changes of DNA nanostructure or external environmental stimuli. In the present study, we demonstrate an alternative driving force, DNA methylation, to stimulate DNA machine operation. DNA methylation changes neither DNA sequence and conformation nor external environment, however, blocks its cleavage by corresponding methylation-sensitive restriction endonuclease. We thus designed a strand displacement amplification DNA machine, which could be stimulated upon DNA methylation and then autonomously generates accumulated amounts of peroxidase-mimicking DNAzyme signaling machine products in an isothermal manner. The machine product DNAzyme could catalyze the H(2)O(2)-mediated oxidation of 2,2'-azino-bis(3-ethylbenzo thiazoline-6-sulfonic acid) (ABTS(2-)) to a colored product ABTS(·-). This methylation-stimulated DNA machine was further used as a colorimetric assay for analysis of methyltransferases activities and screening of methylation inhibitors. As compared with classical methylation assay, this facile isothermal DNA machine avoids the introduction of methylation-specific polymerase chain reaction and radioactive labels, which might be employed as an effective tool for DNA methylation analysis.

  1. N-Methyl-D-Aspartate Receptor Activation May Contribute to Glufosinate Neurotoxicity

    EPA Science Inventory

    N-Methyl-D-aspartate Receptor Activation May Contribute to Glufosinate Neurotoxicity Glufosinate (GLF) at high levels in mammals causes convulsions through a mechanism that is not completely understood. The structural similarity of GLF to glutamate (GLU) implicates the glutamate...

  2. Alteration of membrane phospholipid methylation by adenosine analogs does not affect T lymphocyte activation

    SciTech Connect

    Gormand, F.; Pacheco, Y. ); Fonlupt, P. ); Revillard, J.P. )

    1990-01-01

    Membrane phospholipid methylation has been described during activation of various immune cells. Moreover recent data indicated modulation of immune cells functions by adenosine. As S-adenosyl-methionine and S-adenosyl-homocysteine are adenosine analogs and modulators of transmethylation reactions, the effects of SAH and SAM were investigated on membrane phospholipid methylation and lymphocyte activation. SAM was shown to induce the membrane phospholipid methylation as assessed by the {sup 3}Hmethyl-incorporation in membrane extract. This effect was inhibited by SAH. In contrast SAM and SAH did not affect the phytohemagglutinin-induced proliferative response of peripheral blood mononuclear cells. SAH neither modified the early internalization of membrane CD3 antigens nor did it prevent the late expression of HLA-DR antigens on lymphocytes activated by phytohemagglutinin. These results indicate that in vitro alteration of phospholipid methylation does not affect subsequent steps of human T lymphocyte activation and proliferation.

  3. Forecasting the Peak of the Present Solar Activity Cycle

    NASA Astrophysics Data System (ADS)

    Hamid, Rabab; Marzouk, Beshir

    2016-07-01

    Solar forecasting of the level of sun Activity is very important subject for all space programs. Most predictions are based on the physical conditions prevailing at or before the solar cycle minimum preceding the maximum in question. Our aim is to predict the maximum peak of cycle 24 using precursor techniques in particular those using spotless event, geomagnetic aa min. index and solar flux F10.7. Also prediction of exact date of the maximum (Tr) is taken in consideration. A study of variation over previous spotless event for cycles 7-23 and that for even cycles (8-22) are carried out for the prediction. Linear correlation between RM and spotless event around the preceding minimum gives RM24t = 101.9with rise time Tr = 4.5 Y. For the even cycles RM24e = 108.3 with rise time Tr = 3.9 Y. Based on the average aa min. index for the year of sunspot minimum cycles (13 - 23), we estimate the expected amplitude for cycle 24 to be RMaa = 116.5 for both the total and even cycles. Application of the data of solar flux F10.7 which cover only cycles (19-23) was taken in consideration and gives predicted maximum amplitude R24 10.7 = 146, which are over estimation. Our result indicating a somewhat weaker cycle 24 as compared to cycles 21-23.

  4. Synthesis of a high specific activity methyl sulfone tritium isotopologue of fevipiprant (NVP-QAW039).

    PubMed

    Luu, Van T; Goujon, Jean-Yves; Meisterhans, Christian; Frommherz, Matthias; Bauer, Carsten

    2015-05-15

    The synthesis of a triple tritiated isotopologue of the CRTh2 antagonist NVP-QAW039 (fevipiprant) with a specific activity >3 TBq/mmol is described. Key to the high specific activity is the methylation of a bench-stable dimeric disulfide precursor that is in situ reduced to the corresponding thiol monomer and methylated with [(3)H3]MeONos having per se a high specific activity. The high specific activity of the tritiated active pharmaceutical ingredient obtained by a build-up approach is discussed in the light of the specific activity usually to be expected if hydrogen tritium exchange methods were applied.

  5. The connection between stellar activity cycles and magnetic field topology

    NASA Astrophysics Data System (ADS)

    See, V.; Jardine, M.; Vidotto, A. A.; Donati, J.-F.; Boro Saikia, S.; Bouvier, J.; Fares, R.; Folsom, C. P.; Gregory, S. G.; Hussain, G.; Jeffers, S. V.; Marsden, S. C.; Morin, J.; Moutou, C.; do Nascimento, J. D.; Petit, P.; Waite, I. A.

    2016-11-01

    Zeeman-Doppler imaging (ZDI) has successfully mapped the large-scale magnetic fields of stars over a large range of spectral types, rotation periods and ages. When observed over multiple epochs, some stars show polarity reversals in their global magnetic fields. On the Sun, polarity reversals are a feature of its activity cycle. In this paper, we examine the magnetic properties of stars with existing chromospherically determined cycle periods. Previous authors have suggested that cycle periods lie on multiple branches, either in the cycle period-Rossby number plane or the cycle period-rotation period plane. We find some evidence that stars along the active branch show significant average toroidal fields that exhibit large temporal variations while stars exclusively on the inactive branch remain dominantly poloidal throughout their entire cycle. This lends credence to the idea that different shear layers are in operation along each branch. There is also evidence that the short magnetic polarity switches observed on some stars are characteristic of the inactive branch while the longer chromospherically determined periods are characteristic of the active branch. This may explain the discrepancy between the magnetic and chromospheric cycle periods found on some stars. These results represent a first attempt at linking global magnetic field properties obtained from ZDI and activity cycles.

  6. A solar cycle timing predictor - The latitude of active regions

    NASA Technical Reports Server (NTRS)

    Schatten, Kenneth H.

    1990-01-01

    A 'Spoerer butterfly' method is used to examine solar cycle 22. It is shown from the latitude of active regions that the cycle can now be expected to peak near November 1989 + or - 8 months, basically near the latter half of 1989.

  7. Meridional Flow Variations in Cycles 23 and 24: Active Latitude Control of Sunspot Cycle Amplitudes

    NASA Astrophysics Data System (ADS)

    Hathaway, David H.; Upton, L.

    2013-07-01

    We have measured the meridional motions of magnetic elements observed in the photosphere over sunspot cycles 23 and 24 using magnetograms from SOHO/MDI and SDO/HMI. Our measurements confirm the finding of Komm, Howard, and Harvey (1993) that the poleward meridional flow weakens at cycle maxima. Our high spatial and temporal resolution analyses show that this variation is in the form of a superimposed inflow toward the active latitudes. This inflow is weaker in cycle 24 when compared to the inflow in 23, the stronger cycle. This systematic modulation of the meridional flow should also modulate the amplitude of the following sunspot cycle through its influence on the Sun’s polar fields. The observational evidence and the theoretical consequences (similar to those of Cameron and Schussler (2012)) will be described. Komm, Howard, and Harvey (1993) Solar Phys. 147, 207. Cameron and Schussler (2012) Astron. Astrophys. 548, A57.

  8. Meridional Flow Variations in Cycles 23 and 24: Active Latitude Control of Sunspot Cycle Amplitudes

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.; Upton, Lisa

    2013-01-01

    We have measured the meridional motions of magnetic elements observed in the photosphere over sunspot cycles 23 and 24 using magnetograms from SOHO/MDI and SDO/HMI. Our measurements confirm the finding of Komm, Howard, and Harvey (1993) that the poleward meridional flow weakens at cycle maxima. Our high spatial and temporal resolution analyses show that this variation is in the form of a superimposed inflow toward the active latitudes. This inflow is weaker in cycle 24 when compared to the inflow in 23, the stronger cycle. This systematic modulation of the meridional flow should also modulate the amplitude of the following sunspot cycle through its influence on the Sun's polar fields. The observational evidence and the theoretical consequences (similar to those of Cameron and Schussler (2012)) will be described.

  9. Statistical pecularities of 24th cycle of solar activity

    NASA Astrophysics Data System (ADS)

    Efimenko, V.; Lozitsky, V.

    2016-06-01

    Current 24th cycle of solar activity is anomalous if following aspects: 1) it had non-monotonous phase of grown, and on different times of this phase it demonstrated peculiarities of both middle and weak cycle, 2) peak of cycle was two-top, and second top was higher than first on about 15 units of averages Wolf's number (in old classification) that is maximum value for all previous cycles, and 3) temporal interval between first and second maximums of cycle was 26 months that is second value from all 24 cycles. As to index of integral distribution of sunspot diameters, it was found earlier that this index α, in the average, equals about 6.0 for 7 previous cycles, in diameter range 50–90 Mm. New statistical analysis based on data for 2010–2015 allows to conclude that for 24th cycle α ≈ 5.8. Thus, dispersion of diameters of sunspots in 24th cycle is typical for majority of solar cycles.

  10. Active Repression of Methylated Genes by the Chromosomal Protein MBD1

    PubMed Central

    Ng, Huck-Hui; Jeppesen, Peter; Bird, Adrian

    2000-01-01

    MBD1 belongs to a family of mammalian proteins that share a methyl-CpG binding domain. Previous work has shown that MBD1 binds to methylated sites in vivo and in vitro and can repress transcription from methylated templates in transcription extracts and in cultured cells. In the present study we established by several experimental criteria that, contrary to a previous report, MBD1 is not a component of the MeCP1 repressor complex. We identified a powerful transcriptional repression domain (TRD) at the C terminus of MBD1 that can actively repress transcription at a distance. Methylation-dependent repression in vivo depends on the presence of both the TRD and the methyl-CpG binding domain. The mechanism is likely to involve deacetylation, since the deacetylase inhibitor trichostatin A can overcome MBD1-mediated repression. Accordingly, we found that endogenous MBD1 is particularly concentrated at sites of centromeric heterochromatin, where acetylated histone H4 is deficient. Unlike MBD2 and MeCP2, MBD1 is not depleted by antibodies to the histone deacetylase HDAC1. Thus, the deacetylase-dependent pathway by which MBD1 actively silences methylated genes is likely to be different from that utilized by the methylation-dependent repressors MeCP1 and MeCP2. PMID:10648624

  11. Active Suppression Of Vibrations In Stirling-Cycle Coolers

    NASA Technical Reports Server (NTRS)

    Johnson, Bruce G.; Flynn, Frederick J.; Gaffney, Monique S.

    1995-01-01

    Report presents results of early research directed toward development of active control systems for suppression of vibrations in spacecraft Stirling-cycle cryocoolers. Researchers developed dynamical models of cryocooler compressor.

  12. BDNF Methylation and Maternal Brain Activity in a Violence-Related Sample

    PubMed Central

    Moser, Dominik A.; Paoloni-Giacobino, Ariane; Stenz, Ludwig; Adouan, Wafae; Manini, Aurélia; Suardi, Francesca; Cordero, Maria I.; Vital, Marylene; Sancho Rossignol, Ana; Rusconi-Serpa, Sandra; Ansermet, François; Dayer, Alexandre G.; Schechter, Daniel S.

    2015-01-01

    It is known that increased circulating glucocorticoids in the wake of excessive, chronic, repetitive stress increases anxiety and impairs Brain-Derived Neurotrophic Factor (BDNF) signaling. Recent studies of BDNF gene methylation in relation to maternal care have linked high BDNF methylation levels in the blood of adults to lower quality of received maternal care measured via self-report. Yet the specific mechanisms by which these phenomena occur remain to be established. The present study examines the link between methylation of the BDNF gene promoter region and patterns of neural activity that are associated with maternal response to stressful versus non-stressful child stimuli within a sample that includes mothers with interpersonal violence-related PTSD (IPV-PTSD). 46 mothers underwent fMRI. The contrast of neural activity when watching children—including their own—was then correlated to BDNF methylation. Consistent with the existing literature, the present study found that maternal BDNF methylation was associated with higher levels of maternal anxiety and greater childhood exposure to domestic violence. fMRI results showed a positive correlation of BDNF methylation with maternal brain activity in the anterior cingulate (ACC), and ventromedial prefrontal cortex (vmPFC), regions generally credited with a regulatory function toward brain areas that are generating emotions. Furthermore we found a negative correlation of BDNF methylation with the activity of the right hippocampus. Since our stimuli focus on stressful parenting conditions, these data suggest that the correlation between vmPFC/ACC activity and BDNF methylation may be linked to mothers who are at a disadvantage with respect to emotion regulation when facing stressful parenting situations. Overall, this study provides evidence that epigenetic signatures of stress-related genes can be linked to functional brain regions regulating parenting stress, thus advancing our understanding of mothers at risk

  13. BEAF regulates cell-cycle genes through the controlled deposition of H3K9 methylation marks into its conserved dual-core binding sites.

    PubMed

    Emberly, Eldon; Blattes, Roxane; Schuettengruber, Bernd; Hennion, Magali; Jiang, Nan; Hart, Craig M; Käs, Emmanuel; Cuvier, Olivier

    2008-12-23

    Chromatin insulators/boundary elements share the ability to insulate a transgene from its chromosomal context by blocking promiscuous enhancer-promoter interactions and heterochromatin spreading. Several insulating factors target different DNA consensus sequences, defining distinct subfamilies of insulators. Whether each of these families and factors might possess unique cellular functions is of particular interest. Here, we combined chromatin immunoprecipitations and computational approaches to break down the binding signature of the Drosophila boundary element-associated factor (BEAF) subfamily. We identify a dual-core BEAF binding signature at 1,720 sites genome-wide, defined by five to six BEAF binding motifs bracketing 200 bp AT-rich nuclease-resistant spacers. Dual-cores are tightly linked to hundreds of genes highly enriched in cell-cycle and chromosome organization/segregation annotations. siRNA depletion of BEAF from cells leads to cell-cycle and chromosome segregation defects. Quantitative RT-PCR analyses in BEAF-depleted cells show that BEAF controls the expression of dual core-associated genes, including key cell-cycle and chromosome segregation regulators. beaf mutants that impair its insulating function by preventing proper interactions of BEAF complexes with the dual-cores produce similar effects in embryos. Chromatin immunoprecipitations show that BEAF regulates transcriptional activity by restricting the deposition of methylated histone H3K9 marks in dual-cores. Our results reveal a novel role for BEAF chromatin dual-cores in regulating a distinct set of genes involved in chromosome organization/segregation and the cell cycle.

  14. Developmentally Programmed 3′ CpG Island Methylation Confers Tissue- and Cell-Type-Specific Transcriptional Activation

    PubMed Central

    Yu, Da-Hai; Ware, Carol; Waterland, Robert A.; Zhang, Jiexin; Chen, Miao-Hsueh; Gadkari, Manasi; Kunde-Ramamoorthy, Govindarajan; Nosavanh, Lagina M.

    2013-01-01

    During development, a small but significant number of CpG islands (CGIs) become methylated. The timing of developmentally programmed CGI methylation and associated mechanisms of transcriptional regulation during cellular differentiation, however, remain poorly characterized. Here, we used genome-wide DNA methylation microarrays to identify epigenetic changes during human embryonic stem cell (hESC) differentiation. We discovered a group of CGIs associated with developmental genes that gain methylation after hESCs differentiate. Conversely, erasure of methylation was observed at the identified CGIs during subsequent reprogramming to induced pluripotent stem cells (iPSCs), further supporting a functional role for the CGI methylation. Both global gene expression profiling and quantitative reverse transcription-PCR (RT-PCR) validation indicated opposing effects of CGI methylation in transcriptional regulation during differentiation, with promoter CGI methylation repressing and 3′ CGI methylation activating transcription. By studying diverse human tissues and mouse models, we further confirmed that developmentally programmed 3′ CGI methylation confers tissue- and cell-type-specific gene activation in vivo. Importantly, luciferase reporter assays provided evidence that 3′ CGI methylation regulates transcriptional activation via a CTCF-dependent enhancer-blocking mechanism. These findings expand the classic view of mammalian CGI methylation as a mechanism for transcriptional silencing and indicate a functional role for 3′ CGI methylation in developmental gene regulation. PMID:23459939

  15. [DNA methylation and epigenetics].

    PubMed

    Vaniushin, B F

    2006-09-01

    In eukaryotic cells, nuclear DNA is subject to enzymatic methylation with the formation of 5-methylcytosine residues, mostly within the CG and CNG sequences. In plants and animals this DNA methylation is species-, tissue-, and organelle-specific. It changes (decreases) with age and is regulated by hormones. On the other hand, genome methylation can control hormonal signal. Replicative and post-replicative DNA methylation types are distinguished. They are mediated by multiple DNA methyltransferases with different site-specificity. Replication is accompanied by the appearance of hemimethylated DNA sites. Pronounced asymmetry of the DNA strand methylation disappears to the end of the cell cycle. A model of methylation-regulated DNA replication is proposed. DNA methylation controls all genetic processes in the cell (replication, transcription, DNA repair, recombination, and gene transposition). It is the mechanism of cell differentiation, gene discrimination and silencing. In animals, suppression of DNA methylation stops development (embryogenesis), switches on apoptosis, and is usually lethal. Disruption of DNA methylation pattern results in the malignant cell transformation and serves as one of the early diagnostic features of carcinogenesis. In malignant cell the pattern of DNA methylation, as well as the set of DNA methyltransferase activities, differs from that in normal cell. In plants inhibition of DNA methylation is accompanied by the induction of seed storage and florescence genes. In eukaryotes one and the same gene can be simultaneously methylated both at cytosine and adenine residues. It can be thus suggested, that the plant cell contains at least two different, and probably, interdependent systems of DNA methylation. The first eukaryotic adenine DNA methyltransferase was isolated from plants. This enzyme methylates DNA with the formation of N6-methyladenine residues in the sequence TGATCA (TGATCA-->TGm6ATCA). Plants possess AdoMet-dependent endonucleases

  16. Development of Solar Activity Cycle 24: Some Comments

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    Our forecast for the development phase of the solar cycle 23 turned out to be right on the mark; one of the very few to have acquired this status out of nearly 40 forecasts made for cycle 23. This is the first time in the 400 year history of the sunspot observations that a forecast was made for a solar cycle, it was defended against a severe peer criticism and came out true. We review the details of our actual forcast and how they fared as the events unfolded during cycle 23. We then consider the present status of the solar wind, the geomagnetic planetary indices, and the recovery of the galactic cosmic rays from cycle 23 modulation. Next, we draw inferences as to what to expect for the development phase of solar cycle 24. We are aware that several forecasts have already been made for the development of solar cycle 24 activity. They cover all possible scenarios, ranging from the most active to the quietest ever cycle. Clearly, some of these forecasts are unlikely to materialize. We discuss emerging details of the physical link between the observations and the workings of the solar dynamo.

  17. Poly(ADP-ribosylation) regulates chromatin organization through histone H3 modification and DNA methylation of the first cell cycle of mouse embryos

    SciTech Connect

    Osada, Tomoharu; Rydén, Anna-Margareta; Masutani, Mitsuko

    2013-04-26

    Highlights: •Histone modification of the mouse pronuclei is regulated by poly(ADP-ribosylation). •Hypermethylation of the mouse female pronuclei is maintained by poly(ADP-ribosylation). •Parp1 is physically interacted with Suz12, which may function in the pronuclei. •Poly(ADP-ribosylation) affects ultrastructure of chromatin of the mouse pronucleus. -- Abstract: We examined the roles of poly(ADP-ribosylation) in chromatin remodeling during the first cell cycle of mouse embryos. Drug-based inhibition of poly(ADP-ribosylation) by a PARP inhibitor, PJ-34, revealed up-regulation of dimethylation of histone H3 at lysine 4 in male pronuclei and down-regulation of dimethylation of histone H3 at lysine 9 (H3K9) and lysine 27 (H3K27). Association of poly(ADP-ribosylation) with histone modification was suggested to be supported by the interaction of Suz12, a histone methyltransferase in the polycomb complex, with Parp1. PARP activity was suggested to be required for a proper localization and maintenance of Suz12 on chromosomes. Notably, DNA methylation level of female pronuclei in one-cell embryos was robustly decreased by PJ-34. Electron microscopic analysis showed a frequent appearance of unusual electron-dense areas within the female pronuclei, implying the disorganized and hypercondensed chromatin ultrastructure. These results show that poly(ADP-ribosylation) is important for the integrity of non-equivalent epigenetic dynamics of pronuclei during the first cell cycle of mouse embryos.

  18. Methyl-CpG-Binding Protein MeCP2 Represses Sp1-Activated Transcription of the Human Leukosialin Gene When the Promoter Is Methylated

    PubMed Central

    Kudo, Shinichi

    1998-01-01

    Human leukosialin (CD43) is expressed in a cell lineage-specific as well as a differentiation stage-specific fashion. The leukosialin promoter, made up of an Sp1 binding site and a sequence similar to that of an initiator, possesses high transcriptional potential. Previous data have demonstrated that the leukosialin gene is down-regulated in nonproducing cells by DNA methylation. In this paper the repressive mechanism of DNA methylation in expression systems is reported. In vitro DNA methylation with SssI (CpG) methylase of leukosialin-chloramphenicol acetyltransferase (CAT) constructs drastically reduced transcriptional activities in stable transfection systems with the human HeLa and Jurkat cell lines. On the other hand, the transcriptional repression by in vitro methylation was less pronounced in Drosophila melanogaster cells, which lack genomic methylation. In these cells, Sp1 could transactivate equally well both the unmethylated and methylated leukosialin promoter. In order to test whether one of the methyl-CpG-binding proteins, MeCP2, is responsible for transcriptional repression of the leukosialin gene, I isolated the human MeCP2 cDNA (encoding 486 amino acid residues) and expressed it in Drosophila cells. I found that MeCP2 substantially inhibited Sp1-activated transcription when the leukosialin promoter was methylated. The level of repression was directly proportional to the amount of MeCP2 expression vector transfected. Analysis of C-terminal deletion mutants of MeCP2 showed that repressive activity of Sp1 transactivation is localized to the N-terminal region consisting of amino acid residues 1 to 193, which encompass the methyl-binding domain. These results suggest that interference with Sp1 transactivation by MeCP2 is an important factor in the down-regulation of leukosialin gene expression by DNA methylation. PMID:9710633

  19. Differential effect of methyl-, butyl- and propylparaben and 17β-estradiol on selected cell cycle and apoptosis gene and protein expression in MCF-7 breast cancer cells and MCF-10A non-malignant cells.

    PubMed

    Wróbel, Anna Maria; Gregoraszczuk, Ewa Łucja

    2014-09-01

    Parabens are alkyl esters of p-hydroxybenzoic acid used widely as antimicrobial preservatives in consumer products, including pharmaceuticals, foods and cosmetics. We showed previously that methyl-, butyl- and propylparaben parabens, even at low doses, stimulate the proliferation of MCF-7 breast cancer cells and non-transformed MCF-10A breast epithelial cells. The present study was undertaken to determine whether this represents a direct effect on cell cycle and apoptotic gene expression. MCF-7 and MCF-10A cells were exposed to methyl, butyl- and propylparaben (20 nm) or 17β-estradiol (10 nm). Cell cycle and apoptotic gene expression were evaluated by real-time polymerase chain reaction and protein expression by Western blot. 17β-estradiol upregulated G1 /S phase genes and downregulated cell cycle progression inhibitors in both MCF-7 and MCF-10A. Upregulation of Bcl-xL and downregulation of caspase 9 was observed in MCF-7, while upregulation of Bcl-xL, BCL2L2 and caspase 9 was noted in MCF-10A. Cyclins in MCF-7 cells were not affected by any of the parabens. Methyl- and butylparaben had no effect on the expression of selected apoptotic genes in MCF-7. In MCF-10A, all parabens tested increased the expression of G1 /S phase genes, and downregulated cell cycle inhibitors. Methylparaben increased pro-survival gene. Butylparaben increased BCL2L1 gene, as did 17β-estradiol, while propylparaben upregulated both the extrinsic and intrinsic apoptotic pathways. There are differences in cell cycle and apoptosis gene expression between parabens and 17β-estradiol in MCF-7 cells. In MCF-10A cells, most of the genes activated by parabens were comparable to those activated by 17β-estradiol.

  20. Effect of Regulatory Element DNA Methylation on Tissue-Type Plasminogen Activator Gene Expression

    PubMed Central

    Rivier-Cordey, Anne-Sophie; Caetano, Carlos; Fish, Richard J.; Kruithof, Egbert K. O.

    2016-01-01

    Expression of the tissue-type plasminogen activator gene (t-PA; gene name PLAT) is regulated, in part, by epigenetic mechanisms. We investigated the relationship between PLAT methylation and PLAT expression in five primary human cell types and six transformed cell lines. CpG methylation was analyzed in the proximal PLAT gene promoter and near the multihormone responsive enhancer (MHRE) -7.3 kilobase pairs upstream of the PLAT transcriptional start site (TSS, -7.3 kb). In Bowes melanoma cells, the PLAT promoter and the MHRE were fully unmethylated and t-PA secretion was extremely high. In other cell types the region from -647 to -366 was fully methylated, whereas an unmethylated stretch of DNA from -121 to +94 was required but not sufficient for detectable t-PA mRNA and t-PA secretion. DNA methylation near the MHRE was not correlated with t-PA secretion. Specific methylation of the PLAT promoter region -151 to +151, inserted into a firefly luciferase reporter gene, abolished reporter gene activity. The region -121 to + 94 contains two well-described regulatory elements, a PMA-responsive element (CRE) near -106 and a GC-rich region containing an Sp1 binding site near +59. Methylation of double-stranded DNA oligonucleotides containing the CRE or the GC-rich region had little or no effect on transcription factor binding. Methylated CpGs may attract co-repressor complexes that contain histone deacetylases (HDAC). However, reporter gene activity of methylated plasmids was not restored by the HDAC inhibitor trichostatin. In conclusion, efficient PLAT gene expression requires a short stretch of unmethylated CpG sites in the proximal promoter. PMID:27973546

  1. PARP-2 regulates cell cycle-related genes through histone deacetylation and methylation independently of poly(ADP-ribosyl)ation

    SciTech Connect

    Liang, Ya-Chen; Hsu, Chiao-Yu; Yao, Ya-Li; Yang, Wen-Ming

    2013-02-01

    Highlights: ► PARP-2 acts as a transcription co-repressor independently of PARylation activity. ► PARP-2 recruits HDAC5, 7, and G9a and generates repressive chromatin. ► PARP-2 is recruited to the c-MYC promoter by DNA-binding factor YY1. ► PARP-2 represses cell cycle-related genes and alters cell cycle progression. -- Abstract: Poly(ADP-ribose) polymerase-2 (PARP-2) catalyzes poly(ADP-ribosyl)ation (PARylation) and regulates numerous nuclear processes, including transcription. Depletion of PARP-2 alters the activity of transcription factors and global gene expression. However, the molecular action of how PARP-2 controls the transcription of target promoters remains unclear. Here we report that PARP-2 possesses transcriptional repression activity independently of its enzymatic activity. PARP-2 interacts and recruits histone deacetylases HDAC5 and HDAC7, and histone methyltransferase G9a to the promoters of cell cycle-related genes, generating repressive chromatin signatures. Our findings propose a novel mechanism of PARP-2 in transcriptional regulation involving specific protein–protein interactions and highlight the importance of PARP-2 in the regulation of cell cycle progression.

  2. SJSZ glycoprotein (38 kDa) inhibits cell cycle and oxidative stress in N-methyl-N'-nitro-N-nitrosoguanidine-induced ICR mice.

    PubMed

    Lee, Jin; Lim, Kye-Taek

    2013-05-01

    The initiation stage of liver cancer is closely related to abnormal cell proliferation as observed for other types of carcinogenesis. Recently, we isolated a glycoprotein from Styrax japonica Siebold et al Zuccarini (SJSZ glycoprotein), which consists of a carbohydrate moiety (52.64%) and a protein moiety (47.36%). In this study, the antitumoric mechanism of SJSZ glycoprotein during the initiation stage in N-Methyl-N`-nitro-N-nitrosoguanidine (MNNG; 40 mg/kg, BW)-induced ICR was investigated. First, we evaluated the activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), thiobarbituric acid-reactive substances (TBARS), and activities of antioxidative enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT)] in mouse liver tissue and serum. The alpha-fetoprotein (AFP), cell cycle-related factors [cyclin D1/ cyclin dependent kinase (CDK) 4], cell cycle inhibitors (CKIs; p53, p21, and p27), and proliferating cell nuclear antigen (PCNA) were then assessed using Western Blot analysis. The results of this analysis showed that the SJSZ glycoprotein (10 mg/kg, BW) decreased the levels of LDH, ALT, TBARS, and the expression of AFP but it increased the activity of hepatic anti-oxidant enzymes (SOD, GPx and CAT). In addition, the SJSZ glycoprotein (10 mg/kg, BW)was shown to decrease the expression of cyclin D1/CDK4 and PCNA and increase the expression of CKIs (p53, p21, and p27). The results in this study indicate that the SJSZ glycoprotein displays anti-oxidative stress and anti-cell proliferation activity in MNNG induced ICR.

  3. Geothermal activity helps life survive glacial cycles.

    PubMed

    Fraser, Ceridwen I; Terauds, Aleks; Smellie, John; Convey, Peter; Chown, Steven L

    2014-04-15

    Climate change has played a critical role in the evolution and structure of Earth's biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this "geothermal glacial refugia" hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species.

  4. Geothermal activity helps life survive glacial cycles

    PubMed Central

    Fraser, Ceridwen I.; Terauds, Aleks; Smellie, John; Convey, Peter; Chown, Steven L.

    2014-01-01

    Climate change has played a critical role in the evolution and structure of Earth’s biodiversity. Geothermal activity, which can maintain ice-free terrain in glaciated regions, provides a tantalizing solution to the question of how diverse life can survive glaciations. No comprehensive assessment of this “geothermal glacial refugia” hypothesis has yet been undertaken, but Antarctica provides a unique setting for doing so. The continent has experienced repeated glaciations that most models indicate blanketed the continent in ice, yet many Antarctic species appear to have evolved in almost total isolation for millions of years, and hence must have persisted in situ throughout. How could terrestrial species have survived extreme glaciation events on the continent? Under a hypothesis of geothermal glacial refugia and subsequent recolonization of nongeothermal regions, we would expect to find greater contemporary diversity close to geothermal sites than in nongeothermal regions, and significant nestedness by distance of this diversity. We used spatial modeling approaches and the most comprehensive, validated terrestrial biodiversity dataset yet created for Antarctica to assess spatial patterns of diversity on the continent. Models clearly support our hypothesis, indicating that geothermally active regions have played a key role in structuring biodiversity patterns in Antarctica. These results provide critical insights into the evolutionary importance of geothermal refugia and the history of Antarctic species. PMID:24616489

  5. The in vitro biological activities of synthetic 18-O-methyl mycalamide B, 10-epi-18-O-methyl mycalamide B and pederin.

    PubMed

    Richter, A; Kocienski, P; Raubo, P; Davies, D E

    1997-04-01

    Mycalamides A and B, which were originally isolated from a marine sponge, show close structural similarity to the insect toxin pederin, and exhibit potent cytotoxicity and antitumour activity. Detailed investigation of the clinical potential of these compounds has been hampered because they are available in only minute quantities from natural sources. We now describe the biological activities of 18-O-methyl mycalamide B, 10-epi-18-O-methyl mycalamide and pederin, all prepared by total synthesis. The activities of 18-O-methyl mycalamide B and pederin were virtually indistinguishable when evaluated in DNA or protein synthesis assays, and in cytotoxicity assays using human carcinoma cell lines (IC50s 0.2-0.6 nM). In all assays, 10-epi-18-O-methyl mycalamide B was 10(3) times less toxic than its diastereoisomer, demonstrating that the cytotoxicity of 18-O-methyl mycalamide B is inseparable from its ability to inhibit protein synthesis. Short-term exposure of squamous carcinoma cells to 18-O-methyl mycalamide B or pederin caused an irreversible inhibition of cellular proliferation and induced cellular necrosis. In contrast, the antiproliferative effects of the compounds on human fibroblasts were reversible and there was no evidence of necrosis. Demonstration that 18-O-methyl mycalamide B and the synthetically less complex molecule, pederin, show some tumour cell toxicity indicates that this novel class of compounds should be subjected to preclinical evaluation.

  6. WHSC1L1-mediated EGFR mono-methylation enhances the cytoplasmic and nuclear oncogenic activity of EGFR in head and neck cancer

    PubMed Central

    Saloura, Vassiliki; Vougiouklakis, Theodore; Zewde, Makda; Deng, Xiaolan; Kiyotani, Kazuma; Park, Jae-Hyun; Matsuo, Yo; Lingen, Mark; Suzuki, Takehiro; Dohmae, Naoshi; Hamamoto, Ryuji; Nakamura, Yusuke

    2017-01-01

    While multiple post-translational modifications have been reported to regulate the function of epidermal growth factor receptor (EGFR), the effect of protein methylation on its function has not been well characterized. In this study, we show that WHSC1L1 mono-methylates lysine 721 in the tyrosine kinase domain of EGFR, and that this methylation leads to enhanced activation of its downstream ERK cascade without EGF stimulation. We also show that EGFR K721 mono-methylation not only affects the function of cytoplasmic EGFR, but also that of nuclear EGFR. WHSC1L1-mediated methylation of EGFR in the nucleus enhanced its interaction with PCNA in squamous cell carcinoma of the head and neck (SCCHN) cells and resulted in enhanced DNA synthesis and cell cycle progression. Overall, our study demonstrates the multifaceted oncogenic function of the protein lysine methyltransferase WHSC1L1 in SCCHN, which is mediated through direct non-histone methylation of the EGFR protein with effects both in its cytoplasmic and nuclear functions. PMID:28102297

  7. Data Assimilation Approach for Forecast of Solar Activity Cycles

    NASA Astrophysics Data System (ADS)

    Kitiashvili, Irina N.

    2016-11-01

    Numerous attempts to predict future solar cycles are mostly based on empirical relations derived from observations of previous cycles, and they yield a wide range of predicted strengths and durations of the cycles. Results obtained with current dynamo models also deviate strongly from each other, thus raising questions about criteria to quantify the reliability of such predictions. The primary difficulties in modeling future solar activity are shortcomings of both the dynamo models and observations that do not allow us to determine the current and past states of the global solar magnetic structure and its dynamics. Data assimilation is a relatively new approach to develop physics-based predictions and estimate their uncertainties in situations where the physical properties of a system are not well-known. This paper presents an application of the ensemble Kalman filter method for modeling and prediction of solar cycles through use of a low-order nonlinear dynamo model that includes the essential physics and can describe general properties of the sunspot cycles. Despite the simplicity of this model, the data assimilation approach provides reasonable estimates for the strengths of future solar cycles. In particular, the prediction of Cycle 24 calculated and published in 2008 is so far holding up quite well. In this paper, I will present my first attempt to predict Cycle 25 using the data assimilation approach, and discuss the uncertainties of that prediction.

  8. Forecast for solar cycle 23 activity: a progress report

    NASA Astrophysics Data System (ADS)

    Ahluwalia, H. S.

    2001-08-01

    At the 25th International Cosmic Ray Conference (ICRC) at Durban, South Africa, I announced the discovery of a three cycle quasi-periodicity in the ion chamber data string assembled by me, for the 1937 to 1994 period (Conf. Pap., v. 2, p. 109, 1997). It corresponded in time with a similar quasi-periodicity observed in the dataset for the planetary index Ap. At the 26th ICRC at Salt Lake City, UT, I reported on our analysis of the Ap data to forecast the amplitude of solar cycle 23 activity (Conf. Pap., v. 2, pl. 260, 1999). I predicted that cycle 23 will be moderate (a la cycle 17), notwithstanding the early exuberant forecasts of some solar astronomers that cycle 23, "may be one of the greatest cycles in recent times, if not the greatest." Sunspot number data up to April 2001 indicate that our forecast appears to be right on the mark. We review the solar, interplanetary and geophysical data and describe the important lessons learned from this experience. 1. Introduction Ohl (1971) was the first to realize that Sun may be sending us a subliminal message as to its intent for its activity (Sunspot Numbers, SSN) in the next cycle. He posited that the message was embedded in the geomagnetic activity (given by sum Kp). Schatten at al (1978) suggested that Ohl hypothesis could be understood on the basis of the model proposed by Babcock (1961) who suggested that the high latitude solar poloidal fields, near a minimum, emerge as the toroidal fields on opposite sides of the solar equator. This is known as the Solar Dynamo Model. One can speculate that the precursor poloidal solar field is entrained in the high speed solar wind streams (HSSWS) from the coronal holes which are observed at Earth's orbit during the descending phase of the previous cycle. The interaction

  9. Understanding Activity Cycles of Solar Type Stars with Kepler

    NASA Astrophysics Data System (ADS)

    Tovar, Guadalupe; Montet, Benjamin; Johnson, John A.

    2017-01-01

    As the era of exploring new worlds and systems advances we seek to answer the question: How common is our Sun? There is considerable evidence about the recurring activity cycles of our Sun but very little is known about the activity cycles of other stars. By calibrating the full frame images from the original Kepler mission that were taken once a month over the course of four years, we are able to do relative photometry on roughly 5 million stars. By building a model of the pixel response function we were able to achieve 0.8% precision photometry. We identify 50,000 solar type stars based on magnitude, surface gravity, and temperature cuts. We observe the relative increase and decrease in brightness of the stars indicating signs of activity cycles similar to our Sun. We continue to explore how a data driven pixel response function model could improve our precision to 0.1% photometry measurements.

  10. Cycle Length Dependence of Stellar Magnetic Activity and Solar Cycle 23

    NASA Astrophysics Data System (ADS)

    Choi, Hwajin; Lee, Jeongwoo; Oh, Suyeon; Kim, Bogyeong; Kim, Hoonkyu; Yi, Yu

    2015-03-01

    Solar cycle (SC) 23 was extraordinarily long with remarkably low magnetic activity. We have investigated whether this is a common behavior of solar-type stars. From the Ca ii H and K line intensities of 111 stars observed at Mount Wilson Observatory from 1966 to 1991, we have retrieved data of all 23 G-type stars and recalculated their cycle lengths using the damped least-squares method for the chromospheric activity index S as a function of time. A regression analysis was performed to find relations between the derived cycle length, Pavg, and the index for excess chromospheric emission, RHK\\prime . As a noteworthy result, we found a segregation between young and old solar-type stars in the cycle length-activity correlation. We incorporated the relation for the solar-type stars into the previously known rule for stellar chromospheric activity and brightness to estimate the variation of solar brightness from SC 22 to SC 23 as (0.12 ± 0.06)%, much higher than the actual variation of total solar irradiance (TSI) ≤0.02%. We have then examined solar spectral irradiance (SSI) to find a good phase correlation with a sunspot number in the wavelength range of 170-260 nm, which is close to the spectral range effective in heating the Earth’s atmosphere. Therefore, it appears that SSI rather than TSI is a good indicator of the chromospheric activity, and its cycle length dependent variation would be more relevant to the possible role of the Sun in the cyclic variation of the Earth’s atmosphere.

  11. Effect of salinity on mercury methylating benthic microbes and their activities in Great Salt Lake, Utah.

    PubMed

    Boyd, Eric S; Yu, Ri-Qing; Barkay, Tamar; Hamilton, Trinity L; Baxter, Bonnie K; Naftz, David L; Marvin-DiPasquale, Mark

    2017-03-01

    Surface water and biota from Great Salt Lake (GSL) contain some of the highest documented concentrations of total mercury (THg) and methylmercury (MeHg) in the United States. In order to identify potential biological sources of MeHg and controls on its production in this ecosystem, THg and MeHg concentrations, rates of Hg(II)-methylation and MeHg degradation, and abundances and compositions of archaeal and bacterial 16 rRNA gene transcripts were determined in sediment along a salinity gradient in GSL. Rates of Hg(II)-methylation were inversely correlated with salinity and were at or below the limits of detection in sediment sampled from areas with hypersaline surface water. The highest rates of Hg(II)-methylation were measured in sediment with low porewater salinity, suggesting that benthic microbial communities inhabiting less saline environments are supplying the majority of MeHg in the GSL ecosystem. The abundance of 16S rRNA gene transcripts affiliated with the sulfate reducer Desulfobacterium sp. was positively correlated with MeHg concentrations and Hg(II)-methylation rates in sediment, indicating a potential role for this taxon in Hg(II)-methylation in low salinity areas of GSL. Reactive inorganic Hg(II) (a proxy used for Hg(II) available for methylation) and MeHg concentrations were inversely correlated with salinity. Thus, constraints imposed by salinity on Hg(II)-methylating populations and the availability of Hg(II) for methylation are inferred to result in higher MeHg production potentials in lower salinity environments. Benthic microbial MeHg degradation was also most active in lower salinity environments. Collectively, these results suggest an important role for sediment anoxia and microbial sulfate reducers in the production of MeHg in low salinity GSL sub-habitats and may indicate a role for salinity in constraining Hg(II)-methylation and MeHg degradation activities by influencing the availability of Hg(II) for methylation.

  12. Methylation of the mouse hprt gene differs on the active and inactive X chromosomes.

    PubMed Central

    Lock, L F; Melton, D W; Caskey, C T; Martin, G R

    1986-01-01

    It has been proposed that DNA methylation is involved in the mechanism of X inactivation, the process by which equivalence of levels of X-linked gene products is achieved in female (XX) and male (XY) mammals. In this study, Southern blots of female and male DNA digested with methylation-sensitive restriction endonucleases and hybridized to various portions of the cloned mouse hprt gene were compared, and sites within the mouse hprt gene were identified that are differentially methylated in female and male cells. The extent to which these sites are methylated when carried on the active and inactive X chromosomes was directly determined in a similar analysis of DNA from clonal cell lines established from a female embryo derived from a mating of two species of mouse, Mus musculus and Mus caroli. The results revealed two regions of differential methylation in the mouse hprt gene. One region, in the first intron of the gene, includes four sites that are completely unmethylated when carried on the active X and extensively methylated when carried on the inactive X. These same sites are extensively demethylated in hprt genes reactivated either spontaneously or after 5-azacytidine treatment. The second region includes several sites in the 3' 20kilobases of the gene extending from exon 3 to exon 9 that show the converse pattern; i.e., they are completely methylated when carried on the active X and completely unmethylated when carried on the inactive X. At least one of these sites does not become methylated after reactivation of the gene. The results of this study, together with the results of previous studies by others of the human hprt gene, indicate that these regions of differential methylation on the active and inactive X are conserved between mammalian species. Furthermore, the data described here are consistent with the idea that at least the sites in the 5' region of the gene play a role in the X inactivation phenomenon and regulation of expression of the mouse hprt

  13. The onset of the solar active cycle 22

    NASA Technical Reports Server (NTRS)

    Ahluwalia, H. S.

    1989-01-01

    There is a great deal of interest in being able to predict the main characteristics of a solar activity cycle (SAC). One would like to know, for instance, how large the amplitude (R sub m) of a cycle is likely to be, i.e., the annual mean of the sunspot numbers at the maximum of SAC. Also, how long a cycle is likely to last, i.e., its period. It would also be interesting to be able to predict the details, like how steep the ascending phase of a cycle is likely to be. Questions like these are of practical importance to NASA in planning the launch schedule for the low altitude, expensive spacecrafts like the Hubble Space Telescope, the Space Station, etc. Also, one has to choose a proper orbit, so that once launched the threat of an atmospheric drag on the spacecraft is properly taken into account. Cosmic ray data seem to indicate that solar activity cycle 22 will surpass SAC 21 in activity. The value of R sub m for SAC 22 may approach that of SAC 19. It would be interesting to see whether this prediction is borne out. Researchers are greatly encouraged to proceed with the development of a comprehensive prediction model which includes information provided by cosmic ray data.

  14. Connection between solar activity cycles and grand minima generation

    NASA Astrophysics Data System (ADS)

    Vecchio, A.; Lepreti, F.; Laurenza, M.; Alberti, T.; Carbone, V.

    2017-03-01

    Aims: The revised dataset of sunspot and group numbers (released by WDC-SILSO) and the sunspot number reconstruction based on dendrochronologically dated radiocarbon concentrations have been analyzed to provide a deeper characterization of the solar activity main periodicities and to investigate the role of the Gleissberg and Suess cycles in the grand minima occurrence. Methods: Empirical mode decomposition (EMD) has been used to isolate the time behavior of the different solar activity periodicities. A general consistency among the results from all the analyzed datasets verifies the reliability of the EMD approach. Results: The analysis on the revised sunspot data indicates that the highest energy content is associated with the Schwabe cycle. In correspondence with the grand minima (Maunder and Dalton), the frequency of this cycle changes to longer timescales of 14 yr. The Gleissberg and Suess cycles, with timescales of 60-120 yr and 200-300 yr, respectively, represent the most energetic contribution to sunspot number reconstruction records and are both found to be characterized by multiple scales of oscillation. The grand minima generation and the origin of the two expected distinct types of grand minima, Maunder and longer Spörer-like, are naturally explained through the EMD approach. We found that the grand minima sequence is produced by the coupling between Gleissberg and Suess cycles, the latter being responsible for the most intense and longest Spörer-like minima (with typical duration longer than 80 yr). Finally, we identified a non-solar component, characterized by a very long scale oscillation of 7000 yr, and the Hallstatt cycle ( 2000 yr), likely due to the solar activity. Conclusions: These results provide new observational constraints on the properties of the solar cycle periodicities, the grand minima generation, and thus the long-term behavior of the solar dynamo.

  15. MAGNETIC ACTIVITY CYCLES IN THE EXOPLANET HOST STAR {epsilon} ERIDANI

    SciTech Connect

    Metcalfe, T. S.; Mathur, S.; Buccino, A. P.; Mauas, P. J. D.; Petrucci, R.; Brown, B. P.; Soderblom, D. R.; Henry, T. J.; Hall, J. C.; Basu, S.

    2013-02-01

    The active K2 dwarf {epsilon} Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in {epsilon} Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 {+-} 0.03 years and 12.7 {+-} 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called 'active' and 'inactive' sequences as proposed by Boehm-Vitense. Finally, based on the observed properties of {epsilon} Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

  16. First evidence of DNA methylation in insect Tribolium castaneum: environmental regulation of DNA methylation within heterochromatin.

    PubMed

    Feliciello, Isidoro; Parazajder, Josip; Akrap, Ivana; Ugarković, Durđica

    2013-05-01

    DNA methylation has been studied in many eukaryotic organisms, in particular vertebrates, and was implicated in developmental and phenotypic variations. Little is known about the role of DNA methylation in invertebrates, although insects are considered as excellent models for studying the evolution of DNA methylation. In the red flour beetle, Tribolium castaneum (Tenebrionidae, Coleoptera), no evidence of DNA methylation has been found till now. In this paper, a cytosine methylation in Tribolium castaneum embryos was detected by methylation sensitive restriction endonucleases and immuno-dot blot assay. DNA methylation in embryos is followed by a global demethylation in larvae, pupae and adults. DNA demethylation seems to proceed actively through 5-hydroxymethylcytosine, most probably by the action of TET enzyme. Bisulfite sequencing of a highly abundant satellite DNA located in pericentromeric heterochromatin revealed similar profile of cytosine methylation in adults and embryos. Cytosine methylation was not only restricted to CpG sites but was found at CpA, CpT and CpC sites. In addition, complete cytosine demethylation of heterochromatic satellite DNA was induced by heat stress. The results reveal existence of DNA methylation cycling in T. castaneum ranging from strong overall cytosine methylation in embryos to a weak DNA methylation in other developmental stages. Nevertheless, DNA methylation is preserved within heterochromatin during development, indicating its role in heterochromatin formation and maintenance. It is, however, strongly affected by heat stress, suggesting a role for DNA methylation in heterochromatin structure modulation during heat stress response.

  17. Wounding coordinately induces cell wall protein, cell cycle and pectin methyl esterase genes involved in tuber closing layer and wound periderm development.

    PubMed

    Neubauer, Jonathan D; Lulai, Edward C; Thompson, Asunta L; Suttle, Jeffrey C; Bolton, Melvin D

    2012-04-15

    Little is known about the coordinate induction of genes that may be involved in agriculturally important wound-healing events. In this study, wound-healing events were determined together with wound-induced expression profiles of selected cell cycle, cell wall protein, and pectin methyl esterase genes using two diverse potato genotypes and two harvests (NDTX4271-5R and Russet Burbank tubers; 2008 and 2009 harvests). By 5 d after wounding, the closing layer and a nascent phellogen had formed. Phellogen cell divisions generated phellem layers until cessation of cell division at 28 d after wounding for both genotypes and harvests. Cell cycle genes encoding epidermal growth factor binding protein (StEBP), cyclin-dependent kinase B (StCDKB) and cyclin-dependent kinase regulatory subunit (StCKS1At) were induced by 1 d after wounding; these expressions coordinated with related phellogen formation and the induction and cessation of phellem cell formation. Genes encoding the structural cell wall proteins extensin (StExt1) and extensin-like (StExtlk) were dramatically up-regulated by 1-5 d after wounding, suggesting involvement with closing layer and later phellem cell layer formation. Wounding up-regulated pectin methyl esterase genes (StPME and StPrePME); StPME expression increased during closing layer and phellem cell formation, whereas maximum expression of StPrePME occurred at 5-14 d after wounding, implicating involvement in later modifications for closing layer and phellem cell formation. The coordinate induction and expression profile of StTLRP, a gene encoding a cell wall strengthening "tyrosine-and lysine-rich protein," suggested a role in the formation of the closing layer followed by phellem cell generation and maturation. Collectively, the genes monitored were wound-inducible and their expression profiles markedly coordinated with closing layer formation and the index for phellogen layer meristematic activity during wound periderm development; results were more

  18. Enhanced HSP70 lysine methylation promotes proliferation of cancer cells through activation of Aurora kinase B

    PubMed Central

    Cho, Hyun-Soo; Shimazu, Tadahiro; Toyokawa, Gouji; Daigo, Yataro; Maehara, Yoshihiko; Hayami, Shinya; Ito, Akihiro; Masuda, Ken; Ikawa, Noriko; Field, Helen I.; Tsuchiya, Eiju; Ohnuma, Shin-ichi; Ponder, Bruce A.J.; Yoshida, Minoru; Nakamura, Yusuke; Hamamoto, Ryuji

    2012-01-01

    Although heat-shock protein 70 (HSP70), an evolutionarily highly conserved molecular chaperone, is known to be post-translationally modified in various ways such as phosphorylation, ubiquitination and glycosylation, physiological significance of lysine methylation has never been elucidated. Here we identify dimethylation of HSP70 at Lys-561 by SETD1A. Enhanced HSP70 methylation was detected in various types of human cancer by immunohistochemical analysis, although the methylation was barely detectable in corresponding non-neoplastic tissues. Interestingly, methylated HSP70 predominantly localizes to the nucleus of cancer cells, whereas most of the HSP70 protein locates to the cytoplasm. Nuclear HSP70 directly interacts with Aurora kinase B (AURKB) in a methylation-dependent manner and promotes AURKB activity in vitro and in vivo. We also find that methylated HSP70 has a growth-promoting effect in cancer cells. Our findings demonstrate a crucial role of HSP70 methylation in human carcinogenesis. PMID:22990868

  19. Activities of natural methyl farnesoids on pupariation and metamorphosis of Drosophila melanogaster

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl farnesoate (MF) and juvenile hormone (JH III), which respectively bind to the receptors USP and MET, and bisepoxy JH III (bisJHIII) were assessed for several activities during Drosophila larval development, and during prepupal development to eclosed adults. Dietary MF and JH III were similar...

  20. DIFFERENTIAL ACTIVATION OF AP-1 IN HUMAN BLADDER EPITHELIAL CELLS BY INORGANIC AND METHYLATED ARSENICALS

    EPA Science Inventory

    Differential Activation of AP-1 in Human Bladder Epithelial Cells by Inorganic and Methylated Arsenicals

    Zuzana Drobna, Ilona Jaspers, David J. Thomas, and Miroslav Styblo

    ABSTRACT

    Epidemiological studies have linked chronic ingestion of drinking water contai...

  1. Esterification and Transesterification of greases to fatty acid methyl esters with highly active diphenylamine salts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diphenylamine sulfate (DPAS) and diphenylamine hydrochloride (DPACl) salts were found to be highly active catalysts for esterification and transesterification of inexpensive greases to fatty acid methyl esters (FAME). In the presence of catalytic amounts of DPAS or DPACl and excess methanol, the fr...

  2. Esterification and transesterification of greases to fatty acid methyl esters with highly active diphanylammonium salts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have conducted an investigation designed to identify alternate catalysts for the production of fatty acid methyl esters (FAME) to be used as biodiesel. Diphenylammonium sulfate (DPAS) and diphenylammonium chloride (DPA-HCl) salts were found to be highly active homogeneous catalysts for the simu...

  3. RNA synthesis in cells infected with herpes simple virus. XIII. Differences in the methylation patterns of viral RNA during the reproductive cycle.

    PubMed Central

    Bartkoski, M; Roizman, B

    1976-01-01

    Herpex simplex virus 1 (HSV-1) RNA labeled with with [methyl-3H] methionine at various times during the infectious cycle and purified by hybridization to viral DNA was analyzed for the presence of methylated nucleotides. The data indicate the following. (i) RNA labeled from 0 to 14 h postinfection and accumulating in the cytoplasm contained internal base-methylated nucleotides and terminal oligonucleotides consistent with the structure 7mG(5')ppp-(5')XmpYmpNp. Similar methylated nucleotides and oligonucleotides were also found in viral RNA accumulating in the cytoplasm of cells treated with cycloheximide from the time of infection. Previous studies (M. Kozak and B. Roizman, 1974) have shown that, whereas the RNA accumulating in the 14-h infected cells contains all of the sequences functioning as mRNA throughout infection, the RNA accumulating in the cytoplasm of cycloheximide-treated cells is associated with polyribosomes synthesizing the earliest (alpha) group of polypeptides specified by the virus. (ii) Cytoplasmic viral RNA from cells labeled 11 to 14 h postinfection as well as the total adenylated RNA in the cytoplasm and polyribosomes labeled in the same fashion contained the terminal oligonucleotide but not the internal base-methylated nucleotide. PMID:186635

  4. Active loss of DNA methylation in two-cell stage goat embryos.

    PubMed

    Park, Jung S; Lee, Doosoo; Cho, Sunwha; Shin, Sang-Tae; Kang, Yong-Kook

    2010-01-01

    Early mammalian embryos are thought to gain nuclear totipotency through DNA methylation reprogramming (DMR). By this process, DNA methylation patterns acquired during gametogenesis that are unnecessary for zygotic development are erased. The DMR patterns of various mammalian species have been studied; however, they do not seem to have a conserved pattern. We examined early goat embryos to find conforming rules underlying mammalian DMR patterns. Immunocytochemical results showed that the overall level of DNA methylation was not greatly changed during the pronucleus stage. At the two-cell stage, active demethylation occurred and simultaneously affected both parental DNAs, resulting in a global loss of 5-methylcytosine. The level of DNA methylation was lowest in the four-cell stage, with increased de novo methylation during the eight-cell stage. Histone H3-lysine 9 was gradually trimethylated in the sperm-derived chromatin, continuing from the pronucleus stage through the two-cell stage. This goat DMR pattern is novel and distinct from the DMRs of other mammalian species. The more mammalian species we included for DMR analysis, the more multifarious patterns we obtained, adding an extra diversity each time to the known mammalian DMR patterns. Nevertheless, the evolutionary significance and developmental consequence of such diverse DMR patterns are currently unknown.

  5. The evolution and orientation of early cycle 22 active regions

    NASA Technical Reports Server (NTRS)

    Cannon, Anne T.; Marquette, William H.

    1991-01-01

    The evolution of six major active regions which appeared during the first phase of the present solar cycle (cycle 22) has been studied. It was found that the northern hemisphere regions exhibited a broad range of evolutionary behavior in which the commonly accepted 'normal pattern' (whereby the follower flux moves preferentially polewards ahead of the leader flux) is represented at one end of the range. At the other end of the range, the leader flux is displaced polewards of the follower flux. In the latter cases equatorward extensions of the polar coronal hole are noted.

  6. Conjugates of methylated cyclodextrin derivatives and hydroxyethyl starch (HES): Synthesis, cytotoxicity and inclusion of anaesthetic actives

    PubMed Central

    Markenstein, Lisa; Appelt-Menzel, Antje; Metzger, Marco

    2014-01-01

    Summary The mono-6-deoxy-6-azides of 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and randomly methylated-β-cyclodextrin (RAMEB) were conjugated to propargylated hydroxyethyl starch (HES) by Cu+-catalysed [2 + 3] cycloaddition. The resulting water soluble polymers showed lower critical solution temperatures (LCST) at 52.5 °C (DIMEB-HES) and 84.5 °C (RAMEB-HES), respectively. LCST phase separations could be completely avoided by the introduction of a small amount of carboxylate groups at the HES backbone. The methylated CDs conjugated to the HES backbone exhibited significantly lower cytotoxicities than the corresponding monomeric CD derivatives. Since the binding potentials of these CD conjugates were very high, they are promising candidates for new oral dosage forms of anaesthetic actives. PMID:25670977

  7. Histone H3 K79 methylation states play distinct roles in UV-induced sister chromatid exchange and cell cycle checkpoint arrest in Saccharomyces cerevisiae

    PubMed Central

    Rossodivita, Alyssa A.; Boudoures, Anna L.; Mecoli, Jonathan P.; Steenkiste, Elizabeth M.; Karl, Andrea L.; Vines, Eudora M.; Cole, Arron M.; Ansbro, Megan R.; Thompson, Jeffrey S.

    2014-01-01

    Histone post-translational modifications have been shown to contribute to DNA damage repair. Prior studies have suggested that specific H3K79 methylation states play distinct roles in the response to UV-induced DNA damage. To evaluate these observations, we examined the effect of altered H3K79 methylation patterns on UV-induced G1/S checkpoint response and sister chromatid exchange (SCE). We found that the di- and trimethylated states both contribute to activation of the G1/S checkpoint to varying degrees, depending on the synchronization method, although methylation is not required for checkpoint in response to high levels of UV damage. In contrast, UV-induced SCE is largely a product of the trimethylated state, which influences the usage of gene conversion versus popout mechanisms. Regulation of H3K79 methylation by H2BK123 ubiquitylation is important for both checkpoint function and SCE. H3K79 methylation is not required for the repair of double-stranded breaks caused by transient HO endonuclease expression, but does play a modest role in survival from continuous exposure. The overall results provide evidence for the participation of H3K79 methylation in UV-induced recombination repair and checkpoint activation, and further indicate that the di- and trimethylation states play distinct roles in these DNA damage response pathways. PMID:24748660

  8. Molecular characterization, expression and methylation status analysis of BMP4 gene in skin tissue of Liaoning cashmere goat during hair follicle cycle.

    PubMed

    Bai, Wen L; Dang, Yun L; Wang, Jiao J; Yin, Rong H; Wang, Ze Y; Zhu, Yu B; Cong, Yu Y; Xue, Hui L; Deng, Liang; Guo, Dan; Wang, Shi Q; Yang, Shu H

    2016-08-01

    Bone morphogenetic protein 4 (BMP4) is a member of the bone morphogenetic protein family (BMPs). It is involved in the development and cycle of hair follicle, as well as, is thought to be a potential candidate gene for cashmere traits in goats. In the present study, we isolated and characterized a full-length open reading frame (ORF) of BMP4 cDNA from the skin tissue of Liaoning cashmere goat, and investigated the transcriptional pattern and methylation status of BMP4 gene in skin tissue of this breed during different stages of hair follicle cycle. The sequence analysis indicated that the isolated cDNA was 1264-bp in length containing a complete ORF of 1230-bp. It encoded a precursor peptide of 409 amino acids with a signal peptide of 19 amino acids. The structural analysis indicated that goat BMP4 contains typical TGF-β propeptide and TGF-β domains. In skin tissue, BMP4 is generally transcribed in an ascendant pattern from anagen to telogen. The methylation level of 5' flanking regulatory region of BMP4 gene might be involved in its mRNA expression in skin tissue: a higher BMP4 methylation level in skin coincides with a lower expression of BMP4 mRNA. These results from the present work provided a foundation for further insight into the functional and regulatory characteristics of BMP4 in the development and cycle of hair follicle in Liaoning Cashmere goat.

  9. Impacts of Activated Carbon Amendment on Hg Methylation, Demethylation and Microbial Activity in Marsh Soils

    NASA Astrophysics Data System (ADS)

    Gilmour, C. C.; Ghosh, U.; Santillan, E. F. U.; Soren, A.; Bell, J. T.; Butera, D.; McBurney, A. W.; Brown, S.; Henry, E.; Vlassopoulos, D.

    2015-12-01

    In-situ sorbent amendments are a low-impact approach for remediation of contaminants in sediments, particular in habitats like wetlands that provide important ecosystem services. Laboratory microcosm trials (Gilmour et al. 2013) and early field trials show that activated carbon (AC) can effectively increase partitioning of both inorganic Hg and methylmercury to the solid phase. Sediment-water partitioning can serve as a proxy for Hg and MeHg bioavailability in soils. One consideration in using AC in remediation is its potential impact on organisms. For mercury, a critical consideration is the potential impact on net MeHg accumulation and bioavailability. In this study, we specifically evaluated the impact of AC on rates of methylmercury production and degradation, and on overall microbial activity, in 4 different Hg-contaminated salt marsh soils. The study was done over 28 days in anaerobic, sulfate-reducing slurries. A double label of enriched mercury isotopes (Me199Hg and inorganic 201Hg) was used to separately follow de novo Me201Hg production and Me199Hg degradation. AC amendments decreased both methylation and demethylation rate constants relative to un-amended controls, but the impact on demethylation was stronger. The addition of 5% (dry weight) regenerated AC to soil slurries drove demethylation rate constants to nearly zero; i.e. MeHg sorption to AC almost totally blocked its degradation. The net impact was increased solid phase MeHg concentrations in some of the soil slurries with the highest methylation rate constants. However, the net impact of AC amendments was to increase MeHg (and inorganic Hg) partitioning to the soil phase and decrease concentrations in the aqueous phase. AC significantly decreased aqueous phase inorganic Hg and MeHg concentrations after 28 days. Overall, the efficacy of AC in reducing aqueous MeHg was highest in the soils with the highest MeHg concentrations. The AC addition did not significantly impact microbial activity, as

  10. In vitro reconstitution and activity of a C/D box methylation guide ribonucleoprotein complex

    PubMed Central

    Omer, Arina D.; Ziesche, Sonia; Ebhardt, Holger; Dennis, Patrick P.

    2002-01-01

    The genomes of hyperthermophilic Archaea encode dozens of methylation guide, C/D box small RNAs that guide 2′-O-methylation of ribose to specific sites in rRNA and various tRNAs. The genes encoding the Sulfolobus homologues of eukaryotic proteins that are known to be present in C/D box small nucleolar ribonucleoprotein (snoRNP) complexes were cloned, and the proteins (aFIB, aNOP56, and aL7a) were expressed and purified. The purified proteins along with an in vitro transcript of the Sulfolobus sR1 small RNA were reconstituted in vitro, into an RNP complex. The order of assembly of the three proteins onto the RNA was aL7a, aNOP56, and aFIB. The complex was active in targeting S-adenosyl methionine (SAM)-dependent, site-specific 2′-O-methylation of ribose to a short fragment of ribosomal RNA (rRNA) that was complementary to the D box guide region of the sR1 small RNA. The presence of aFIB was essential for methylation; mutant proteins having amino acid replacements in the SAM-binding motif of aFIB were able to assemble into an RNP complex, but the resulting complexes were defective in methylation activity. These experiments define the minimal number of components and the conditions required to achieve in vitro RNA guide-directed 2′-O-methylation of ribose in a target RNA. PMID:11959980

  11. Background magnetic fields during last three cycles of solar activity

    NASA Astrophysics Data System (ADS)

    Andryeyeva, O. A.; Stepanian, N. N.

    2008-07-01

    This paper describes our studies of evolution of the solar magnetic field with different sign and field strength in the range from -100 G to 100 G. The structure and evolution of large-scale magnetic fields on the Sun during the last 3 cycles of solar activity is investigated using magnetograph data from the Kitt Peak Solar Observatory. This analysis reveals two groups of the large-scale magnetic fields evolving differently during the cycles. The first group is represented by relatively weak background fields, and is best observed in the range of 3-10 Gauss. The second group is represented by stronger fields of 75-100 Gauss. The spatial and temporal properties of these groups are described and compared with the total magnetic flux. It is shown that the anomalous behaviour of the total flux during the last cycle can be found only in the second group

  12. Induction of Methyl Tertiary Butyl Ether (MTBE)-Oxidizing Activity in Mycobacterium vaccae JOB5 by MTBE

    PubMed Central

    Johnson, Erika L.; Smith, Christy A.; O'Reilly, Kirk T.; Hyman, Michael R.

    2004-01-01

    Alkane-grown cells of Mycobacterium vaccae JOB5 cometabolically degrade the gasoline oxygenate methyl tertiary butyl ether (MTBE) through the activities of an alkane-inducible monooxygenase and other enzymes in the alkane oxidation pathway. In this study we examined the effects of MTBE on the MTBE-oxidizing activity of M. vaccae JOB5 grown on diverse nonalkane substrates. Carbon-limited cultures were grown on glycerol, lactate, several sugars, and tricarboxylic acid cycle intermediates, both in the presence and absence of MTBE. In all MTBE-containing cultures, MTBE consumption occurred and tertiary butyl alcohol (TBA) and tertiary butyl formate accumulated in the culture medium. Acetylene, a specific inactivator of alkane- and MTBE-oxidizing activities, fully inhibited MTBE consumption and product accumulation but had no other apparent effects on culture growth. The MTBE-dependent stimulation of MTBE-oxidizing activity in fructose- and glycerol-grown cells was saturable with respect to MTBE concentration (50% saturation level = 2.4 to 2.75 mM), and the onset of MTBE oxidation in glycerol-grown cells was inhibited by both rifampin and chloramphenicol. Other oxygenates (TBA and tertiary amyl methyl ether) also induced the enzyme activity required for their own degradation in glycerol-grown cells. Presence of MTBE also promoted MTBE oxidation in cells grown on organic acids, compounds that are often found in anaerobic, gasoline-contaminated environments. Experiments with acid-grown cells suggested induction of MTBE-oxidizing activity by MTBE is subject to catabolite repression. The results of this study are discussed in terms of their potential implications towards our understanding of the role of cometabolism in MTBE and TBA biodegradation in gasoline-contaminated environments. PMID:14766585

  13. SOLAR ROTATION RATE DURING THE CYCLE 24 MINIMUM IN ACTIVITY

    SciTech Connect

    Antia, H. M.; Basu, Sarbani E-mail: sarbani.basu@yale.ed

    2010-09-01

    The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to now, we study the differences in the nature of the solar rotation between the minima of cycles 23 and 24. We find that there are significant differences between the rotation rates during the two minima. There are differences in the zonal-flow pattern too. We find that the band of fast rotating region close to the equator bifurcated around 2005 and recombined by 2008. This behavior is different from that during the cycle 23 minimum. By autocorrelating the zonal-flow pattern with a time shift, we find that in terms of solar dynamics, solar cycle 23 lasted for a period of 11.7 years, consistent with the result of Howe et al. (2009). The autocorrelation coefficient also confirms that the zonal-flow pattern penetrates through the convection zone.

  14. Geissoschizine methyl ether N-oxide, a new alkaloid with antiacetylcholinesterase activity from Uncaria rhynchophylla.

    PubMed

    Jiang, Wei-Wei; Su, Jia; Wu, Xing-De; He, Juan; Peng, Li-Yan; Cheng, Xiao; Zhao, Qin-Shi

    2015-01-01

    Geissoschizine methyl ether N-oxide, a new oxindole alkaloid, along with 14 known alkaloids, was isolated from the aerial part of Uncaria rhynchophylla. Their structures were identified by comprehensive spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In vitro acetylcholinesterase (AChE) inhibitory activity assay showed that the new compound exhibited anti-AChE activity with IC₅₀ value of 23.4 μM.

  15. Cycle-to-cycle variability of neuromuscular activity in Aplysia feeding behavior.

    PubMed

    Horn, Charles C; Zhurov, Yuriy; Orekhova, Irina V; Proekt, Alex; Kupfermann, Irving; Weiss, Klaudiusz R; Brezina, Vladimir

    2004-07-01

    Aplysia consummatory feeding behavior, a rhythmic cycling of biting, swallowing, and rejection movements, is often said to be stereotyped. Yet closer examination shows that cycles of the behavior are very variable. Here we have quantified and analyzed the variability at several complementary levels in the neuromuscular system. In reduced preparations, we recorded the motor programs produced by the central pattern generator, firing of the motor neurons B15 and B16, and contractions of the accessory radula closer (ARC) muscle while repetitive programs were elicited by stimulation of the esophageal nerve. In other similar experiments, we recorded firing of motor neuron B48 and contractions of the radula opener muscle. In intact animals, we implanted electrodes to record nerve or ARC muscle activity while the animals swallowed controlled strips of seaweed or fed freely. In all cases, we found large variability in all parameters examined. Some of this variability reflected systematic, slow, history-dependent changes in the character of the central motor programs. Even when these trends were factored out, however, by focusing only on the differences between successive cycles, considerable variability remained. This variability was apparently random. Nevertheless, it too was the product of central history dependency because regularizing merely the high-level timing of the programs also regularized many of the downstream neuromuscular parameters. Central motor program variability thus appears directly in the behavior. With regard to the production of functional behavior in any one cycle, the large variability may indicate broad tolerances in the operation of the neuromuscular system. Alternatively, some cycles of the behavior may be dysfunctional. Overall, the variability may be part of an optimal strategy of trial, error, and stabilization that the CNS adopts in an uncertain environment.

  16. Physical properties and biological activities of hesperetin and naringenin in complex with methylated β-cyclodextrin

    PubMed Central

    Sangpheak, Waratchada; Kicuntod, Jintawee; Schuster, Roswitha; Rungrotmongkol, Thanyada; Wolschann, Peter; Kungwan, Nawee; Viernstein, Helmut

    2015-01-01

    Summary The aim of this work is to improve physical properties and biological activities of the two flavanones hesperetin and naringenin by complexation with β-cyclodextrin (β-CD) and its methylated derivatives (2,6-di-O-methyl-β-cyclodextrin, DM-β-CD and randomly methylated-β-CD, RAMEB). The free energies of inclusion complexes between hesperetin with cyclodextrins (β-CD and DM-β-CD) were theoretically investigated by molecular dynamics simulation. The free energy values obtained suggested a more stable inclusion complex with DM-β-CD. The vdW force is the main guest–host interaction when hesperetin binds with CDs. The phase solubility diagram showed the formation of a soluble complex of AL type, with higher increase in solubility and stability when hesperetin and naringenin were complexed with RAMEB. Solid complexes were prepared by freeze-drying, and the data from differential scanning calorimetry (DSC) confirmed the formation of inclusion complexes. The data obtained by the dissolution method showed that complexation with RAMEB resulted in a better release of both flavanones to aqueous solution. The flavanones-β-CD/DM-β-CD complexes demonstrated a similar or a slight increase in anti-inflammatory activity and cytotoxicity towards three different cancer cell lines. The overall results suggested that solubilities and bioactivities of both flavanones were increased by complexation with methylated β-CDs. PMID:26877798

  17. Methyl Salicylate Level Increase in Flax after Fusarium oxysporum Infection Is Associated with Phenylpropanoid Pathway Activation

    PubMed Central

    Boba, Aleksandra; Kostyn, Kamil; Kostyn, Anna; Wojtasik, Wioleta; Dziadas, Mariusz; Preisner, Marta; Szopa, Jan; Kulma, Anna

    2017-01-01

    Flax (Linum usitatissimum) is a crop plant valued for its oil and fiber. Unfortunately, large losses in cultivation of this plant are caused by fungal infections, with Fusarium oxysporum being one of its most dangerous pathogens. Among the plant's defense strategies, changes in the expression of genes of the shikimate/phenylpropanoid/benzoate pathway and thus in phenolic contents occur. Among the benzoates, salicylic acid, and its methylated form methyl salicylate play an important role in regulating plants' response to stress conditions. Upon treatment of flax plants with the fungus we found that methyl salicylate content increased (4.8-fold of the control) and the expression profiles of the analyzed genes suggest that it is produced most likely from cinnamic acid, through the β-oxidative route. At the same time activation of some genes involved in lignin and flavonoid biosynthesis was observed. We suggest that increased methyl salicylate biosynthesis during flax response to F. oxysporum infection may be associated with phenylpropanoid pathway activation. PMID:28163709

  18. Antibacterial activity and cytocompatibility of chitosan-N-hydroxy-2,3-propyl-N methyl-N,N-diallylammonium methyl sulfate.

    PubMed

    Jou, Chi-Hsiung

    2011-11-01

    A water-soluble quaternary ammonium salt of chitosan, chitosan-N-hydroxy-2,3-propyl-N-methyl-N,N-diallylammonium methyl sulfate (MDAACS), was synthesized by reacting chitosan with methyl diallyl ammonium salt (MDAA). The results of water contact angle and swelling ratio showed that the membrane of MDAACS was more hydrophilic than chitosan. The antibacterial activities of MDAACS against Staphylococcus aureus and Klebsiella pneumoniae were evaluated with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The results showed that the antibacterial activity of MDAACS was higher than that of chitosan. The cytocompatibility was evaluated in vitro with L929 fibroblast proliferation based on MTT colorimetric assay. The results showed that cell growth was much higher on MDAACS than on chitosan.

  19. A single amino acid substitution confers enhanced methylation activity of mammalian Dnmt3b on chromatin DNA.

    PubMed

    Shen, Li; Gao, Ge; Zhang, Ying; Zhang, He; Ye, Zhiqiang; Huang, Shichao; Huang, Jinyan; Kang, Jiuhong

    2010-10-01

    Dnmt3a and Dnmt3b are paralogous enzymes responsible for de novo DNA methylation but with distinguished biological functions. In mice, disruption of Dnmt3b but not Dnmt3a causes global DNA hypomethylation, especially in repetitive sequences, which comprise the large majority of methylated DNA in the genome. By measuring DNA methylation activity of Dnmt3a and Dnmt3b homologues from five species, we found that mammalian Dnmt3b possessed significantly higher methylation activity on chromatin DNA than Dnmt3a and non-mammalian Dnmt3b. Sequence comparison and mutagenesis experiments identified a single amino acid substitution (I662N) in mammalian Dnmt3b as being crucial for its high chromatin DNA methylation activity. Further mechanistic studies demonstrated this substitution markedly enhanced the binding of Dnmt3b to nucleosomes and hence increased the chromatin DNA methylation activity. Moreover, this substitution was crucial for Dnmt3b to efficiently methylate repetitive sequences, which increased dramatically in mammalian genomes. Consistent with our observation that Dnmt3b evolved more rapidly than Dnmt3a during the emergence of mammals, these results demonstrated that the I662N substitution in mammalian Dnmt3b conferred enhanced chromatin DNA methylation activity and contributed to functional adaptation in the epigenetic system.

  20. Impact of activation process on fog life cycle

    NASA Astrophysics Data System (ADS)

    Mazoyer, Marie; Burnet, Frédéric; Lac, Christine; Roberts, Greg; Dupont, Jean-Charles; Haeffelin, Martial; Elias, Thierry

    2015-04-01

    Fogs are complex meteorological system dealing with fine scale processes. Subtle interaction between radiative, dynamic, turbulent and microphysic processes can lead to different fog life cycle, which make prediction difficult. The droplets that composed fogs are formed trough the activation of aerosol particles called CCN (cloud condensation nuclei) described by the Köhler theory (Köhler, 1936). The number and distribution of the droplets activated during fog formation is determined by the aerosols particles properties and number and the ambient vapor supersaturation of the atmosphere. In the frame of the PreViBOSS project, an in-situ measurement platform of fog properties at ground level was deployed at SIRTA (Instrumented Site for Atmospheric Remote Sensing Research) during winter 2010 to 2013. Microphysics data supply a detailed characterization of number size spectrum from dry to wet aerosols particles and inform on the abilities of the aerosols particles to act as a CCN. 48 fog events have been studied. Supersaturation critical values and concentrations of CCN have been determined and linked to aerosols properties. The main impact of aerosols size distribution on activation have been pointed out. The study of droplets spectra evolution reveals the major physical processes into fogs and suggests that even if thermodynamic dominates the fog life cycle, activation process seems to have a significant effect. Large eddy simulation of fog run with Meso-NH model allow to explore precisely the interaction between fog physical processes and to quantify activation impact. Supersaturation modelling is a key point, a new pseudo-prognostic scheme (Thouron et al., 2012) is used. Confrontation between a detailed experimental study and three-dimensional fine scale simulation in LES provides an accurate investigation of the impact of activation process on fog life cycle.

  1. Properties of solar activity and ionosphere for solar cycle 25

    NASA Astrophysics Data System (ADS)

    Deminov, M. G.; Nepomnyashchaya, E. V.; Obridko, V. N.

    2016-11-01

    Based on the known forecast of solar cycle 25 amplitude ( Rz max ≈ 50), the first assessments of the shape and amplitude of this cycle in the index of solar activity F10.7 (the magnitude of solar radio flux at the 10.7 cm wavelength) are given. It has been found that ( F10.7)max ≈ 115, which means that it is the lowest solar cycle ever encountered in the history of regular ionospheric measurements. For this reason, many ionospheric parameters for cycle 25, including the F2-layer peak height and critical frequency ( hmF2 and foF2), will be extremely low. For example, at middle latitudes, typical foF2 values will not exceed 8-10 MHz, which makes ionospheric heating ineffective in the area of upper hybrid resonance at frequencies higher than 10 MHz. The density of the atmosphere will also be extremely low, which significantly extends the lifetime of low-orbit satellites. The probability of F-spread will be increased, especially during night hours.

  2. Methylation impact analysis of erythropoietin (EPO) Gene to hypoxia inducible factor-1α (HIF-1α) activity.

    PubMed

    Dewi, Firli Rahmah Primula; Fatchiyah, Fatchiyah

    2013-01-01

    Erythropoietin (EPO) is a glycoprotein hormone that play a role as key regulator in the production of red blood cells. The promoter region of EPO is methylated in normoxic (non-hypoxia) condition, but not in hypoxic condition. Methylation of the EPO enhancer region decline the transcription activity of EPO gene. The aim of this study is to investigate how different methylation percentage affected on the regulation and transcriptional activity of EPO gene. The DNA sequence of erythropoietin gene and protein sequence was retrieved from the sequence database of NCBI. DNA structure was constructed using 3D-DART web server and modeling structure of HIF1 predicted using SWISS-MODEL web server. Methylated DNA sequence of EPO gene using performed with YASARA View software and docking of EPO gene and transcription factor HIF1 analyzed by using HADDOCK webserver. Our result showed that binding energy in 46% methylated DNA was higher (-161,45 kcal/mol) than in unmethylated DNA (-194,16 kcal/mol) and 8% methylated DNA (-175,94 kcal/mol). So, we presume that a silencing mechanism of the Epo gene by methylation is correlated with the binding energy, which is required for interaction. A higher methylation percentage correlates with a higher binding energy which can cause an unstable interaction between DNA and transcription factor. In conclution, methylation of promoter and enhancer region of Epo gene leads to silencing.

  3. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    ERIC Educational Resources Information Center

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  4. SMYD3-mediated lysine methylation in the PH domain is critical for activation of AKT1

    PubMed Central

    Yoshioka, Yuichiro; Suzuki, Takehiro; Matsuo, Yo; Nakakido, Makoto; Tsurita, Giichiro; Simone, Cristiano; Watanabe, Toshiaki; Dohmae, Naoshi; Nakamura, Yusuke; Hamamoto, Ryuji

    2016-01-01

    AKT1 is a cytosolic serine/threonine kinase that is overexpressed in various types of cancer and has a central role in human tumorigenesis. Although it is known that AKT1 is post-translationally modified in various ways including phosphorylation and ubiquitination, methylation has not been reported so far. Here we demonstrate that the protein lysine methyltransferase SMYD3 methylates lysine 14 in the PH domain of AKT1 both in vitro and in vivo. Lysine 14-substituted AKT1 shows significantly lower levels of phosphorylation at threonine 308 than wild-type AKT1, and knockdown of SMYD3 as well as treatment with a SMYD3 inhibitor significantly attenuates this phosphorylation in cancer cells. Furthermore, substitution of lysine 14 diminishes the plasma membrane accumulation of AKT1, and cancer cells overexpressing lysine 14-substiuted AKT1 shows lower growth rate than those overexpressing wild-type AKT1. These results imply that SMYD3-mediated methylation of AKT1 at lysine 14 is essential for AKT1 activation and that SMYD3-mediated AKT1 methylation appears to be a good target for development of anti-cancer therapy. PMID:27626683

  5. Overcoming transcription activator-like effector (TALE) DNA binding domain sensitivity to cytosine methylation.

    PubMed

    Valton, Julien; Dupuy, Aurélie; Daboussi, Fayza; Thomas, Séverine; Maréchal, Alan; Macmaster, Rachel; Melliand, Kevin; Juillerat, Alexandre; Duchateau, Philippe

    2012-11-09

    Within the past 2 years, transcription activator-like effector (TALE) DNA binding domains have emerged as the new generation of engineerable platform for production of custom DNA binding domains. However, their recently described sensitivity to cytosine methylation represents a major bottleneck for genome engineering applications. Using a combination of biochemical, structural, and cellular approaches, we were able to identify the molecular basis of such sensitivity and propose a simple, drug-free, and universal method to overcome it.

  6. Evidence for Methyl-Compound-Activated Life in Coal Bed System 2 km Below Sea Floor

    NASA Astrophysics Data System (ADS)

    Trembath-reichert, E.; Morono, Y.; Dawson, K.; Wanger, G.; Bowles, M.; Heuer, V.; Hinrichs, K. U.; Inagaki, F.; Orphan, V. J.

    2014-12-01

    IODP Expedition 337 set the record for deepest marine scientific drilling down to 2.4 kmbsf. This cruise also had the unique opportunity to retrieve deep cores from the Shimokita coal bed system in Japan with the aseptic and anaerobic conditions necessary to look for deep life. Onboard scientists prepared nearly 1,700 microbiology samples shared among five different countries to study life in the deep biosphere. Samples spanned over 1 km in sampling depths and include representatives of shale, sandstone, and coal lithologies. Findings from previous IODP and deep mine expeditions suggest the genetic potential for methylotrophy in the deep subsurface, but it has yet to be observed in incubations. A subset of Expedition 337 anoxic incubations were prepared with a range of 13C-methyl substrates (methane, methylamine, and methanol) and maintained near in situ temperatures. To observe 13C methyl compound metabolism over time, we monitored the δ13C of the dissolved inorganic carbon (by-product of methyl compound metabolism) over a period of 1.5 years. Elemental analysis (EA), ion chromatograph (IC), 13C volatile fatty acid (VFA), and mineral-associated microscopy data were also collected to constrain initial and endpoint conditions in these incubations. Our geochemical evidence suggests that the coal horizon incubated with 13C-methane showed the highest activity of all methyl incubations. This provides the first known observation of methane-activated metabolism in the deep biosphere, and suggests there are not only active cells in the deeply buried terrigenous coal bed at Shimokita, but the presence of a microbial community activated by methylotrophic compounds.

  7. Observed Helicity of Active Regions in Solar Cycle 21

    NASA Technical Reports Server (NTRS)

    Hagyard, M. J.; Pevtsov, A. A.; Blehm, Z.; Smith, J. E.; Six, Frank (Technical Monitor)

    2003-01-01

    We report the results of a study of helicity in solar active regions during the peak of activity in solar cycle 21 from observations with the Marshall Space Flight Center's solar vector magnetograph. Using the force-free parameter alpha as the proxy for helicity, we calculated an average value of alpha for each of 60 active regions from a total of 449 vector magnetograms that were obtained during the period 1980 March to November. The signs of these average values of alpha were correlated with the latitude of the active regions to test the hemispheric rule of helicity that has been proposed for solar magnetic fields: negative helicity predominant in northern latitudes, positive in the southern ones. We have found that of the 60 regions that were observed, 30 obey the hemispheric rule and 30 do not.

  8. Ethanol Metabolism Activates Cell Cycle Checkpoint Kinase, Chk2

    PubMed Central

    Clemens, Dahn L.; Mahan Schneider, Katrina J.; Nuss, Robert F.

    2011-01-01

    Chronic ethanol abuse results in hepatocyte injury and impairs hepatocyte replication. We have previously shown that ethanol metabolism results in cell cycle arrest at the G2/M transition, which is partially mediated by inhibitory phosphorylation of the cyclin-dependent kinase, Cdc2. To further delineate the mechanisms by which ethanol metabolism mediates this G2/M arrest, we investigated the involvement of upstream regulators of Cdc2 activity. Cdc2 is activated by the phosphatase Cdc25C. The activity of Cdc25C can, in turn, be regulated by the checkpoint kinase, Chk2, which is regulated by the kinase ataxia telangiectasia mutated (ATM). To investigate the involvement of these regulators of Cdc2 activity, VA-13 cells, which are Hep G2 cells modified to efficiently express alcohol dehydrogenase, were cultured in the presence or absence of 25 mM ethanol. Immunoblots were performed to determine the effects of ethanol metabolism on the activation of Cdc25C, Chk2, and ATM. Ethanol metabolism increased the active forms of ATM, and Chk2, as well as the phosphorylated form of Cdc25C. Additionally, inhibition of ATM resulted in approximately 50% of the cells being rescued from the G2/M cell cycle arrest, and ameliorated the inhibitory phosphorylation of Cdc2. Our findings demonstrate that ethanol metabolism activates ATM. ATM can activate the checkpoint kinase Chk2, resulting in phosphorylation of Cdc25C, and ultimately in the accumulation of inactive Cdc2. This may, in part, explain the ethanol metabolism-mediated impairment in hepatocyte replication, which may be important in the initiation and progression of alcoholic liver injury. PMID:21924579

  9. Contribution of methylated exudate flavonoids to the anti-inflammatory activity of Grindelia robusta.

    PubMed

    Krenn, Liselotte; Wollenweber, Eckhard; Steyrleuthner, Katja; Görick, Cornelia; Melzig, Matthias F

    2009-07-01

    The flavonoid pattern of an acetonic extract of Grindelia robusta Nutt. was investigated in detail. The flavonoids were enriched by CC. In addition to twelve known methylated exudate flavonols four compounds were identified for the first time in G. robusta. Several substances of the flavonoid complex, among them the main compounds quercetin-3-methylether and 6-OH-kaempferol-3,6-dimethylether, were tested for their activity to inhibit neutrophil elastase. Quercetin-3-methylether was shown to be most active with an IC(50) of 19 microM, thus obviously contributing to the anti-inflammatory activity of the drug.

  10. Antimicrobial activity of fatty acid methyl esters of some members of Chenopodiaceae.

    PubMed

    Chandrasekaran, Manivachagam; Kannathasan, Krishnan; Venkatesalu, Venugopalan

    2008-01-01

    Fatty acid methyl ester (FAME) extracts of four halophytic plants, viz. Arthrocnemum indicum, Salicornia brachiata, Suaeda maritima and Suaeda monoica belonging to the family Chenopodiaceae, were prepared and their composition was analyzed by GC-MS. The FAME extracts were also screened for antibacterial and antifungal activities. The GC-MS analysis revealed the presence of more saturated fatty acids than unsaturated fatty acids. Among the fatty acids analyzed, the relative percentage of lauric acid was high in S. brachiata (61.85%). The FAME extract of S. brachiata showed the highest antibacterial and antifungal activities among the extracts tested. The other three extracts showed potent antibacterial and moderate anticandidal activities.

  11. Effects of solar cycle 24 activity on WAAS navigation

    NASA Astrophysics Data System (ADS)

    Datta-Barua, Seebany; Walter, Todd; Bust, Gary S.; Wanner, William

    2014-01-01

    This paper reviews the effects of geomagnetic activity of solar cycle 24 from 2011 through mid-2013 on the Federal Aviation Administration's Wide Area Augmentation System (WAAS) navigation service in the U.S., to identify (a) major impacts and their severity compared with the previous cycle and (b) effects in new service regions of North America added since last solar cycle. We examine two cases: a storm that reduced service coverage for several hours and ionospheric scintillation that led to anomalous receiver tracking. Using the 24-25 October 2011 storm as an example, we examine WAAS operational system coverage for the conterminous U.S. (CONUS). The WAAS algorithm upgrade to ionospheric estimation, in effect since late 2011, is able to mitigate the daytime coverage loss but not the nighttime loss. We correlate WAAS availability to maps of the storm plasma generated with the data assimilative model Ionospheric Data Assimilation 4-D, which show a local nighttime corotating persistent plume of plasma extending from Florida across central CONUS. We study the effect of scintillation on 9 October 2012 on the WAAS reference station at Fairbanks, Alaska. Data from a nearby scintillation monitor in Gakona and all-sky imaging of aurora at Poker Flat corroborate the event. Anomalous receiver processing triggered by scintillation reduces accuracy at Fairbanks for a few minutes. Users experiencing similar effects would have their confidence bounds inflated, possibly trading off service continuity for safety. The activity to date in solar cycle 24 has had minor effects on WAAS service coverage, mainly occurring in Alaska and Canada.

  12. Mayaro virus infection cycle relies on casein kinase 2 activity.

    PubMed

    Barroso, Madalena M S; Lima, Carla S; Silva-Neto, Mário A C; Da Poian, Andrea T

    2002-09-06

    Replication of Mayaro virus in Vero cells induces dramatic cytopathic effects and cell death. In this study, we have evaluated the role of casein kinase 2 (CK2) during Mayaro virus infection cycle. We found that CK2 was activated during the initial stages of infection ( approximately 36% after 4h). This activation was further confirmed when the enzyme was partially purified from the cellular lysate either by Mono Q 5/5Hr column or heparin-agarose column. Using this later column, we found that the elution profile of CK2 activity from infected cells was different from that obtained for control cell enzyme, suggesting a structural modification of CK2 after infection. Treatment of infected cells with a cell-permeable inhibitor of CK2, dichloro-1-(beta-D-ribofuranosyl)benzimidazole (DRB), abolished the cytopathic effect in a dose-dependent manner. Together this set of data demonstrates for the first time that CK2 activity in host cells is required in Mayaro virus infection cycle.

  13. Sunspot Activity Near Cycle Minimum and What it Might Suggest for Cycle 24, the Next Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2009-01-01

    In late 2008, 12-month moving averages of sunspot number, number of spotless days, number of groups, area of sunspots, and area per group were reflective of sunspot cycle minimum conditions for cycle 24, these values being of or near record value. The first spotless day occurred in January 2004 and the first new-cycle, high-latitude spot was reported in January 2008, although old-cycle, low-latitude spots have continued to be seen through April 2009, yielding an overlap of old and new cycle spots of at least 16 mo. New-cycle spots first became dominant over old-cycle spots in September 2008. The minimum value of the weighted mean latitude of sunspots occurred in May 2007, measuring 6.6 deg, and the minimum value of the highest-latitude spot followed in June 2007, measuring 11.7 deg. A cycle length of at least 150 mo is inferred for cycle 23, making it the longest cycle of the modern era. Based on both the maximum-minimum and amplitude-period relationships, cycle 24 is expected to be only of average to below-average size, peaking probably in late 2012 to early 2013, unless it proves to be a statistical outlier.

  14. Methyl supplementation attenuates cocaine-seeking behaviors and cocaine-induced c-Fos activation in a DNA methylation-dependent manner.

    PubMed

    Wright, Katherine N; Hollis, Fiona; Duclot, Florian; Dossat, Amanda M; Strong, Caroline E; Francis, T Chase; Mercer, Roger; Feng, Jian; Dietz, David M; Lobo, Mary Kay; Nestler, Eric J; Kabbaj, Mohamed

    2015-06-10

    Epigenetic mechanisms, such as histone modifications, regulate responsiveness to drugs of abuse, such as cocaine, but relatively little is known about the regulation of addictive-like behaviors by DNA methylation. To investigate the influence of DNA methylation on the locomotor-activating effects of cocaine and on drug-seeking behavior, rats receiving methyl supplementation via chronic l-methionine (MET) underwent either a sensitization regimen of intermittent cocaine injections or intravenous self-administration of cocaine, followed by cue-induced and drug-primed reinstatement. MET blocked sensitization to the locomotor-activating effects of cocaine and attenuated drug-primed reinstatement, with no effect on cue-induced reinstatement or sucrose self-administration and reinstatement. Furthermore, upregulation of DNA methyltransferase 3a and 3b and global DNA hypomethylation were observed in the nucleus accumbens core (NAc), but not in the medial prefrontal cortex (mPFC), of cocaine-pretreated rats. Glutamatergic projections from the mPFC to the NAc are critically involved in the regulation of cocaine-primed reinstatement, and activation of both brain regions is seen in human addicts when reexposed to the drug. When compared with vehicle-pretreated rats, the immediate early gene c-Fos (a marker of neuronal activation) was upregulated in the NAc and mPFC of cocaine-pretreated rats after cocaine-primed reinstatement, and chronic MET treatment blocked its induction in both regions. Cocaine-induced c-Fos expression in the NAc was associated with reduced methylation at CpG dinucleotides in the c-Fos gene promoter, effects reversed by MET treatment. Overall, these data suggest that drug-seeking behaviors are, in part, attributable to a DNA methylation-dependent process, likely occurring at specific gene loci (e.g., c-Fos) in the reward pathway.

  15. Methyl Supplementation Attenuates Cocaine-Seeking Behaviors and Cocaine-Induced c-Fos Activation in a DNA Methylation-Dependent Manner

    PubMed Central

    Wright, Katherine N.; Hollis, Fiona; Duclot, Florian; Dossat, Amanda M.; Strong, Caroline E.; Francis, T. Chase; Mercer, Roger; Feng, Jian; Dietz, David M.; Lobo, Mary Kay; Nestler, Eric J.

    2015-01-01

    Epigenetic mechanisms, such as histone modifications, regulate responsiveness to drugs of abuse, such as cocaine, but relatively little is known about the regulation of addictive-like behaviors by DNA methylation. To investigate the influence of DNA methylation on the locomotor-activating effects of cocaine and on drug-seeking behavior, rats receiving methyl supplementation via chronic l-methionine (MET) underwent either a sensitization regimen of intermittent cocaine injections or intravenous self-administration of cocaine, followed by cue-induced and drug-primed reinstatement. MET blocked sensitization to the locomotor-activating effects of cocaine and attenuated drug-primed reinstatement, with no effect on cue-induced reinstatement or sucrose self-administration and reinstatement. Furthermore, upregulation of DNA methyltransferase 3a and 3b and global DNA hypomethylation were observed in the nucleus accumbens core (NAc), but not in the medial prefrontal cortex (mPFC), of cocaine-pretreated rats. Glutamatergic projections from the mPFC to the NAc are critically involved in the regulation of cocaine-primed reinstatement, and activation of both brain regions is seen in human addicts when reexposed to the drug. When compared with vehicle-pretreated rats, the immediate early gene c-Fos (a marker of neuronal activation) was upregulated in the NAc and mPFC of cocaine-pretreated rats after cocaine-primed reinstatement, and chronic MET treatment blocked its induction in both regions. Cocaine-induced c-Fos expression in the NAc was associated with reduced methylation at CpG dinucleotides in the c-Fos gene promoter, effects reversed by MET treatment. Overall, these data suggest that drug-seeking behaviors are, in part, attributable to a DNA methylation-dependent process, likely occurring at specific gene loci (e.g., c-Fos) in the reward pathway. PMID:26063926

  16. In vitro methylation of nuclear respiratory factor-2 binding sites suppresses the promoter activity of the human TOMM70 gene.

    PubMed

    Blesa, José R; Hegde, Anita A; Hernández-Yago, José

    2008-12-31

    TOMM70 is a subunit of the outer mitochondrial membrane translocase that plays a major role as a receptor of hydrophobic preproteins targeted to mitochondria. We have previously reported that two binding sites for transcription factor NRF-2 in the promoter region of the human TOMM70 gene are essential in activating transcription (Blesa et al., Mitochondrion 2004; 3:251-59. Blesa et al., Biochem Cell Biol 2006; 84:813-22). This region contains thirteen CpG methylation sites, three of which occur in the sequence 5'-CCGG-3' that is specifically recognized by HpaII methylase which modifies the internal cytosine residue. Interestingly, each NRF-2 site contains one CCGG sequence, allowing specific methylation of the NRF-2 sites and, therefore, providing an ideal model to study how methylation of these sites affects promoter activity. In this paper we report that site-specific methylation of the NRF-2 binding sites in the TOMM70 promoter down-regulated expression of a luciferase reporter in HeLa S3 cells. Electrophoretic mobility shift assays confirmed abrogation of NRF-2 binding at the methylated sites. These results suggest that methylation of the TOMM70 promoter in mammalian cells may silence TOMM70 expression. However, studies of methylation degree on DNAs from different sources found no methylation in the promoter regions of TOMM70 and other TOMM/TIMM family genes. Thus, although in vitro methylation inactivates the expression of TOMM70, our results suggest that this is not the mechanism modulating its expression in vivo. Since a number of nuclear genes encoding mitochondrial translocases have NRF-2 binding sequences containing CpG methylation sites, a possible role of methylation as a regulatory mechanism of mitochondrial biogenesis can be ruled out.

  17. Acid activated montmorillonite as catalysts in methyl esterification reactions of lauric acid.

    PubMed

    Zatta, Leandro; Ramos, Luiz Pereira; Wypych, Fernando

    2012-01-01

    The catalytic activity of acid activated montmorillonite in the esterification of free fatty acids (FFA) is reported. Standard Montmorillonite (MMT) type STx-1 provided by the Clay Mineral Society repository was activated using phosphoric, nitric and sulphuric acids under different conditions and the resulting materials were characterized and evaluated as catalysts in the methyl esterification of lauric acid. Blank reactions carried out in the absence of any added catalyst presented conversions of 32.64, 69.79 and 79.23%, for alcohol:lauric acid molar ratios of 60:1, 12:1 and 6:1, respectively. In the presence of the untreated clay and using molar ratios of 12:1 and 6:1 with 12% of catalyst, conversions of 70.92 and 82.30% were obtained, respectively. For the acid activated clays, conversions up to 93.08% of lauric acid to methyl laurate were obtained, much higher than those observed for the thermal conversion or using untreated montmorillonite. Relative good correlations were observed between the catalytic activity and the development of acid sites and textural properties of the resulting materials. Therefore, a simple acid activation was able to improve the catalytic activity and produce clay catalysts that are environmental friendly, cost effective, noncorrosive and reusable.

  18. EEG activity during estral cycle in the rat.

    PubMed

    Corsi-Cabrera, M; Juárez, J; Ponce-de-León, M; Ramos, J; Velázquez, P N

    1992-10-01

    EEG activity was recorded from right and left parietal cortex in adult female rats daily during 6 days. Immediately after EEG recording vaginal smears were taken and were microscopically analyzed to determine the estral stage. Absolute and relative powers and interhemispheric correlation of EEG activity were calculated and compared between estral stages. Interhemispheric correlation was significantly lower during diestrous as compared to proestrous and estrous. Absolute and relative powers did not show significant differences between estral stages. Absolute powers of alpha1, alpha2, beta1 and beta2 bands were significantly higher at the right parietal cortex. Comparisons of the same EEG records with estral stages randomly grouped showed no significant differences for any of the EEG parameters. EEG activity is a sensitive tool to study functional changes related to the estral cycle.

  19. Promoter Methylation Pattern Controls Corticotropin Releasing Hormone Gene Activity in Human Trophoblasts

    PubMed Central

    Pan, Xin; Bowman, Maria; Scott, Rodney J.; Fitter, John; Smith, Roger

    2017-01-01

    Placental CRH production increases with advancing pregnancy in women and its course predicts gestational length. We hypothesized that CRH gene expression in the placenta is epigenetically controlled setting gestational trajectories characteristic of normal and pathological pregnancies. Here we determined histone modification and DNA methylation levels and DNA methylation patterns at the CRH promoter in primary trophoblast cultures by chromatin immunoprecipitation combined with clonal bisulfite sequencing and identified the transcriptionally active epialleles that associate with particular histone modifications and transcription factors during syncytialisation and cAMP-stimulation. CRH gene expression increased during syncytial differentiation and cAMP stimulation, which was associated with increased activating and decreased repressive histone modification levels at the promoter. DNA methylation levels remained unchanged. The nine CpGs of the CRH proximal promoter were partially and allele-independently methylated displaying many (>100) epialleles. RNA-polymerase-II (Pol-II) bound only to three particular epialleles in cAMP-stimulated cells, while phospho-cAMP response element-binding protein (pCREB) bound to only one epiallele, which was different from those selected by Pol-II. Binding of TATA-binding protein increased during syncytial differentiation preferentially at epialleles compatible with Pol-II and pCREB binding. Histone-3 acetylation was detected only at epialleles targeted by Pol-II and pCREB, while gene activating histone-4 acetylation and histone-3-lysine-4 trimethylation occurred at CRH epialleles not associated with Pol-II or pCREB. The suppressive histone-3-lysine-27 trimethyl and–lysine-9 trimethyl modifications showed little or no epiallele preference. The epiallele selectivity of activating histone modifications and transcription factor binding demonstrates the epigenetic and functional diversity of the CRH gene in trophoblasts, which is

  20. A new simple dynamo model for solar activity cycle

    NASA Astrophysics Data System (ADS)

    Yokoi, Nobumitsu; Schmitt, Dieter

    2015-04-01

    The solar magnetic activity cycle has been investigated in an elaborated manner with several types of dynamo models [1]. In most of the current mean-field approaches, the inhomogeneity of the large-scale flow is treated as an essential ingredient in the mean magnetic field equation whereas it is completely neglected in the turbulence equation. In this work, a new simple model for the solar activity cycle is proposed. The present model differs from the previous ones mainly in two points. First, in addition to the helicity coefficient α, we consider a term related to the cross helicity, which represents the effect of the inhomogeneous mean flow, in the turbulent electromotive force [2, 3]. Second, this transport coefficient (γ) is not treated as an adjustable parameter, but the evolution equation for γ is simultaneously solved. The basic scenario for the solar activity cycle in this approach is as follows: The toroidal field is induced by the toroidal rotation in mediation by the turbulent cross helicity. Then due to the α or helicity effect, the poloidal field is generated from the toroidal field. The poloidal field induced by the α effect produces a turbulent cross helicity whose sign is opposite to the original one (negative cross-helicity production). The cross helicity with this opposite sign induces a reversed toroidal field. Results of the eigenvalue analysis of the model equations are shown, which confirm the above scenario. References [1] Charbonneau, Living Rev. Solar Phys. 7, 3 (2010). [2] Yoshizawa, A. Phys. Fluids B 2, 1589 (1990). [3] Yokoi, N. Geophys. Astrophys. Fluid Dyn. 107, 114 (2013).

  1. Sources of solar wind over the solar activity cycle

    PubMed Central

    Poletto, Giannina

    2012-01-01

    Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. PMID:25685421

  2. Sources of solar wind over the solar activity cycle.

    PubMed

    Poletto, Giannina

    2013-05-01

    Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review.

  3. Seasonal cycles in testicular activity in the frog, Rana perezi.

    PubMed

    Delgado, M J; Gutiérrez, P; Alonso-Bedate, M

    1989-01-01

    Studies of seasonal testicular cycle based on spermatogenetic activity and direct measurement of plasma testosterone were made in male frog Rana perezi obtained from its natural biotope in the Iberian Peninsula. Testosterone plasma level was determined by radioimmunoassay and exhibited notable differences according to season: plasma testosterone was lowest (less than 0.5 ng/ml) in summer and then increased progressively to reach a peak in spring (3-4 ng/ml), coincident with mating. After spermiation, when an increase in temperature and photoperiod in the natural habitat occurs, levels decline. Fat bodies also show a pronounced seasonal cycle with total regression following breeding and maximal development in winter. However, testicular weight was independent of seasons, and no significant change was observed throughout the year. Histological evidence indicates that although cell nests of different types are present every month of the year, the most important spermatogenetic activity is initiated in summer. The possible relationship between spermatogenetic activity and testosterone production and the importance of environmental factors as synchronizers of seasonal reproduction are discussed.

  4. Synthesis of [3-N-(11) C-methyl]temozolomide via in situ activation of 3-N-hydroxymethyl temozolomide and alkylation with [(11) C]methyl iodide.

    PubMed

    Eriksson, Jonas; Van Kooij, Rolph; Schuit, Robert C; Froklage, Femke E; Reijneveld, Jaap C; Hendrikse, N Harry; Windhorst, Albert D

    2015-03-01

    Temozolomide is a chemotherapeutic drug that is mainly used in the treatment of primary glioblastoma multiforme and recurrent high-grade glioma. Here, we report an efficient good manufacturing practice compliant method for the synthesis of [3-N-(11) C-methyl]temozolomide from 3-N-hydroxymethyl temozolomide that cleaves off formaldehyde in situ and becomes activated towards alkylation with [(11) C]methyl iodide. The labelling method was developed for an on-going patient study in which the predictive value of [3-N-(11) C-methyl]temozolomide and positron emission tomography on the outcome of temozolomide treatment is being investigated. The precursor was reacted with [(11) C]methyl iodide in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene in acetonitrile, heated at stepwise increasing temperature. Purification by semipreparative HPLC with pharmaceutical grade eluent and filtration gave approximately 10 mL sterile product solution ready for injection containing 1.55 ± 0.38 GBq (n = 5), the specific activity was 88 ± 25 GBq/µmol and the radiochemical purity was 98.5 ± 1.9%. (13) C-NMR spectroscopy confirmed the labelled position after colabelling with (11) C and (13) C.

  5. DNA Methylation Affects the Efficiency of Transcription Activator-Like Effector Nucleases-Mediated Genome Editing in Rice

    PubMed Central

    Kaya, Hidetaka; Numa, Hisataka; Nishizawa-Yokoi, Ayako; Toki, Seiichi; Habu, Yoshiki

    2017-01-01

    Genome editing in plants becomes popular since the advent of sequence-specific nucleases (SSNs) that are simple to set up and efficient in various plant species. Although transcription activator-like effector nucleases (TALENs) are one of the most prevalent SSNs and have a potential to provide higher target specificity by their dimeric property, TALENs are sensitive to methylated cytosines that are present not only in transposons but also in active genes in plants. In mammalian cells, the methylation sensitivity of TALENs could be overcome by using a base-recognition module (N∗) that has a higher affinity to methylated cytosine. In contrast to mammals, plants carry DNA methylation at all cytosine contexts (CG, CHG, and CHH, where H represents A, C, or T) with various degrees and effectiveness of N∗ module in genome editing in plants has not been explored. In this study, we designed sets of TALENs with or without N∗ modules and examined their efficiency in genome editing of methylated regions in rice. Although improvement in genome editing efficiency was observed with N∗-TALENs designed to a stably methylated target, another target carrying cytosines with various levels of methylation showed resistance to both normal and N∗-TALENs. The results suggest that variability of cytosine methylation in target regions is an additional factor affecting the genome editing efficiency of TALENs. PMID:28348570

  6. CDK1-Cyclin B1 Activates RNMT, Coordinating mRNA Cap Methylation with G1 Phase Transcription

    PubMed Central

    Aregger, Michael; Kaskar, Aneesa; Varshney, Dhaval; Fernandez-Sanchez, Maria Elena; Inesta-Vaquera, Francisco A.; Weidlich, Simone; Cowling, Victoria H.

    2016-01-01

    Summary The creation of translation-competent mRNA is dependent on RNA polymerase II transcripts being modified by addition of the 7-methylguanosine (m7G) cap. The factors that mediate splicing, nuclear export, and translation initiation are recruited to the transcript via the cap. The cap structure is formed by several activities and completed by RNMT (RNA guanine-7 methyltransferase), which catalyzes N7 methylation of the cap guanosine. We report that CDK1-cyclin B1 phosphorylates the RNMT regulatory domain on T77 during G2/M phase of the cell cycle. RNMT T77 phosphorylation activates the enzyme both directly and indirectly by inhibiting interaction with KPNA2, an RNMT inhibitor. RNMT T77 phosphorylation results in elevated m7G cap methyltransferase activity at the beginning of G1 phase, coordinating mRNA capping with the burst of transcription that occurs following nuclear envelope reformation. RNMT T77 phosphorylation is required for the production of cohort of proteins, and inhibiting T77 phosphorylation reduces the cell proliferation rate. PMID:26942677

  7. Characteristics of the 23 Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Tamara

    The aim of the present study is to search for special features of the 23-d cycle of solar activity. We present results of our analysis of spectra of sunspot number W for the time intervals of spaced measurements 1964-1997 and 1996-2005 and of the Interplanetary Magnetic Field (IMF), the solar wind velocity (V) calculated on the basis of measurements near the Earth's orbit for the period 1964-1997. A method of non-linear spectral analysis named by us the Method of Global Minimum (MGM) is used. MGM allows self-consistentidentification of trends from data and non-stationary sinusoids and estimation of statistical significance of spectral components. The IMF and W spectra for the period 1964-1997 both show the solar cycle at T=10.8 yr and its higher harmonics. But spectrum of sunspot number W for the period 1996-2005 (time interval of the 23-d cycle) has not spectral component at T=10.8 yr (at confidence statistical level 95%); however, this spectrum has higher harmonics of the 10.8-yr cycle (such as sinusoid with T=146.2 day). The most powerful spectral line from the spectrum (1996-2005) has period T=16.56 yr. We show that tide forces of the planets can be a cause of periodical changes in the analyzed data. Periods of perturbed tide forces of external planets and their higher harmonics (connected with motion of the Sun relative to the mass center of the solar system) are detected in the spectra. In particular, all periods from the spectrum of W for the period 1996-2005 can be interpreted as periods of perturbed tide force of a system: Sun - a pair Jupiter-Uranus: T=16.56 yr is period of perturbed tide force of pair Jupiter-Uranus (1st planet determines shift of mass center of the Sun relative to the mass center of a system the Sunthe 1st planet; the 2nd planet determines perturbed tide force acting on the Sun). The fact that spectrum of W for the period 1996-2005 has the most power spectral components at T=16.56 and T=1.83 yr (9 harmonics of the 16.56-yr cycle

  8. Cyclical DNA Methylation and Histone Changes Are Induced by LPS to Activate COX-2 in Human Intestinal Epithelial Cells

    PubMed Central

    Brancaccio, Mariarita; Coretti, Lorena; Florio, Ermanno; Pezone, Antonio; Calabrò, Viola; Falco, Geppino; Keller, Simona; Lembo, Francesca; Avvedimento, Vittorio Enrico; Chiariotti, Lorenzo

    2016-01-01

    Bacterial lipopolysaccharide (LPS) induces release of inflammatory mediators both in immune and epithelial cells. We investigated whether changes of epigenetic marks, including selected histone modification and DNA methylation, may drive or accompany the activation of COX-2 gene in HT-29 human intestinal epithelial cells upon exposure to LPS. Here we describe cyclical histone acetylation (H3), methylation (H3K4, H3K9, H3K27) and DNA methylation changes occurring at COX-2 gene promoter overtime after LPS stimulation. Histone K27 methylation changes are carried out by the H3 demethylase JMJD3 and are essential for COX-2 induction by LPS. The changes of the histone code are associated with cyclical methylation signatures at the promoter and gene body of COX-2 gene. PMID:27253528

  9. Design, synthesis and antimycobacterial activities of 1-methyl-2-alkenyl-4(1H)-quinolones

    PubMed Central

    Wube, Abraham A.; Hüfner, Antje; Thomaschitz, Christina; Blunder, Martina; Kollroser, Manfred; Bauer, Rudolf; Bucar, Franz

    2011-01-01

    A series of 23 new 1-methyl-2-alkenyl-4(1H)quinolones have been synthesized and evaluated in vitro for their antimycobacterial activities against fast growing species of mycobacteria, such as Mycobacterium fortuitum, M. smegmatis and M. phlei. The compounds displayed good to excellent inhibition of the growth of the mycobacterial test strains with improved antimycobacterial activity compared to the hit compound, evocarpine. The most active compounds, which possessed chain length of 11–13 carbons at position-2 displayed potent inhibitory effects with an MIC value of 1.0 mg/L. In a human diploid embryonic lung cell line, MRC-5 cytotoxicity assay, the alkaloids showed weak to moderate cytotoxic activity. Biological evaluation of these evocarpine analogues on the less pathogenic fast growing strains of mycobacteria showed an interesting antimycobacterial profile and provided significant insight into the structure–activity relationships. PMID:21106378

  10. Sphaeropsidones, phytotoxic dimedone methyl ethers produced by Diplodia cupressi: a structure-activity relationship study.

    PubMed

    Evidente, Antonio; Maddau, Lucia; Scanu, Bruno; Andolfi, Anna; Masi, Marco; Motta, Andrea; Tuzi, Angela

    2011-04-25

    Sphaeropsidone and episphaeropsidone are two phytotoxic dimedone methyl ethers produced by Diplodia cupressi, the causal agent of a canker disease of cypress in the Mediterranean area. In this study, eight derivatives obtained by chemical modifications and two natural analogues were assayed for phytotoxic and antifungal activities, and a structure-activity relationship was examined. Each compound was tested on nonhost plants and on five fungal pathogenic species belonging to the genus Phytophthora. The results provide insights into structure-activity relationships within these compounds. It was found that the hydroxy group at C-5, the absolute C-5 configuration, the epoxy group, and the C-2 carbonyl group appear to be structural features important in conferring biological activity. The conversion of sphaeropsidone into the corresponding 1,4-dione derivative led to a compound showing greater antifungal activity than its precursor. This finding could be useful in devising new natural fungicides for practical application in agriculture.

  11. Methods for Activity Analysis of the Proteins that Regulate Histone Methylation

    PubMed Central

    Quinn, Amy M; Simeonov, Anton

    2011-01-01

    The enzymes that regulate histone methylation states and the protein domains that recognize methylated histone residues have been implicated in a number of human diseases, including cancer, as a result of their ability to affect transcriptional changes by altering chromatin structure. These proteins are recognized as potential therapeutic targets for the treatment of diseases associated with epigenetic disruption; however, few inhibitors of their activity have been identified. The majority of histone demethylase and methyltransferase enzyme inhibitors have been discovered on the basis of their structural similarity to substrates or known inhibitors of enzymes with analogous mechanisms. The general lack of potency and specificity of these compounds indicates that novel chemotypes are needed to address the large number of recently discovered histone-modifying enzymes. High-throughput screening (HTS) allows rapid testing of chemically diverse small molecule libraries, provided assays amenable to HTS exist. Here we review the biochemical and cellular assays available for testing the proteins and enzymes that regulate histone methylation. Progress in the development of high-throughput, sensitive, and robust assays will enable discovery of small molecules for epigenetic therapy. PMID:21966349

  12. Activation of endocrine-related gene expression in placental choriocarcinoma cell lines following DNA methylation knock-down.

    PubMed

    Hogg, K; Robinson, W P; Beristain, A G

    2014-07-01

    Increasingly, placental DNA methylation is assessed as a factor in pregnancy-related complications, yet the transcriptional impact of such findings is not always clear. Using a proliferative in vitro placental model, the effect of DNA methylation loss on gene activation was evaluated at a number of genes selected for being differentially methylated in pre-eclampsia-associated placentae in vivo. We aimed to determine whether reduced DNA methylation at specific loci was associated with transcriptional changes at the corresponding gene, thus providing mechanistic underpinnings for previous clinical findings and to assess the degree of transcriptional response amongst our candidate genes. BeWo and JEG3 choriocarcinoma cells were exposed to 1 μM 5-Aza-2'-deoxycytidine (5-Aza-CdR) or vehicle control for 48 h, and re-plated and cultured for a further 72 h in normal media before cells were harvested for RNA and DNA. Bisulphite pyrosequencing confirmed that DNA methylation was reduced by ∼30-50% points at the selected loci studied in both cell lines. Gene activation, measured by qRT-PCR, was highly variable and transcript specific, indicating differential sensitivity to DNA methylation. Most notably, loss of DNA methylation at the leptin (LEP) promoter corresponded to a 200-fold and 40-fold increase in LEP expression in BeWo and JEG3 cells, respectively (P < 0.01). Transcripts of steroidogenic pathway enzymes CYP11A1 and HSD3B1 were up-regulated ∼40-fold in response to 5-Aza-CdR exposure in BeWo cells (P < 0.01). Other transcripts, including aromatase (CYP19), HSD11B2, inhibin (INHBA) and glucocorticoid receptor (NR3C1) were more moderately, although significantly, affected by loss of associated DNA methylation. These data present a mixed effect of DNA methylation changes at selected loci supporting cautionary interpretation of DNA methylation results in the absence of functional data.

  13. Correlation between quantified promoter methylation and enzymatic activity of O6-methylguanine-DNA methyltransferase in glioblastomas.

    PubMed

    Kishida, Yugo; Natsume, Atsushi; Toda, Hiroshi; Toi, Yuki; Motomura, Kazuya; Koyama, Hiroko; Matsuda, Keiji; Nakayama, Osamu; Sato, Makoto; Suzuki, Masaaki; Kondo, Yutaka; Wakabayashi, Toshihiko

    2012-04-01

    The DNA repair protein O (6)-methylguanine-DNA methyltransferase (MGMT, AGT) is a determinant of the resistance of tumor cells to alkylating anticancer agents that target the O(6) position of guanine. MGMT promoter methylation in tumors is regarded as the most common predictor of the responsiveness of glioblastoma to alkylating agents. However, MGMT promoter methylation status has been investigated mainly by methylation-specific PCR, which is a qualitative and subjective assay. In addition, the actual enzymatic activities associated with the methylation status of MGMT have not been explored. In the present study, MGMT promoter methylation in glioblastomas was quantified by bisulfite pyrosequencing, and its correlation with enzymatic activity was determined using a novel quantitative assay for studying the functional activity of MGMT. MGMT enzymatic activity was assessed using fluorometrically labeled oligonucleotide substrates containing MGMT-specific DNA lesions and capillary electrophoresis to detect and quantify these lesions. In comparison with existing traditional assays, this assay was equally sensitive but less time consuming and easier to perform. MGMT promoter methylation was assessed in 41 glioblastomas by bisulfite pyrosequencing, and five samples with different values were chosen for comparison with enzymatic assays. Bisulfite pyrosequencing using primers designed to work in the upstream promoter regions of MGMT demonstrated high quantitative capability and reproducibility in triplicate measurements. In comparative studies, MGMT promoter methylation values obtained by bisulfite pyrosequencing were inversely proportional to the measured enzymatic activity. The present results indicate that the quantification of MGMT methylation by bisulfite pyrosequencing represents its enzymatic activity and thus, its therapeutic responsiveness to alkylating agents.

  14. No link between the solar activity cycle and the diameter

    NASA Astrophysics Data System (ADS)

    Dame, L.; Cugnet, D.

    We do not understand the physical mechanisms responsible for the solar irradiance cycle. Measurements of small variations in the solar diameter could have been a critical probe of the Sun 's interior stratification, telling us how and where the solar luminosity is gated or stored. We have reanalyzed the 7 years of filtregrams data (150 000 photograms and magnetograms) of the SOHO/MDI experiment. We used the maximum possible sampling compatible with full frame recording, carefully avoiding any suspicious filtregram. Going further than the previous analysis of 2 years of data by Emilio et al. (Ap. J. 543,1007, 2000), we better corrected for changes in optical aberrations and, along Turmon et al. (Ap. J., 568, 396, 2002), we reduced radius measurement errors by identifying active regions and avoiding radius measurements herein. We found that, within the limit of our noise level uncertainties (2 mas), the solar diameter could be constant over the half cycle investigated. Our results confirm the recent reanalysis of the 7 years of MDI data made by Antia (Ap. J. 590, 567, 2003), with a completely different method since using the ultra-precise frequency variation of the f-modes (fundamental modes linked to the diameter). He found (carefully removing the yearly Earth induced variations and avoiding the SOHO data gap of 1999) that the diameter is constant over the half solar cycle (radius variation are less than 0.6 km, 0.8 mas - nothing over noise level). Along Antia, we can conclude that: "If a careful analysis is performed, then it turns out that there is no evidence for any variation in the solar radius." There were no theoretical reasons for large solar radius variations and there is no observational evidence for them with consistent space observations. If changes exit, they are to be very small.

  15. Effects of Low Activity Solar Cycle on Orbital Debris Lifetime

    NASA Technical Reports Server (NTRS)

    Cable, Samual B.; Sutton, Eric K.; Lin, chin S.; Liou, J.-C.

    2011-01-01

    Long duration of low solar activity in the last solar minimum has an undesirable consequence of extending the lifetime of orbital debris. The AFRL TacSat-2 satellite decommissioned in 2008 has finally re-entered into the atmosphere on February 5th after more than one year overdue. Concerning its demise we have monitored its orbital decay and monthly forecasted Tacsat-2 re-entry since September 2010 by using the Orbital Element Prediction (OEP) model developed by the AFRL Orbital Drag Environment program. The model combines estimates of future solar activity with neutral density models, drag coefficient models, and an orbit propagator to predict satellite lifetime. We run the OEP model with solar indices forecast by the NASA Marshall Solar Activity Future Estimation model, and neutral density forecast by the MSIS-00 neutral density model. Based on the two line elements in 2010 up to mid September, we estimated at a 50% confidence level TacSat-2's re-entry time to be in early February 2011, which turned out to be in good agreement with Tacsat-2's actual re-entry date. The potential space weather effects of the coming low activity solar cycle on satellite lifetime and orbital debris population are examined. The NASA long-term orbital debris evolutionary model, LEGEND, is used to quantify the effects of solar flux on the orbital debris population in the 200-600 km altitude environment. The results are discussed for developing satellite orbital drag application product.

  16. Intertwined arbovirus transmission activity: reassessing the transmission cycle paradigm

    PubMed Central

    Diaz, Luis A.; Flores, Fernando S.; Quaglia, Agustín; Contigiani, Marta S.

    2013-01-01

    Arboviruses are emerging/reemerging infectious agents worldwide. The factors within this scenario include vector and host population fluctuations, climatic changes, anthropogenic activities that disturb ecosystems, an increase in international flights, human mobility, and genetic mutations that allow spill-over phenomenon. Arboviruses are maintained by biologic transmission among vectors and hosts. Sometimes this biological transmission is specific and includes one vector and host species such as Chikungunya (CHIKV), Dengue (DENV), and urban Yellow Fever (YFV). However, most of the arboviruses are generalist and they use many vectors and hosts species. From this perspective, arboviruses are maintained through a transmission network rather than a transmission cycle. This allows us to understand the complexity and dynamics of the transmission and maintenance of arboviruses in the ecosystems. The old perspective that arboviruses are maintained in close and stable transmission cycles should be modified by a new more integrative and dynamic idea, representing the real scenario where biological interactions have a much broader representation, indicating the constant adaptability of the biological entities. PMID:23335900

  17. Global changes in biogeochemical cycles in response to human activities

    NASA Technical Reports Server (NTRS)

    Moore, Berrien, III; Melillo, Jerry

    1994-01-01

    The main objective of our research was to characterize biogeochemical cycles at continental and global scales in both terrestrial and aquatic ecosystems. This characterization applied to both natural ecosystems and those disturbed by human activity. The primary elements of interest were carbon and nitrogen and the analysis sought to quantify standing stocks and dynamic cycling processes. The translocation of major nutrients from the terrestrial landscape to the atmosphere (via trace gases) and to fluvial systems (via leaching, erosional losses, and point source pollution) were of particular importance to this study. Our aim was to develop the first generation of Earth System Models. Our research was organized around the construction and testing of component biogeochemical models which treated terrestrial ecosystem processes, aquatic nutrient transport through drainage basins, and trace gas exchanges at the continental and global scale. A suite of three complementary models were defined within this construct. The models were organized to operate at a 1/2 degree latitude by longitude level of spatial resolution and to execute at a monthly time step. This discretization afforded us the opportunity to understand the dynamics of the biosphere down to subregional scales, while simultaneously placing these dynamics into a global context.

  18. Enhancement of ribozyme catalytic activity by a contiguous oligodeoxynucleotide (facilitator) and by 2'-O-methylation.

    PubMed Central

    Goodchild, J

    1992-01-01

    RNA catalysts (ribozymes) designed to cleave sequences unique to viral RNA's might be developed as therapeutics. For this purpose, they would require high catalytic efficiency and resistance to nucleases. Reported here are two approaches that can be used in combination to improve these properties. First, catalytic efficiency can be improved by oligonucleotides (facilitators) that bind to the substrate contiguously with the 3'-end of the ribozyme. Second, 2'-O-methylation of flanking sequences of the ribozyme increases catalytic activity as well as resistance to nucleases. In combination with a facilitator oligodeoxynucleotide, the cleavage rate was increased 20 fold over that of the unmodified ribozyme. Images PMID:1383929

  19. Spectroscopic and XRD characterisation of zeolite catalysts active for the oxidative methylation of benzene with methane.

    PubMed

    Adebajo, Moses O; Long, Mervyn A; Frost, Ray L

    2004-03-01

    The benzene methylation with methane over zeolite catalysts was previously shown in our laboratory to require the presence of oxygen. Thus, a two-step mechanism involving the intermediate formation of methanol by partial oxidation of methane followed by the methylation of benzene with methanol in the second step, was postulated. This paper now reports the results of the characterisation of the zeolite catalysts used for the oxidative benzene methylation reaction in order to provide some information about their composition, structure, properties and their behaviour before and after the reaction. The catalysts were characterised by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray fluorescence (XRF), FT-IR and solid state NMR. XRD results indicate that the crystalline structures of all the ZSM-5 and H-beta catalysts remained unchanged after batch reaction of benzene with methane over the catalysts in agreement with the observation that the catalysts recovered from the reactor could be reused without loss of activity. Elemental analyses and FT-IR data show that as the level of metal ion exchange increases, the Brönsted acid concentration decreases but this metal ion exchange does not totally remove Brönsted acidity. FT-IR results further show that only a small amount of acid sites is actually necessary for a catalyst to be active since used catalysts containing highly reduced Brönsted acidity are found to be reusable without any loss of their activity. 29Si and 27Al magic angle spinning (MAS) NMR together with FT-IR spectra also show that all the active zeolites catalysts contain some extra-framework octahedral aluminium in addition to the normal tetrahedral framework aluminium. The presence of this extra-lattice aluminium does not, however, have any adverse effect on the crystallinity of the catalysts both before and after oxidative benzene methylation reaction. There appears also to be no significant dealumination

  20. Spectroscopic and XRD characterisation of zeolite catalysts active for the oxidative methylation of benzene with methane

    NASA Astrophysics Data System (ADS)

    Adebajo, Moses O.; Long, Mervyn A.; Frost, Ray L.

    2004-03-01

    The benzene methylation with methane over zeolite catalysts was previously shown in our laboratory to require the presence of oxygen. Thus, a two-step mechanism involving the intermediate formation of methanol by partial oxidation of methane followed by the methylation of benzene with methanol in the second step, was postulated. This paper now reports the results of the characterisation of the zeolite catalysts used for the oxidative benzene methylation reaction in order to provide some information about their composition, structure, properties and their behaviour before and after the reaction. The catalysts were characterised by X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray fluorescence (XRF), FT-IR and solid state NMR. XRD results indicate that the crystalline structures of all the ZSM-5 and H-beta catalysts remained unchanged after batch reaction of benzene with methane over the catalysts in agreement with the observation that the catalysts recovered from the reactor could be reused without loss of activity. Elemental analyses and FT-IR data show that as the level of metal ion exchange increases, the Brönsted acid concentration decreases but this metal ion exchange does not totally remove Brönsted acidity. FT-IR results further show that only a small amount of acid sites is actually necessary for a catalyst to be active since used catalysts containing highly reduced Brönsted acidity are found to be reusable without any loss of their activity. 29Si and 27Al magic angle spinning (MAS) NMR together with FT-IR spectra also show that all the active zeolites catalysts contain some extra-framework octahedral aluminium in addition to the normal tetrahedral framework aluminium. The presence of this extra-lattice aluminium does not, however, have any adverse effect on the crystallinity of the catalysts both before and after oxidative benzene methylation reaction. There appears also to be no significant dealumination

  1. Synthesis of derivatives of methyl rosmarinate and their inhibitory activities against matrix metalloproteinase-1 (MMP-1).

    PubMed

    Yuan, Hu; Lu, Weiqiang; Wang, Liyan; Shan, Lei; Li, Honglin; Huang, Jin; Sun, Qingyan; Zhang, Weidong

    2013-04-01

    A series of MMP-1 inhibitors have been identified based upon a methyl rosmarinate scaffold using structure-based drug design methods. The best compound in the series showed an IC50 value of 0.4 μM. A docking study was conducted for compound (S)-10n in order to investigate its binding interactions with MMP-1. The structure-activity relationships (SAR) were also briefly discussed. Useful SAR was established which provides important guidelines for the design of future generations of potent inhibitors against MMP-1.

  2. Arginine methylation promotes translation repression activity of eIF4G-binding protein, Scd6

    PubMed Central

    Poornima, Gopalakrishna; Shah, Shanaya; Vignesh, Venkadasubramanian; Parker, Roy; Rajyaguru, Purusharth I.

    2016-01-01

    Regulation of translation plays a critical role in determining mRNA fate. A new role was recently reported for a subset of RGG-motif proteins in repressing translation initiation by binding eIF4G1. However the signaling mechanism(s) that leads to spatial and temporal regulation of repression activity of RGG-motif proteins remains unknown. Here we report the role of arginine methylation in regulation of repression activity of Scd6, a conserved RGG-motif protein. We demonstrate that Scd6 gets arginine methylated at its RGG-motif and Hmt1 plays an important role in its methylation. We identify specific methylated arginine residues in the Scd6 RGG-motif in vivo. We provide evidence that methylation augments Scd6 repression activity. Arginine methylation defective (AMD) mutant of Scd6 rescues the growth defect caused by overexpression of Scd6, a feature of translation repressors in general. Live-cell imaging of the AMD mutant revealed that it is defective in inducing formation of stress granules. Live-cell imaging and pull-down results indicate that it fails to bind eIF4G1 efficiently. Consistent with these results, a strain lacking Hmt1 is also defective in Scd6-eIF4G1 interaction. Our results establish that arginine methylation augments Scd6 repression activity by promoting eIF4G1-binding. We propose that arginine methylation of translation repressors with RGG-motif could be a general modulator of their repression activity. PMID:27613419

  3. Activation induced deaminase mutational signature overlaps with CpG methylation sites in follicular lymphoma and other cancers

    PubMed Central

    Rogozin, Igor B.; Lada, Artem G.; Goncearenco, Alexander; Green, Michael R.; De, Subhajyoti; Nudelman, German; Panchenko, Anna R.; Koonin, Eugene V.; Pavlov, Youri I.

    2016-01-01

    Follicular lymphoma (FL) is an uncurable cancer characterized by progressive severity of relapses. We analyzed sequence context specificity of mutations in the B cells from a large cohort of FL patients. We revealed substantial excess of mutations within a novel hybrid nucleotide motif: the signature of somatic hypermutation (SHM) enzyme, Activation Induced Deaminase (AID), which overlaps the CpG methylation site. This finding implies that in FL the SHM machinery acts at genomic sites containing methylated cytosine. We identified the prevalence of this hybrid mutational signature in many other types of human cancer, suggesting that AID-mediated, CpG-methylation dependent mutagenesis is a common feature of tumorigenesis. PMID:27924834

  4. Laser Irradiation-Induced DNA Methylation Changes Are Heritable and Accompanied with Transpositional Activation of mPing in Rice

    PubMed Central

    Li, Siyuan; Xia, Qiong; Wang, Fang; Yu, Xiaoming; Ma, Jian; Kou, Hongping; Lin, Xiuyun; Gao, Xiang; Liu, Bao

    2017-01-01

    DNA methylation is an integral component of the epigenetic code in most higher eukaryotes. Exploring the extent to which DNA methylation can be altered under a specific condition and its heritability is important for elucidating the biological functions of this epigenetic modification. Here, we conducted MSAP analysis of rice plants with altered phenotypes subsequent to a low-dose Nd3+YAG laser irradiation. We found that all four methylation patterns at the 5′-CCGG sites that are analyzable by MSAP showed substantial changes in the immediately treated M0 plants. Interestingly, the frequencies of hypo- and hypermethylation were of similar extents, which largely offset each other and render the total methylation levels unchanged. Further analysis revealed that the altered methylation patterns were meiotically heritable to at least the M2 generation but accompanied with further changes in each generation. The methylation changes and their heritability of the metastable epigenetic state were verified by bisulfite sequencing of portion of the retrotranspon, Tos17, an established locus for assessing DNA methylation liability in rice. Real-time PCR assay indicated that the expression of various methylation-related chromatin genes was perturbed, and a Pearson correlation analysis showed that many of these genes, especially two AGOs (AGO4-1 and AGO4-2), were significantly correlated with the methylation pattern alterations. In addition, excisions of a MITE transposon, mPing, occurred rampantly in the laser irradiated plants and their progenies. Together, our results indicate that heritable DNA methylation changes can be readily induced by low-dose laser irradiation, and which can be accompanied by transpostional activation of transposable elements. PMID:28377781

  5. DNA methylation by CcrM activates the transcription of two genes required for the division of Caulobacter crescentus

    PubMed Central

    Gonzalez, Diego; Collier, Justine

    2013-01-01

    DNA methylation regulates many processes, including gene expression, by superimposing secondary information on DNA sequences. The conserved CcrM enzyme, which methylates adenines in GANTC sequences, is essential to the viability of several Alphaproteobacteria. In this study, we find that Caulobacter crescentus cells lacking the CcrM enzyme accumulate low levels of the two conserved FtsZ and MipZ proteins, leading to a severe defect in cell division. This defect can be compensated by the expression of the ftsZ gene from an inducible promoter or by spontaneous suppressor mutations that promote FtsZ accumulation. We show that CcrM promotes the transcription of the ftsZ and mipZ genes and that the ftsZ and mipZ promoter regions contain a conserved CGACTC motif that is critical to their activities and to their regulation by CcrM. In addition, our results suggest that the ftsZ promoter has the lowest activity when the CGACTC motif is non-methylated, an intermediate activity when it is hemi-methylated and the highest activity when it is fully methylated. The regulation of ftsZ expression by DNA methylation may explain why CcrM is essential in a subset of Alphaproteobacteria. PMID:23480529

  6. Study of solar activity and cosmic ray modulation during solar cycle 24 in comparison to previous solar cycle

    NASA Astrophysics Data System (ADS)

    Mishra, V. K.; Mishra, A. P.

    2016-12-01

    Based on the monthly data of sunspot numbers (SSN), sunspot area of full disc (SSA) and cosmic ray intensity (CRI) observed by neutron monitors (NM) located at Oulu (Cut off Rigidity = 0.8 GV) and Moscow (Cut off Rigidity = 2.3 GV), the trend of solar activity variation and cosmic ray modulation has been studied during the cycles 23 & 24. The SSN have maintained its minimum level exceptionally for a long period (July 2008-Aug. 2009) of time. The intensity of galactic cosmic rays measured by ground based detectors is the highest ever recorded by Oulu NM since April 1964 during the recent solar minimum. Furthermore, the maximum value of SSN is found to be very low in the present cycle in comparison to previous solar cycles (19-23). The correlation coefficient between SSN and CRI without and with time-lag as well as regression analysis during the solar cycle 24 (Jan. 2008-Dec. 2015) has been estimated and compared with previous solar cycle. Based on the maximum value of correlation coefficient, the time-lag during present solar cycle is found to be 4 and 10 months for both the stations, while it is 13-14 months during cycle 23. The behaviour of running cross correlation function has also been examined during present solar cycle and it is found that it attains its maximum value -0.8 to -0.9 for a long duration in comparison to previous cycles. The variation of SSN and SSA has also been compared and found that they are highly correlated to each other (r > .92) for both the cycles. In the light of exceptional behaviour of solar cycle 24, the trend of cosmic ray modulation has been discussed and compared with earlier cycles.

  7. [Suppression of cycling activity in sheep using parenteral progestagen treatment].

    PubMed

    Janett, F; Camponovo, L; Lanker, U; Hässig, M; Thun, R

    2004-03-01

    The objective of this study was to evaluate the effect of two synthetic progestagen preparations Chlormadinone acetate (CAP, Chronosyn, Veterinaria AG Zürich) and Medroxyprogesterone acetate (MPA, Nadigest, G Streuli & Co. Uznach) on cycling activity and fertility in sheep. A flock of 28 non pregnant white alpine sheep was randomly divided into three groups, A (n = 10), B (n = 9) and C (n = 9). During a period of 4 weeks the cycling activity was confirmed by blood progesterone analysis. Thereafter, the animals of group A were treated with 50 mg CAP, those of group B with 140 mg MPA and those of group C with physiological saline solution. All injections were given intramuscularly. Suppression of endogenous progesterone secretion lasted from 28 to 49 days (mean = 39 days) in group A and from 42 to 70 days (mean = 50 days) in group B. The synchronization effect of both preparations was unsatisfactory as the occurrence of first estrus was distributed over a period of 3 weeks in group A and 4 weeks in group B. These findings could also be confirmed by the lambing period which lasted 52 days in group A and 36 days in group B. Control animals lambed within 9 days due to the synchronizing effect of the ram. The first fertile estrus was observed 36 days (group A) and 45 days (group B) after the treatment. In group A all 10 animals and in groups B and C 8 of 9 ewes each became pregnant. Parenteral progestagen application with CAP and MPA is a simple, safe and reversible method of estrus suppression in the sheep. The minimal suppressive duration of 4 (CAP) and 5 weeks (MPA) is not sufficient when a period of 3 months (alpine pasture period) is desired.

  8. A New Simple Dynamo Model for Stellar Activity Cycle

    NASA Astrophysics Data System (ADS)

    Yokoi, N.; Schmitt, D.; Pipin, V.; Hamba, F.

    2016-06-01

    A new simple dynamo model for stellar activity cycle is proposed. By considering an inhomogeneous flow effect on turbulence, it is shown that turbulent cross helicity (velocity-magnetic-field correlation) enters the expression of turbulent electromotive force as the coupling coefficient for the mean absolute vorticity. This makes the present model different from the current α-Ω-type models in two main ways. First, in addition to the usual helicity (α) and turbulent magnetic diffusivity (β) effects, we consider the cross-helicity effect as a key ingredient of the dynamo process. Second, the spatiotemporal evolution of cross helicity is solved simultaneously with the mean magnetic fields. The basic scenario is as follows. In the presence of turbulent cross helicity, the toroidal field is induced by the toroidal rotation. Then, as in usual models, the α effect generates the poloidal field from the toroidal one. This induced poloidal field produces a turbulent cross helicity whose sign is opposite to the original one (negative production). With this cross helicity of the reversed sign, a reversal in field configuration starts. Eigenvalue analyses of the simplest possible model give a butterfly diagram, which confirms the above scenario and the equatorward migrations, the phase relationship between the cross helicity and magnetic fields. These results suggest that the oscillation of the turbulent cross helicity is a key for the activity cycle. The reversal of the cross helicity is not the result of the magnetic-field reversal, but the cause of the latter. This new model is expected to open up the possibility of the mean-field or turbulence closure dynamo approaches.

  9. DNMT3B isoforms without catalytic activity stimulate gene body methylation as accessory proteins in somatic cells.

    PubMed

    Duymich, Christopher E; Charlet, Jessica; Yang, Xiaojing; Jones, Peter A; Liang, Gangning

    2016-04-28

    Promoter DNA methylation is a key epigenetic mechanism for stable gene silencing, but is correlated with expression when located in gene bodies. Maintenance and de novo DNA methylation by catalytically active DNA methyltransferases (DNMT1 and DNMT3A/B) require accessory proteins such as UHRF1 and DNMT3L. DNMT3B isoforms are widely expressed, although some do not have active catalytic domains and their expression can be altered during cell development and tumourigenesis, questioning their biological roles. Here, we show that DNMT3B isoforms stimulate gene body methylation and re-methylation after methylation-inhibitor treatment. This occurs independently of the isoforms' catalytic activity, demonstrating a similar functional role to the accessory protein DNMT3L, which is only expressed in undifferentiated cells and recruits DNMT3A to initiate DNA methylation. This unexpected role for DNMT3B suggests that it might substitute for the absent accessory protein DNMT3L to recruit DNMT3A in somatic cells.

  10. Casticin inhibits the activity of transcription factor Sp1 and the methylation of RECK in MGC803 gastric cancer cells

    PubMed Central

    Yang, Fan; He, Kefei; Huang, Li; Zhang, Lingyan; Liu, Aixue; Zhang, Jiren

    2017-01-01

    The present study investigated the effect of casticin on reversion-inducing-cysteine-rich protein with kazal motifs (RECK) gene expression and intracellular methylation levels in MGC803 gastric cancer cells. Cells were treated with 1, 10 and 30 µmol/l casticin. Western blotting and reverse transcription-quantitative polymerase chain reaction assays were performed to determine the protein expression and mRNA levels of RECK and DNA methyltransferase 1 (DNMT1), respectively. High-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry was used to detect RECK methylation. In addition, MGC803 cell proliferation was measured by an MTT assay and the DNA-binding activity of transcription factor Sp1 was determined using an enzyme-linked immunosorbent assay. The results demonstrated that treatment with 1, 10 and 30 µmol/l casticin significantly increased RECK protein expression and mRNA levels. In addition, casticin (30 µmol/l) decreased RECK promoter methylation levels by 31%, global DNA methylation levels by 39% and nuclear methylation activity by 71.6%. Furthermore, casticin downregulated the mRNA levels and protein expression of DNMT1. The MTT assay demonstrated that MGC803 cell proliferation was inhibited by casticin treatment and DNA binding assays indicated that casticin reduced the DNA-binding activity of Sp1. The present study therefore indicated that casticin inhibits the proliferation of gastric cancer MGC803 cells by upregulating RECK gene expression and reducing intracellular methylation levels. PMID:28352361

  11. Chromatin and DNA methylation dynamics during retinoic acid-induced RET gene transcriptional activation in neuroblastoma cells

    PubMed Central

    Angrisano, T.; Sacchetti, S.; Natale, F.; Cerrato, A.; Pero, R.; Keller, S.; Peluso, S.; Perillo, B.; Avvedimento, V. E.; Fusco, A.; Bruni, C. B.; Lembo, F.; Santoro, M.; Chiariotti, L.

    2011-01-01

    Although it is well known that RET gene is strongly activated by retinoic acid (RA) in neuroblastoma cells, the mechanisms underlying such activation are still poorly understood. Here we show that a complex series of molecular events, that include modifications of both chromatin and DNA methylation state, accompany RA-mediated RET activation. Our results indicate that the primary epigenetic determinants of RA-induced RET activation differ between enhancer and promoter regions. At promoter region, the main mark of RET activation was the increase of H3K4me3 levels while no significant changes of the methylation state of H3K27 and H3K9 were observed. At RET enhancer region a bipartite chromatin domain was detected in unstimulated cells and a prompt demethylation of H3K27me3 marked RET gene activation upon RA exposure. Moreover, ChIP experiments demonstrated that EZH2 and MeCP2 repressor complexes were associated to the heavily methylated enhancer region in the absence of RA while both complexes were displaced during RA stimulation. Finally, our data show that a demethylation of a specific CpG site at the enhancer region could favor the displacement of MeCP2 from the heavily methylated RET enhancer region providing a novel potential mechanism for transcriptional regulation of methylated RA-regulated loci. PMID:20952403

  12. Base methylations in the double-stranded RNA by a fused methyltransferase bearing unwinding activity

    PubMed Central

    Kimura, Satoshi; Ikeuchi, Yoshiho; Kitahara, Kei; Sakaguchi, Yuriko; Suzuki, Takeo; Suzuki, Tsutomu

    2012-01-01

    Modifications of rRNAs are clustered in functional regions of the ribosome. In Helix 74 of Escherichia coli 23S rRNA, guanosines at positions 2069 and 2445 are modified to 7-methylguanosine(m7G) and N2-methylguanosine(m2G), respectively. We searched for the gene responsible for m7G2069 formation, and identified rlmL, which encodes the methyltransferase for m2G2445, as responsible for the biogenesis of m7G2069. In vitro methylation of rRNA revealed that rlmL encodes a fused methyltransferase responsible for forming both m7G2069 and m2G2445. We renamed the gene rlmKL. The N-terminal RlmL activity for m2G2445 formation was significantly enhanced by the C-terminal RlmK. Moreover, RlmKL had an unwinding activity of Helix 74, facilitating cooperative methylations of m7G2069 and m2G2445 during biogenesis of 50S subunit. In fact, we observed that RlmKL was involved in the efficient assembly of 50S subunit in a mutant strain lacking an RNA helicase deaD. PMID:22210896

  13. Involvement of autophagy in antitumor activity of folate-appended methyl-β-cyclodextrin.

    PubMed

    Onodera, Risako; Motoyama, Keiichi; Tanaka, Nao; Ohyama, Ayumu; Okamatsu, Ayaka; Higashi, Taishi; Kariya, Ryusho; Okada, Seiji; Arima, Hidetoshi

    2014-03-20

    Autophagy, the major lysosomal pathway for recycling intracellular components including organelles, is emerging as a key process regulating tumorigenesis and cancer therapy. Most recently, we newly synthesized folate-appended methyl-β-cyclodextrin (FA-M-β-CyD), and demonstrated the potential of FA-M-β-CyD as a new antitumor drug. In this study, we investigated whether anticancer activity of FA-M-β-CyD in folate receptor-α (FR-α)-positive tumor cells is involved in autophagy. In contrast to methyl-β-cyclodextrin (M-β-CyD), FA-M-β-CyD entered KB cells (FR-α (+)) through CLIC/GEEC endocytosis. No significant depression in the DNA content was observed in KB cells after treatment with FA-M-β-CyD. Additionally, the transmembrane potential of mitochondria after treatment with FA-M-β-CyD was drastically elevated. Meanwhile, FA-M-β-CyD induced the formation of autophagic vacuoles, which were partially colocalized with mitochondria, in KB cells. Taken together, these results suggest that FR-α-expressing cell-selective cytotoxic activity of FA-M-β-CyD could be mediated by the regulation of autophagy, rather than the induction of apoptosis.

  14. Exercise, physical activity, and exertion over the business cycle.

    PubMed

    Colman, Gregory; Dave, Dhaval

    2013-09-01

    Shifts in time and income constraints over economic expansions and contractions would be expected to affect individuals' behaviors. We explore the impact of the business cycle on individuals' exercise, time use, and total physical exertion, utilizing information on 112,000 individual records from the 2003-2010 American Time Use Surveys. In doing so, we test a key causal link that has been hypothesized in the relation between unemployment and health, but not heretofore assessed. Using more precise measures of exercise (and other activities) than previous studies, we find that as work-time decreases during a recession, recreational exercise, TV-watching, sleeping, childcare, and housework increase. This, however, does not compensate for the decrease in work-related exertion due to job-loss, and total physical exertion declines. These effects are strongest among low-educated men, which is validating given that employment in the Great Recession has declined most within manufacturing, mining, and construction. We also find evidence of intra-household spillover effects, wherein individuals respond to shifts in spousal employment conditional on their own labor supply. The decrease in total physical activity during recessions is especially problematic for vulnerable populations concentrated in boom-and-bust industries, and may have longer-term effects on obesity and related health outcomes.

  15. Methionine sulfoxide reductase regulates brain catechol-O-methyl transferase activity

    PubMed Central

    Moskovitz, Jackob; Walss-Bass, Consuelo; Cruz, Dianne A; Thompson, Peter M.; Bortolato, Marco

    2015-01-01

    Catechol-O-methyl transferase (COMT) plays a key role in the degradation of brain dopamine (DA). Specifically, low COMT activity results in higher DA levels in the prefrontal cortex (PFC), thereby reducing the vulnerability for attentional and cognitive deficits in both psychotic and healthy individuals. COMT activity is markedly reduced by a non-synonymous SNP that generates a valine-to-methionine substitution on the residue 108/158, by means of as-yet incompletely understood posttranslational mechanisms. One posttranslational modification is methionine sulfoxide, which can be reduced by the methionine sulfoxide reductase (Msr) A and B enzymes. We used recombinant COMT proteins (Val/Met108) and mice (wild-type (WT) and MsrA knockout) to determine the effect of methionine oxidation on COMT activity and COMT interaction with Msr, through a combination of enzymatic activity and Western blot assays. Recombinant COMT activity is positively regulated by MsrA, especially under oxidative conditions, while brains of MsrA knockout mice exhibited lower COMT activity (as compared with their WT counterparts). These results suggest that COMT activity may be reduced by methionine oxidation, and point to Msr as a key molecular determinant for the modulation of COMT activity in the brain. The role of Msr in modulating cognitive functions in healthy individuals and schizophrenia patients is yet to be determined. PMID:24735585

  16. Methylated Cytokinins from the Phytopathogen Rhodococcus fascians Mimic Plant Hormone Activity.

    PubMed

    Radhika, Venkatesan; Ueda, Nanae; Tsuboi, Yuuri; Kojima, Mikiko; Kikuchi, Jun; Kudo, Takuji; Sakakibara, Hitoshi

    2015-10-01

    Cytokinins (CKs), a class of phytohormones that regulate plant growth and development, are also synthesized by some phytopathogens to disrupt the hormonal balance and to facilitate niche establishment in their hosts. Rhodococcus fascians harbors the fasciation (fas) locus, an operon encoding several genes homologous to CK biosynthesis and metabolism. This pathogen causes unique leafy gall symptoms reminiscent of CK overproduction; however, bacterial CKs have not been clearly correlated with the severe symptoms, and no virulence-associated unique CKs or analogs have been identified. Here, we report the identification of monomethylated N(6)-(∆(2)-isopentenyl)adenine and dimethylated N(6)-(∆(2)-isopentenyl)adenine (collectively, methylated cytokinins [MeCKs]) from R. fascians. MeCKs were recognized by a CK receptor and up-regulated type-A ARABIDOPSIS THALIANA RESPONSE REGULATOR genes. Treatment with MeCKs inhibited root growth, a hallmark of CK action, whereas the receptor mutant was insensitive. MeCKs were retained longer in planta than canonical CKs and were poor substrates for a CK oxidase/dehydrogenase, suggesting enhanced biological stability. MeCKs were synthesized by S-adenosyl methionine-dependent methyltransferases (MT1 and MT2) that are present upstream of the fas genes. The best substrate for methylation was isopentenyl diphosphate. MT1 and MT2 catalyzed distinct methylation reactions; only the MT2 product was used by FAS4 to synthesize monomethylated N(6)-(∆(2)-isopentenyl)adenine. The MT1 product was dimethylated by MT2 and used as a substrate by FAS4 to produce dimethylated N(6)-(∆(2)-isopentenyl)adenine. Chemically synthesized MeCKs were comparable in activity. Our results strongly suggest that MeCKs function as CK mimics and play a role in this plant-pathogen interaction.

  17. Methylated Cytokinins from the Phytopathogen Rhodococcus fascians Mimic Plant Hormone Activity1[OPEN

    PubMed Central

    Radhika, Venkatesan; Ueda, Nanae; Tsuboi, Yuuri; Kojima, Mikiko; Kikuchi, Jun; Kudo, Takuji; Sakakibara, Hitoshi

    2015-01-01

    Cytokinins (CKs), a class of phytohormones that regulate plant growth and development, are also synthesized by some phytopathogens to disrupt the hormonal balance and to facilitate niche establishment in their hosts. Rhodococcus fascians harbors the fasciation (fas) locus, an operon encoding several genes homologous to CK biosynthesis and metabolism. This pathogen causes unique leafy gall symptoms reminiscent of CK overproduction; however, bacterial CKs have not been clearly correlated with the severe symptoms, and no virulence-associated unique CKs or analogs have been identified. Here, we report the identification of monomethylated N6-(∆2-isopentenyl)adenine and dimethylated N6-(∆2-isopentenyl)adenine (collectively, methylated cytokinins [MeCKs]) from R. fascians. MeCKs were recognized by a CK receptor and up-regulated type-A ARABIDOPSIS THALIANA RESPONSE REGULATOR genes. Treatment with MeCKs inhibited root growth, a hallmark of CK action, whereas the receptor mutant was insensitive. MeCKs were retained longer in planta than canonical CKs and were poor substrates for a CK oxidase/dehydrogenase, suggesting enhanced biological stability. MeCKs were synthesized by S-adenosyl methionine-dependent methyltransferases (MT1 and MT2) that are present upstream of the fas genes. The best substrate for methylation was isopentenyl diphosphate. MT1 and MT2 catalyzed distinct methylation reactions; only the MT2 product was used by FAS4 to synthesize monomethylated N6-(∆2-isopentenyl)adenine. The MT1 product was dimethylated by MT2 and used as a substrate by FAS4 to produce dimethylated N6-(∆2-isopentenyl)adenine. Chemically synthesized MeCKs were comparable in activity. Our results strongly suggest that MeCKs function as CK mimics and play a role in this plant-pathogen interaction. PMID:26251309

  18. T Cell Receptor-induced Activation and Apoptosis In Cycling Human T Cells Occur throughout the Cell Cycle

    PubMed Central

    Karas, Michael; Zaks, Tal Z.; JL, Liu; LeRoith, Derek

    1999-01-01

    Previous studies have found conflicting associations between susceptibility to activation-induced cell death and the cell cycle in T cells. However, most of the studies used potentially toxic pharmacological agents for cell cycle synchronization. A panel of human melanoma tumor-reactive T cell lines, a CD8+ HER-2/neu-reactive T cell clone, and the leukemic T cell line Jurkat were separated by centrifugal elutriation. Fractions enriched for the G0–G1, S, and G2–M phases of the cell cycle were assayed for T cell receptor-mediated activation as measured by intracellular Ca2+ flux, cytolytic recognition of tumor targets, and induction of Fas ligand mRNA. Susceptibility to apoptosis induced by recombinant Fas ligand and activation-induced cell death were also studied. None of the parameters studied was specific to a certain phase of the cell cycle, leading us to conclude that in nontransformed human T cells, both activation and apoptosis through T cell receptor activation can occur in all phases of the cell cycle. PMID:10588669

  19. Synthesis, characterization, and antimicrobial activity of poly(acrylonitrile-co-methyl methacrylate) with silver nanoparticles.

    PubMed

    El-Aassar, M R; Hafez, Elsayed E; Fouda, Moustafa M G; Al-Deyab, Salem S

    2013-10-01

    Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field.

  20. 13C-Methyl isocyanide as an NMR probe for cytochrome P450 active sites

    PubMed Central

    McCullough, Christopher R.; Pullela, Phani Kumar; Im, Sang-Choul; Waskell, Lucy

    2012-01-01

    The cytochromes P450 (CYPs) play a central role in many biologically important oxidation reactions, including the metabolism of drugs and other xenobiotic compounds. Because they are often assayed as both drug targets and anti-targets, any tools that provide: (a) confirmation of active site binding and (b) structural data, would be of great utility, especially if data could be obtained in reasonably high throughput. To this end, we have developed an analog of the promiscuous heme ligand, cyanide, with a 13CH3-reporter attached. This 13C-methyl isocyanide ligand binds to bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. It can be used in a rapid 1D experiment to identify binders, and provides a qualitative measure of structural changes in the active site. PMID:19199046

  1. Serum pyrrolidone carboxypeptidase activity in N-methyl-nitrosourea induced rat breast cancer.

    PubMed

    Carrera, M P; Ramírez-Expósito, M J; Valenzuela, M T; García, M J; Mayas, M D; Martínez-Martos, J M

    2003-08-01

    Pyrrolidone carboxypeptidase (Pcp) (E.C. 3.4.19.3) is an omega peptidase widely distributed in animal fluids and tissues and hydrolyses N-terminal pyroglutamic residues from biologically active peptides such as gonadotropin releasing hormone (GnRH). Previous results obtained by us showed a decrease in human breast cancer Pcp activity, suggesting that this enzyme activity or its putative substrates may play a major role in breast cancer pathogenesis. The aim of the present work is to analyse serum Pcp activity in N-methyl-nitrosourea (NMU) induced rat mammary tumours using pyroglutamyl-beta-naphthylamide as substrate. Serum Pcp activity was significantly lower in NMU-treated rats than in controls. Moreover, multiple regression analysis showed a significant correlation between Pcp activity and the number and size of tumours and the body weight of the animals. Since NMU-induced carcinomas are mainly oestrogen-dependent, the decrease observed in Pcp activity may reflect an increase in circulating levels of GnRH that lead to an increase in gonadal steroid hormones production responsible, at least in part, for the initiation and promotion of the disease.

  2. Long-Range Solar Activity Predictions: A Reprieve from Cycle #24's Activity

    NASA Technical Reports Server (NTRS)

    Richon, K.; Schatten, K.

    2003-01-01

    We discuss the field of long-range solar activity predictions and provide an outlook into future solar activity. Orbital predictions for satellites in Low Earth Orbit (LEO) depend strongly on exospheric densities. Solar activity forecasting is important in this regard, as the solar ultra-violet (UV) and extreme ultraviolet (EUV) radiations inflate the upper atmospheric layers of the Earth, forming the exosphere in which satellites orbit. Rather than concentrate on statistical, or numerical methods, we utilize a class of techniques (precursor methods) which is founded in physical theory. The geomagnetic precursor method was originally developed by the Russian geophysicist, Ohl, using geomagnetic observations to predict future solar activity. It was later extended to solar observations, and placed within the context of physical theory, namely the workings of the Sun s Babcock dynamo. We later expanded the prediction methods with a SOlar Dynamo Amplitude (SODA) index. The SODA index is a measure of the buried solar magnetic flux, using toroidal and poloidal field components. It allows one to predict future solar activity during any phase of the solar cycle, whereas previously, one was restricted to making predictions only at solar minimum. We are encouraged that solar cycle #23's behavior fell closely along our predicted curve, peaking near 192, comparable to the Schatten, Myers and Sofia (1996) forecast of 182+/-30. Cycle #23 extends from 1996 through approximately 2006 or 2007, with cycle #24 starting thereafter. We discuss the current forecast of solar cycle #24, (2006-2016), with a predicted smoothed F10.7 radio flux of 142+/-28 (1-sigma errors). This, we believe, represents a reprieve, in terms of reduced fuel costs, etc., for new satellites to be launched or old satellites (requiring reboosting) which have been placed in LEO. By monitoring the Sun s most deeply rooted magnetic fields; long-range solar activity can be predicted. Although a degree of uncertainty

  3. The Human ARF Cell Cycle Regulatory Gene Promoter Is a CpG Island Which Can Be Silenced by DNA Methylation and Down-Regulated by Wild-Type p53

    PubMed Central

    Robertson, Keith D.; Jones, Peter A.

    1998-01-01

    The INK4a/ARF locus encodes two proteins involved in tumor suppression in a manner virtually unique in mammalian cells. Distinct first exons, driven from separate promoters, splice onto a common exon 2 and 3 but utilize different reading frames to produce two completely distinct proteins, both of which play roles in cell cycle control. INK4a, a critical element of the retinoblastoma gene pathway, binds to and inhibits the activities of CDK4 and CDK6, while ARF, a critical element of the p53 pathway, increases the level of functional p53 via interaction with MDM2. Here we clone and characterize the promoter of the human ARF gene and show that it is a CpG island characteristic of a housekeeping gene which contains numerous Sp1 sites. Both ARF and INK4a are coordinately expressed in cells except when their promoter regions become de novo methylated. In one of these situations, ARF transcription could be reactivated by treatment with the DNA methylation inhibitor 5-aza-2′-deoxycytidine, and the reactivation kinetics of ARF and INK4a were found to differ slightly in a cell line in which both genes were silenced by methylation. The ARF promoter was also found to be highly responsive to E2F1 expression, in keeping with previous results at the RNA level. Lastly, transcription from the ARF promoter was down-regulated by wild-type p53 expression, and the magnitude of the effect correlated with the status of the endogenous p53 gene. This finding points to the existence of an autoregulatory feedback loop between p53, MDM2, and ARF, aimed at keeping p53 levels in check. PMID:9774662

  4. Spontaneous sleep-wake cycle and sleep deprivation differently induce Bdnf1, Bdnf4 and Bdnf9a DNA methylation and transcripts levels in the basal forebrain and frontal cortex in rats.

    PubMed

    Ventskovska, Olena; Porkka-Heiskanen, Tarja; Karpova, Nina N

    2015-04-01

    Brain-derived neurotrophic factor (Bdnf) regulates neuronal plasticity, slow wave activity and sleep homeostasis. Environmental stimuli control Bdnf expression through epigenetic mechanisms, but there are no data on epigenetic regulation of Bdnf by sleep or sleep deprivation. Here we investigated whether 5-methylcytosine (5mC) DNA modification at Bdnf promoters p1, p4 and p9 influences Bdnf1, Bdnf4 and Bdnf9a expression during the normal inactive phase or after sleep deprivation (SD) (3, 6 and 12 h, end-times being ZT3, ZT6 and ZT12) in rats in two brain areas involved in sleep regulation, the basal forebrain and cortex. We found a daytime variation in cortical Bdnf expression: Bdnf1 expression was highest at ZT6 and Bdnf4 lowest at ZT12. Such variation was not observed in the basal forebrain. Also Bdnf p1 and p9 methylation levels differed only in the cortex, while Bdnf p4 methylation did not vary in either area. Factorial analysis revealed that sleep deprivation significantly induced Bdnf1 and Bdnf4 with the similar pattern for Bdnf9a in both basal forebrain and cortex; 12 h of sleep deprivation decreased 5mC levels at the cortical Bdnf p4 and p9. Regression analysis between the 5mC promoter levels and the corresponding Bdnf transcript expression revealed significant negative correlations for the basal forebrain Bdnf1 and cortical Bdnf9a transcripts in only non-deprived rats, while these correlations were lost after sleep deprivation. Our results suggest that Bdnf transcription during the light phase of undisturbed sleep-wake cycle but not after SD is regulated at least partially by brain site-specific DNA methylation.

  5. A Krebs Cycle Component Limits Caspase Activation Rate through Mitochondrial Surface Restriction of CRL Activation.

    PubMed

    Aram, Lior; Braun, Tslil; Braverman, Carmel; Kaplan, Yosef; Ravid, Liat; Levin-Zaidman, Smadar; Arama, Eli

    2016-04-04

    How cells avoid excessive caspase activity and unwanted cell death during apoptotic caspase-mediated removal of large cellular structures is poorly understood. We investigate caspase-mediated extrusion of spermatid cytoplasmic contents in Drosophila during spermatid individualization. We show that a Krebs cycle component, the ATP-specific form of the succinyl-CoA synthetase β subunit (A-Sβ), binds to and activates the Cullin-3-based ubiquitin ligase (CRL3) complex required for caspase activation in spermatids. In vitro and in vivo evidence suggests that this interaction occurs on the mitochondrial surface, thereby limiting the source of CRL3 complex activation to the vicinity of this organelle and reducing the potential rate of caspase activation by at least 60%. Domain swapping between A-Sβ and the GTP-specific SCSβ (G-Sβ), which functions redundantly in the Krebs cycle, show that the metabolic and structural roles of A-Sβ in spermatids can be uncoupled, highlighting a moonlighting function of this Krebs cycle component in CRL activation.

  6. Methyl Jasmonate Enhances Antioxidant Activity, Flavonoid Content and Antiproliferation of Human Cancer Cells in Blackberries (Rubus spp.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of preharvest methyl jasmonate (MJ) application on fruit quality, antioxidant activity and flavonoid content in blackberries (Rubus spp.) were determined. Anticancer activity against human lung A549 cells and HL-60 leukemia cells was also evaluated. Three blackberry cultivars (Chester T...

  7. Rotating single cycle two-phase thermally activated heat pump

    SciTech Connect

    Fabris, G.

    1993-06-08

    A thermally activated heat pump is described which utilizes single working fluid which as a whole passes consecutively through all parts of the apparatus in a closed loop series; the working fluid in low temperature saturated liquid state at condensation is pumped to higher pressure with a pump; subsequently heat is added to the liquid of increased pressure, the liquid via the heating is brought to a high temperature saturated liquid state; the high temperature liquid passes and flashes subsequently in form of two-phase flow through a rotating two-phase flow turbine; in such a way the working fluid performs work on the two-phase turbine which in turn powers the liquid pump and a lower compressor; two-phase flow exiting the two-phase turbine separated by impinging tangentially on housing of the turbine; low temperature heat is added to the housing in such a way evaporating the separated liquid on the housing; in such a way the liquid is fully vaporized the vapor then enters a compressor, the compressor compresses the vapor to a higher condensation pressure and corresponding increased temperature, the vapor at the condensation pressure enters a condenser whereby heat is rejected and the vapor is fully condensed into state of saturated liquid, mid saturated liquid enters the pump and repeats the cycle.

  8. Quantifying promoter activity during the developmental cycle of Chlamydia trachomatis

    PubMed Central

    Cong, Yanguang; Gao, Leiqiong; Zhang, Yan; Xian, Yuqi; Hua, Ziyu; Elaasar, Hiba; Shen, Li

    2016-01-01

    Chlamydia trachomatis is an important human pathogen that undergoes a characteristic development cycle correlating with stage-specific gene expression profiles. Taking advantage of recent developments in the genetic transformation in C. trachomatis, we constructed a versatile green fluorescent protein (GFP) reporter system to study the development-dependent function of C. trachomatis promoters in an attempt to elucidate the mechanism that controls C. trachomatis adaptability. We validated the use of the GFP reporter system by visualizing the activity of an early euo gene promoter. Additionally, we uncovered a new ompA promoter, which we named P3, utilizing the GFP reporter system combined with 5′ rapid amplification of cDNA ends (RACE), in vitro transcription assays, real-time quantitative RT-PCR (RT-qPCR), and flow cytometry. Mutagenesis of the P3 region verifies that P3 is a new class of C. trachomatis σ66-dependent promoter, which requires an extended −10 TGn motif for transcription. These results corroborate complex developmentally controlled ompA expression in C. trachomatis. The exploitation of genetically labeled C. trachomatis organisms with P3-driven GFP allows for the observation of changes in ompA expression in response to developmental signals. The results of this study could be used to complement previous findings and to advance understanding of C. trachomatis genetic expression. PMID:27263495

  9. An active thermal compensator for closed-cycle helium refrigerators

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.; Hillman, J. J.

    1977-01-01

    A technique was developed for reducing the amplitude of the temperature oscillation in He closed-cyle refrigerators. The device uses a semiconductor diode as a heating element to actively supply a small oscillating input of heat at a point between the laser and the cold-tip to cancel the heat oscillations due to the refrigerator. It was found that the heater diode could drive the temperature of the heat sink more effectively, i.e., with lower current and therefore less heat, if the heat sink was insulated slightly from the rest of the mount. A sine-wave generator was used to drive the programmable supply which provided the offset current to the heater diode. By matching the frequency and phase of the oscillator to that of the refrigerator cycle, and by adjusting the amplitude of the oscillator signal, the temperature fluctuations at the laser could be minimized. Residual fluctuations were about 0.003K peak-to-peak, at an operating temperature of 9.5K.

  10. A Summary of Closed Brayton Cycle Development Activities at NASA

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2009-01-01

    NASA has been involved in the development of Closed Brayton Cycle (CBC) power conversion technology since the 1960's. CBC systems can be coupled to reactor, isotope, or solar heat sources and offer the potential for high efficiency, long life, and scalability to high power. In the 1960's and 1970's, NASA and industry developed the 10 kW Brayton Rotating Unit (BRU) and the 2 kW mini-BRU demonstrating technical feasibility and performance, In the 1980's, a 25 kW CBC Solar Dynamic (SD) power system option was developed for Space Station Freedom and the technology was demonstrated in the 1990's as part of the 2 kW SO Ground Test Demonstration (GTD). Since the early 2000's, NASA has been pursuing CBC technology for space reactor applications. Before it was cancelled, the Jupiter Icy Moons Orbiter (HMO) mission was considering a 100 kWclass CBC system coupled to a gas-cooled fission reactor. Currently, CBC technology is being explored for Fission Surface Power (FSP) systems to provide base power on the moon and Mars. These recent activities have resulted in several CBC-related technology development projects including a 50 kW Alternator Test Unit, a 20 kW Dual Brayton Test Loop, a 2 kW Direct Drive Gas Brayton Test Loop, and a 12 kW FSP Power Conversion Unit design.

  11. Semi-annual Sq-variation in solar activity cycle

    NASA Astrophysics Data System (ADS)

    Pogrebnoy, V.; Malosiev, T.

    The peculiarities of semi-annual variation in solar activity cycle have been studied. The data from observatories having long observational series and located in different latitude zones were used. The following observatories were selected: Huancayo (magnetic equator), from 1922 to 1959; Apia (low latitudes), from 1912 to 1961; Moscow (middle latitudes), from 1947 to 1965. Based on the hourly values of H-components, the average monthly diurnal amplitudes (a difference between midday and midnight values), according to five international quiet days, were computed. Obtained results were compared with R (relative sunspot numbers) in the ranges of 0-30R, 40-100R, and 140-190R. It was shown, that the amplitude of semi-annual variation increases with R, from minimum to maximum values, on average by 45%. At equatorial Huancayo observatory, the semi-annual Sq(H)-variation appears especially clearly: its maximums take place at periods of equinoxes (March-April, September-October), and minimums -- at periods of solstices (June-July, December-January). At low (Apia observatory) and middle (Moscow observatory) latitudes, the character of semi-annual variation is somewhat different: it appears during the periods of equinoxes, but considerably less than at equator. Besides, with the growth of R, semi-annual variation appears against a background of annual variation, in the form of second peaks (maximum in June). At observatories located in low and middle latitudes, second peaks become more appreciable with an increase of R (March-April and September-October). During the periods of low solar activity, they are insignificant. This work has been carried out with the support from International Scientific and Technology Center (Project #KR-214).

  12. The effects of active chlorine on photooxidation of 2-methyl-2-butene.

    PubMed

    Im, Yunseok; Jang, Myoseon; Delcomyn, Carrie A; Henley, Michael V; Hearn, John D

    2011-06-01

    Active chlorine comprising hypochlorite (OCl⁻), hypochlorous acid (HOCl) and chlorine (Cl₂) is the active constituent in bleach formulations for a variety of industrial and consumer applications. However, the strong oxidative reactivity of active chlorine can cause adverse effects on both human health and the environment. In this study, aerosolized Oxone® [2KHSO₅, KHSO₄, K₂SO₄] with saline solution has been utilized to produce active chlorine (HOCl and Cl₂). To investigate the impact of active chlorine on volatile organic compound (VOC) oxidation, 2-methyl-2-butene (MB) was photoirradiated in the presence of active chlorine using a 2-m³ Teflon film indoor chamber. The resulting carbonyl products produced from photooxidation of MB were derivatized with O-(2,3,4,5,6-pentafluorobenzyl) hydroxyamine hydrochloride (PFBHA) and analyzed using gas chromatograph-ion trap mass spectrometer (GC/ITMS). The photooxidation of MB in the presence of active chlorine was simulated with an explicit kinetic model using a chemical solver (Morpho) which included both Master Chemical Mechanism (MCM) and Cl radical reactions. The reaction rate constants of a Cl radical with MB and its oxidized products were estimated using a Structure-Reactivity Relationship method. Under dark conditions no effect of active chlorine on MB oxidation was apparent, whereas under simulated daylight conditions (UV irradiation) rapid MB oxidation was observed due to photo-dissociation of active chlorine. The model simulation agrees with chamber data showing rapid production of oxygenated products that are characterized using GC/ITMS. Ozone formation was enhanced when MB was oxidized in the presence of irradiated active chlorine and NO(x).

  13. Mercury methylation in periphyton of the Florida Everglades

    USGS Publications Warehouse

    Cleckner, L.B.; Gilmour, C.C.; Hurley, J.P.; Krabbenhoft, D.P.

    1999-01-01

    Trophic accumulation of mercury (Hg) in aquatic ecosystems is of global concern due to health effects associated with eating fish with elevated Hg levels. The methylated form of Hg bioaccumulates so it is important to understand how inorganic Hg is transformed to methylmercury in the environment. Here, a new site for Hg methylation, the periphyton communities that are prevalent in the Florida Everglades, is described. It is hypothesized that periphyton communities that support an active microbial sulfur cycle support Hg methylation. This new methylation site has implications for trophic transfer of methylmercury since periphyton can be the base of the food web in aquatic ecosystems.

  14. Active longitudes in the period of overlap of 11-year cycles

    NASA Astrophysics Data System (ADS)

    Kramynin, A. P.; Mikhalina, F. A.

    2016-12-01

    It is shown that "active longitudes" for the sunspots of old and new cycles manifest themselves approximately in the same longitudinal intervals and remain for several 11-year cycles. To be more accurate, they vanish in some cycles but then appear again at the same longitudinal intervals in the other cycles. The entire period is characterized by a total of four active longitudes. The old-cycle sunspots observed at low equatorial latitudes in the Northern and Southern Hemispheres are characterized by a shift by ≈180°, which indicates antipodality of the active longitudes in the Northern and Southern Hemispheres. In the case of highlatitude sunspots (new-cycle sunspots), the best correlation is observed for the shift of ≈90°. There is supposedly a dependence of the rotation speed of active longitudes on the secular cycle.

  15. Distribution of the activity of the Sun during an average solar cycle

    NASA Astrophysics Data System (ADS)

    Svoreň, J.

    2015-12-01

    The paper offers a look at distribution of solar activity during an average solar cycle. Activity profiles in solar cycles from 13 to 17 and from 18 to 22 were studied based on the relative sunspot numbers. The average values for both groups of cycles were derived after the standardization to the maximum monthly value. Obtained values differed minimally, allowing us to derive a uniform distribution of activity for the entire review period from 1890 to 1996. The derived model of the distribution of activity in an average solar cycle allows us to predict the maximum value of an activity cycle with an advance of approximately 5 years based only on the value obtained in the first year of the cycle. This can be of use for, e.g., the planning of long-term human activities in outer space.

  16. Altered regulation of DNA ligase IV activity by aberrant promoter DNA methylation and gene amplification in colorectal cancer.

    PubMed

    Kuhmann, Christine; Li, Carmen; Kloor, Matthias; Salou, Mariam; Weigel, Christoph; Schmidt, Christopher R; Ng, Linda W C; Tsui, Wendy W Y; Leung, Suet Y; Yuen, Siu T; Becker, Natalia; Weichenhan, Dieter; Plass, Christoph; Schmezer, Peter; Chan, Tsun L; Popanda, Odilia

    2014-04-15

    Colorectal cancer (CRC) presents as a very heterogeneous disease which cannot sufficiently be characterized with the currently known genetic and epigenetic markers. To identify new markers for CRC we scrutinized the methylation status of 231 DNA repair-related genes by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression of these genes could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A and LIG4 in CRC which was confirmed in two CRC patient groups with different ethnicity. DNA ligase IV (LIG4) showed strong differential promoter methylation (up to 60%) which coincided with downregulation of mRNA in 51% of cases. This functional association of LIG4 methylation and gene expression was supported by LIG4 re-expression in 5-aza-2'-deoxycytidine-treated colon cancer cell lines, and reduced ligase IV amounts and end-joining activity in extracts of tumors with hypermethylation. Methylation of LIG4 was not associated with other genetic and epigenetic markers of CRC in our study. As LIG4 is located on chromosome 13 which is frequently amplified in CRC, two loci were tested for gene amplification in a subset of 47 cases. Comparison of amplification, methylation and expression data revealed that, in 30% of samples, the LIG4 gene was amplified and methylated, but expression was not changed. In conclusion, hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for CRC independent of known markers.

  17. Ammonium sulfide-assisted hydrothermal activation of palygorskite for enhanced adsorption of methyl violet.

    PubMed

    Tian, Guangyan; Wang, Wenbo; Kang, Yuru; Wang, Aiqin

    2016-03-01

    Herein, palygorskite (PAL) was activated via a simple hydrothermal process in the presence of ammonium sulfide, and the effects of activation on the microstructure, physico-chemical feature and adsorption behaviors of PAL were intensively investigated. The hydrothermal process evidently improved the dispersion of PAL crystal bundles, increased surface negative charges and built more active -Si-O(-) groups served as the new "adsorption sites". The adsorption property of the activated PAL for Methyl Violet (MV) was systematically investigated by optimizing the adsorption variables, including pH, ionic strength, contact time and initial MV concentration. The activated PAL exhibited a superior adsorption capability to the raw PAL for the removal of MV (from 156.05 to 218.11mg/g). The kinetics for MV adsorption followed pseudo second-order kinetic models, while the isotherm and thermodynamics results showed that the adsorption pattern well followed the Langmuir model. The structure analysis of PAL before and after adsorption demonstrated that electrostatic interaction and chemical association of -X-O(-) are the prominent driving forces for the adsorption process.

  18. Screening for catalytically active Type II restriction endonucleases using segregation-induced methylation deficiency

    PubMed Central

    Ukanis, Mindaugas; Sapranauskas, Rimantas; Lubys, Arvydas

    2012-01-01

    Type II restriction endonucleases (REases) are one of the basic tools of recombinant DNA technology. They also serve as models for elucidation of mechanisms for both site-specific DNA recognition and cleavage by proteins. However, isolation of catalytically active mutants from their libraries is challenging due to the toxicity of REases in the absence of protecting methylation, and techniques explored so far had limited success. Here, we present an improved SOS induction-based approach for in vivo screening of active REases, which we used to isolate a set of active variants of the catalytic mutant, Cfr10IE204Q. Detailed characterization of plasmids from 64 colonies screened from the library of ∼200 000 transformants revealed 29 variants of cfr10IR gene at the level of nucleotide sequence and 15 variants at the level of amino acid sequence, all of which were able to induce SOS response. Specific activity measurements of affinity-purified mutants revealed >200-fold variance among them, ranging from 100% (wild-type isolates) to 0.5% (S188C mutant), suggesting that the technique is equally suited for screening of mutants possessing high or low activity and confirming that it may be applied for identification of residues playing a role in catalysis. PMID:22753027

  19. O-Methylated flavonol isorhamnetin prevents acute inflammation through blocking of NF-κB activation.

    PubMed

    Yang, Ji Hye; Kim, Sang Chan; Shin, Bo Yeon; Jin, So Hee; Jo, Mi Jeong; Jegal, Kyung Hwan; Kim, Young Woo; Lee, Jong Rok; Ku, Sae Kwang; Cho, Il Je; Ki, Sung Hwan

    2013-09-01

    Here, we isolated isorhamnetin, a natural 3'-O-methylated flavonoid, from water dropwort (Oenanthe javanica, Umbelliferae) and investigated its ability to protect against acute inflammation in vivo and in vitro. To induce paw swelling, the hind paw of each rat was injected with a carrageenan 1h after vehicle or isorhamnetin treatment. In vitro effect and mechanism studies were performed in lipopolysaccharide (LPS)-activated macrophages. Administration of isorhamnetin markedly inhibited the swelling volume and the thickness of hind paws. Moreover, isorhamnetin significantly reduced inflammatory cell infiltration and pro-inflammatory gene expression in rats. Isorhamnetin pretreatment inhibited inducible nitric oxide synthase (iNOS) expression and NO release in LPS-stimulated cells. Activation of nuclear factor-kappa B (NF-κB) and activating protein-1 (AP-1) is the key step in the iNOS gene induction. Isorhamnetin specifically inhibited NF-κB luciferase activity, but not AP-1. Pretreatment with isorhamnetin suppressed NF-κB nuclear translocation in accordance with decreased phosphorylation and degradation of inhibitory-κB. Consistently, TNF-α, IL-1β and IL-6 expression, representative NF-κB target genes, were almost completely prohibited by isorhamnetin. Furthermore, isorhamnetin inhibited LPS-induced JNK and AKT/IKKα/β phosphorylation. Our results suggest that isorhamnetin inhibited JNK, and AKT/IKKα/β activation, leading to NF-κB inactivation, which might contribute to the inhibition of the acute inflammatory response.

  20. Structure-activity relationship of daptomycin analogues with substitution at (2S, 3R) 3-methyl glutamic acid position.

    PubMed

    Lin, Du'an; Lam, Hiu Yung; Han, Wenbo; Cotroneo, Nicole; Pandya, Bhaumik A; Li, Xuechen

    2017-02-01

    Daptomycin is a highly effective lipopeptide antibiotic against Gram-positive pathogens. The presence of (2S, 3R) 3-methyl glutamic acid (mGlu) in daptomycin has been found to be important to the antibacterial activity. However the role of (2S, 3R) mGlu is yet to be revealed. Herein, we reported the syntheses of three daptomycin analogues with (2S, 3R) mGlu substituted by (2S, 3R) methyl glutamine (mGln), dimethyl glutamic acid and (2S, 3R) ethyl glutamic acid (eGlu), respectively, and their antibacterial activities. The detailed synthesis of dimethyl glutamic acid was also reported.

  1. Set7 mediated Gli3 methylation plays a positive role in the activation of Sonic Hedgehog pathway in mammals

    PubMed Central

    Fu, Lin; Wu, Hailong; Cheng, Steven Y; Gao, Daming; Zhang, Lei; Zhao, Yun

    2016-01-01

    Hedgehog signaling plays very important roles in development and cancers. Vertebrates have three transcriptional factors, Gli1, Gli2 and Gli3. Among them, Gli3 is a very special transcriptional factor which closely resembles Cubitus interruptus (Ci, in Drosophila) structurally and functionally as a ‘double agent’ for Shh target gene expression. Here we show that Gli3 full-length, but not the truncated form, can be methylated at K436 and K595. This methylation is specifically catalyzed by Set7, a lysine methyltransferase (KMT). Methylation at K436 and K595 respectively increases the stability and DNA binding ability of Gli3, resulting in an enhancement of Shh signaling activation. Furthermore, functional experiments indicate that the Gli3 methylation contributes to the tumor growth and metastasis in non-small cell lung cancer in vitro and in vivo. Therefore, we propose that Set7 mediated methylation is a novel PTM of Gli3, which positively regulates the transactivity of Gli3 and the activation of Shh signaling. DOI: http://dx.doi.org/10.7554/eLife.15690.001 PMID:27146893

  2. Extracellular enzyme activity and biogeochemical cycling in restored prairies

    NASA Astrophysics Data System (ADS)

    Lynch, L.; Hernandez, D.; Schade, J. D.

    2011-12-01

    Winter microbial activity in mid-latitude prairie ecosystems is thermally sensitive and significantly influenced by snow depth. Snow insulates the soil column facilitating microbial processing of complex organic substrates. Previous studies in forests and tundra ecosystems suggest patterns of substrate utilization and limitation are seasonal; above freezing, soil microbes access fresh litter inputs and sugar exudates from plant roots, while under frozen condition they recycle nutrients incorporated in microbial biomass. In order to liberate nutrients required for carbon degradation, soil microbes invest energy in the production of extracellular enzymes that cleave monomers from polymer bonds. The inverse relationship between relative enzyme abundance and substrate availability makes enzyme assays a useful proxy to assess changes in resources over time. Our objective in this study was to assess patterns in microbial biomass, nutrient availability, and extracellular enzyme activity in four snow exclosure sites over a seven-month period. Over the past three years, we have maintained a snow removal experiment on two restored prairies in central Minnesota. In each prairie, snow was continuously removed annually from two 4 x 4 m plots by shoveling after each snow event. Extractable C, N and P, and microbial C, N and P in soil samples were measured in samples collected from these snow removal plots, as well as in adjacent unmanipulated prairie control plots. Pools of C, N, and P were estimated using standard extraction protocols, and microbial pools were estimated using chloroform fumigation direct extraction (CFDE). We conducted fluorometric extracellular enzyme assays (EEA) to assess how the degradation potential of cellulose (cellobiohydrolase, CBH), protein (leucine aminopeptidase, LAP), and phosphate esters (phosphatase, PHOS) changed seasonally. Microbial C and N declined between October and June, while microbial P declined during the fall and winter, but increased

  3. Exogenous methyl jasmonate treatment increases glucosinolate biosynthesis and quinone reductase activity in kale leaf tissue.

    PubMed

    Ku, Kang-Mo; Jeffery, Elizabeth H; Juvik, John A

    2014-01-01

    Methyl jasmonate (MeJA) spray treatments were applied to the kale varieties 'Dwarf Blue Curled Vates' and 'Red Winter' in replicated field plantings in 2010 and 2011 to investigate alteration of glucosinolate (GS) composition in harvested leaf tissue. Aqueous solutions of 250 µM MeJA were sprayed to saturation on aerial plant tissues four days prior to harvest at commercial maturity. The MeJA treatment significantly increased gluconasturtiin (56%), glucobrassicin (98%), and neoglucobrassicin (150%) concentrations in the apical leaf tissue of these genotypes over two seasons. Induction of quinone reductase (QR) activity, a biomarker for anti-carcinogenesis, was significantly increased by the extracts from the leaf tissue of these two cultivars. Extracts of apical leaf tissues had greater MeJA mediated increases in phenolics, glucosinolate concentrations, GS hydrolysis products, and QR activity than extracts from basal leaf tissue samples. The concentration of the hydrolysis product of glucoraphanin, sulforphane was significantly increased in apical leaf tissue of the cultivar 'Red Winter' in both 2010 and 2011. There was interaction between exogenous MeJA treatment and environmental conditions to induce endogenous JA. Correlation analysis revealed that indole-3-carbanol (I3C) generated from the hydrolysis of glucobrassicin significantly correlated with QR activity (r = 0.800, P<0.001). Concentrations required to double the specific QR activity (CD values) of I3C was calculated at 230 µM, which is considerably weaker at induction than other isothiocyanates like sulforphane. To confirm relationships between GS hydrolysis products and QR activity, a range of concentrations of MeJA sprays were applied to kale leaf tissues of both cultivars in 2011. Correlation analysis of these results indicated that sulforaphane, NI3C, neoascorbigen, I3C, and diindolylmethane were all significantly correlated with QR activity. Thus, increased QR activity may be due to combined

  4. Novel methyl transfer during chemotaxis in Bacillus subtilis

    SciTech Connect

    Thoelke, M.S.; Kirby, J.R.; Ordal, G.W. )

    1989-06-27

    If Bacillus subtilis is incubated in radioactive methionine in the absence of protein synthesis, the methyl-accepting chemotaxis proteins (MCPs) become radioactively methylated. If the bacteria are further incubated in excess nonradioactive methionine (cold-chased) and then given the attractant aspartate, the MCPs lose about half of their radioactivity due to turnover, in which lower specific activity methyl groups from S-adenosylmethionine (AdoMet) replace higher specific activity ones. Due to the cold-chase, the specific activity of the AdoMet pool is reduced at least 2-fold. If, later, the attractant is removed, higher specific activity methyl groups return to the MCPs. Thus, there must exist an unidentified methyl carrier than can reversibly receive methyl groups from the MCPs. In a similar experiment, labeled cells were transferred to a flow cell and exposed to addition and removal of attractant and of repellent. All four kinds of stimuli were found to cause methanol production. Bacterial with maximally labeled MCPs were exposed to many cycles of addition and removal of attractant; the maximum amount of radioactive methanol was evolved on the third, not the first, cycle. This result suggests that there is a precursor-product relationship between methyl groups on the MCPs and on the unidentified carrier, which might be the direct source of methanol. However, since no methanol was produced when a methyltransferase mutant, whose MCPs were unmethylated, was exposed to addition and removal of attractant or repellent, the methanol must ultimately derive from methylated MCPs.

  5. N-methyl-D-aspartate antagonist activity of alpha- and beta-sulfallorphans.

    PubMed

    Shukla, V K; Lemaire, S

    1997-01-01

    Resolved equatorial (alpha) and axial (beta) forms of S-allylmorphinans, alpha-sulfallorphan and beta-sulfallorphan, were tested for their ability to compete with the binding of phencyclidine and sigma receptor ligands to mouse brain membranes and to antagonize N-methyl-D-aspartate (NMDA)-induced convulsions in mice. alpha- and beta-sulfallorphans displayed distinct binding affinities for phencyclidine and sigma sites, inhibiting the binding of [3H]-(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten++ +-5, 10-imine ([3H]MK-801) with Ki values of 2.32 and 0.13 microM and that of [3H](+)-pentazocine with Ki values of 1.97 and 1.61 microM, respectively. Intracerebroventricular administration of these compounds in mice caused dose-dependent inhibitions of NMDA-induced convulsions, but did not affect convulsions induced by (R,S)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), kainic acid and bicuculline. alpha- and beta-sulfallorphans blocked the convulsive activity of NMDA (1 nmol/mouse; intracerebroventricular) with ED50 values of 0.48 and 0.015 nmol/mouse, as compared with 0.55, 0.039 and 0.013 nmol/mouse for dextrorphan, MK-801 and (+/-)3-(2-carboxypiperazine-4yl)propyl-1-proprionic acid, respectively. The structurally related compound, dextrallorphan, significantly but less potently blocked NMDA-induced convulsions (ED60, 2.68 nmol/mouse). At the protective doses, alpha- and beta-sulfallorphans markedly reduced NMDA- and AMPA-induced mortality without inducing locomotion and falling behavior. These results indicate that alpha- and beta-sulfallorphans are potent and selective NMDA antagonists devoid of motor side effects at protective doses.

  6. Effects of Catechol O-Methyl Transferase Inhibition on Anti-Inflammatory Activity of Luteolin Metabolites.

    PubMed

    Ha, Sang Keun; Lee, Jin-Ah; Cho, Eun Jung; Choi, Inwook

    2017-02-01

    Although luteolin is known to have potent anti-inflammatory activities, much less information has been provided on such activities of its hepatic metabolites. Luteolin was subjected to hepatic metabolism in HepG2 cells either without or with catechol O-methyl transferase (COMT) inhibitor. To identify hepatic metabolites of luteolin without (luteolin metabolites, LMs) or with COMT inhibitor (LMs+CI), metabolites were treated by β-glucuronidase and sulfatase, and found that they were composed of glucuronide and sulfate conjugates of diosmetin in LMs or these conjugates of luteolin in LMs+CI. LMs and LMs+CI were examined for their anti-inflammatory activities on LPS stimulated Raw 264.7 cells. Expression of iNOS and production of nitric oxide and pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6 were suppressed more effectively by the treatment with LMs+CI than LMs. Our data provide a new insight on possible improvement in functional properties of luteolin on target cells by modifying their metabolic pathway in hepatocytes.

  7. Phosphatidylinositol 3-Kinase Promotes Activation and Vacuolar Acidification and Delays Methyl Jasmonate-Induced Leaf Senescence.

    PubMed

    Liu, Jian; Ji, Yingbin; Zhou, Jun; Xing, Da

    2016-03-01

    PI3K and its product PI3P are both involved in plant development and stress responses. In this study, the down-regulation of PI3K activity accelerated leaf senescence induced by methyl jasmonate (MeJA) and suppressed the activation of vacuolar H(+)-ATPase (V-ATPase). Yeast two-hybrid analyses indicated that PI3K bound to the V-ATPase B subunit (VHA-B). Analysis of bimolecular fluorescence complementation in tobacco guard cells showed that PI3K interacted with VHA-B2 in the tonoplasts. Through the use of pharmacological and genetic tools, we found that PI3K and V-ATPase promoted vacuolar acidification and stomatal closure during leaf senescence. Vacuolar acidification was suppressed by the PIKfyve inhibitor in 35S:AtVPS34-YFP Arabidopsis during MeJA-induced leaf senescence, but the decrease was lower than that in YFP-labeled Arabidopsis. These results suggest that PI3K promotes V-ATPase activation and consequently induces vacuolar acidification and stomatal closure, thereby delaying MeJA-induced leaf senescence.

  8. Testing Iodized Activated Carbon Filters with Non-Radio Active Methyl Iodide.

    DTIC Science & Technology

    1980-05-30

    and 4314, 4315, and 4316 are labora- to y impregnations using KI, KIO 3, hexamethylenetetramine and a pH 10 phosphate buffer (11). The agreement...14, Columbia Activated Carbon 207A 8 x 16, Sutcliffe, Speakman Co. Ltd. BPL 8 x 20, Activated Carbon Division, Calgon Corp. KITEG II Nuclear Consulting Services, Inc. TEDA triethylenediamine HMTA hexamethylenetetramine 52

  9. Mercury cycling in agricultural and managed wetlands of California: seasonal influences of vegetation on mercury methylation, storage, and transport

    USGS Publications Warehouse

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Kakouros, Evangelos; Agee, Jennifer L.; Kieu, Le H.; Stricker, Craig A.; Fleck, Jacob A.; Ackerman, Joshua T.

    2013-01-01

    Plants are a dominant biologic and physical component of many wetland capable of influencing the internal pools and fluxes of methylmercury (MeHg). To investigate their role with respect to the latter, we examined the changing seasonal roles of vegetation biomass and Hg, C and N composition from May 2007-February 2008 in 3 types of agricultural wetlands (domesticated or white rice, wild rice, and fallow fields), and in adjacent managed natural wetlands dominated by cattail and bulrush (tule). We also determined the impact of vegetation on seasonal microbial Hg methylation rates, and Hg and MeHg export via seasonal storage in vegetation, and biotic consumption of rice seed. Despite a compressed growing season of ~ 3 months, annual net primary productivity (NPP) was greatest in white rice fields and carbon more labile (leaf median C:N ratio = 27). Decay of senescent litter (residue) was correlated with microbial MeHg production in winter among all wetlands. As agricultural biomass accumulated from July to August, THg concentrations declined in leaves but MeHg concentrations remained consistent, such that MeHg pools generally increased with growth. Vegetation provided a small, temporary, but significant storage term for MeHg in agricultural fields when compared with hydrologic export. White rice and wild rice seeds reached mean MeHg concentrations of 4.1 and 6.2 ng gdw- 1, respectively. In white rice and wild rice fields, seed MeHg concentrations were correlated with root MeHg concentrations (r = 0.90, p < 0.001), suggesting transport of MeHg to seeds from belowground tissues. Given the proportionally elevated concentrations of MeHg in rice seeds, white and wild rice crops may act as a conduit of MeHg into biota, especially waterfowl which forage heavily on rice seeds within the Central Valley of California, USA. Thus, while plant tissues and rhizosphere soils provide temporary storage for MeHg during the growing season, export of MeHg is enhanced post-harvest through

  10. A spectrophotometric assay for the determination of 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase activity.

    PubMed

    Bernal, Cristobal; Mendez, Eva; Terencio, José; Boronat, Albert; Imperial, Santiago

    2005-05-15

    We report an assay for the determination of the activity of 4-diphosphocytidyl-2-C-methyl-D-erythritol kinase, the enzyme which catalyzes the fourth reaction step of the 2-C-methyl-D-erythritol 4-phosphate pathway for the synthesis of isoprenoids, which is based on the spectrophotometrical determination of adenosine 5'-diphosphate using pyruvate kinase and L-lactate dehydrogenase as auxiliary enzymes. This method can be adapted to microtiter plates, can be automated, and because of its simplicity and speed can be useful for the functional characterization of the enzyme and for the screening of inhibitors with potential antibiotic or antimalarial action.

  11. Asymmetric behavior of different solar activity features over solar cycles 20-23

    NASA Astrophysics Data System (ADS)

    Bankoti, Neeraj Singh; Joshi, Navin Chandra; Pande, Bimal; Pande, Seema; Uddin, Wahab; Pandey, Kavita

    2011-07-01

    This paper presents the study of normalized north-south asymmetry, cumulative normalized north-south asymmetry and cumulative difference indices of sunspot areas, solar active prominences (at total, low (⩽40°) and high (⩾50°) latitudes) and H α solar flares from 1964 to 2008 spanning the solar cycles 20-23. Three different statistical methods are used to obtain the asymmetric behavior of different solar activity features. Hemispherical distribution of activity features shows the dominance of activities in northern hemisphere for solar cycle 20 and in southern hemisphere for solar cycles 21-23 excluding solar active prominences at high latitudes. Cumulative difference index of solar activity features in each solar cycle is observed at the maximum of the respective solar cycle suggesting a cyclic behavior of approximately one solar cycle length. Asymmetric behavior of all activity features except solar active prominences at high latitudes hints at the long term periodic trend of eight solar cycles. North-south asymmetries of SAP (H) express the specific behavior of solar activity at high solar latitudes and its behavior in long-time scale is distinctly opposite to those of other activity features. Our results show that in most cases the asymmetry is statistically highly significant meaning thereby that the asymmetries are real features in the N-S distribution of solar activity features.

  12. Destruction of methyl bromide sorbed to activated carbon by thiosulfate and electrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl bromide is widely used as a fumigant for post-harvest and quarantine uses at port facilities due to the low treatment times required, but it is vented to the atmosphere after its use. Due to the potential contributions of methyl bromide to stratospheric ozone depletion, technologies for the c...

  13. Structure related effects of flavonoid aglycones on cell cycle progression of HepG2 cells: Metabolic activation of fisetin and quercetin by catechol-O-methyltransferase (COMT).

    PubMed

    Poór, Miklós; Zrínyi, Zita; Kőszegi, Tamás

    2016-10-01

    Dietary flavonoids are abundant in the Plant Kingdom and they are extensively studied because of their manifold pharmacological activities. Recent studies highlighted that cell cycle arrest plays a key role in their antiproliferative effect in different tumor cells. However, structure-activity relationship of flavonoids is poorly characterized. In our study the influence of 18 flavonoid aglycones (as well as two metabolites) on cell cycle distribution was investigated. Since flavonoids are extensively metabolized by liver cells, HepG2 tumor cell line was applied, considering the potential metabolic activation/inactivation of flavonoids. Our major observations are the followings: (1) Among the tested compounds diosmetin, fisetin, apigenin, lutelin, and quercetin provoked spectacular extent of G2/M phase cell cycle arrest. (2) Inhibition of catechol-O-methyltransferase enzyme by entacapone decreased the antiproliferative effects of fisetin and quercetin. (3) Geraldol and isorhamnetin (3'-O-methylated metabolites of fisetin and quercetin, respectively) demonstrated significantly higher antiproliferative effect on HepG2 cells compared to the parent compounds. Based on these results, O-methylated flavonoid metabolites or their chemically modified derivatives may be suitable candidates of tumor therapy in the future.

  14. Teaching Ecosystems and Matter Cycles with Creative Drama Activities

    ERIC Educational Resources Information Center

    Cokadar, Hulusi; Yilmaz, Gulcin Cihan

    2010-01-01

    The purpose of this study is to examine the effect of creative drama-based instruction on seventh graders' science achievements in the ecology and matter cycles unit and their attitudes toward science. The study is an experimental study carried out in one of the public elementary schools in Turkey during 2005-2006 schooling year. An ecological…

  15. Effect of Pd surface structure on the activation of methyl acetate

    SciTech Connect

    Xu, Lijun; Xu, Ye

    2011-01-01

    The activation of methyl acetate (CH3COOCH3; MA) has been studied using periodic density functional theory calculations to probe the effect of Pd surface structure on the selectivity in MA activation. The adsorption of MA, dehydrogenated derivatives, enolate (CH2COOCH3; ENL) and methylene acetate (CH3COOCH2; MeA), and several dissociation products (including acetate, acetyl, ketene, methoxy, formaldehyde, CO, C, O, and H); and C-H and C-O (mainly in the RCO-OR position) bond dissociation in MA, ENL, and MeA, are calculated on Pd(111) terrace, step, and kink; and on Pd(100) terrace and step. The adsorption of most species is not strongly affected between (111)- to (100)-type surfaces, but is clearly enhanced by step/kink compared to the corresponding terrace. Going from terrace to step edge and from (111)- to (100)-type surfaces both stabilize the transition states of C-O bond dissociation steps. Going from terrace to step edge also stabilizes the transition states of C-H bond dissociation steps, but going from (111)- to (100)-type surfaces does not clearly do so. We propose that compared to the Pd(111) terrace, the Pd(100) terrace is more selective for C-O bond dissociation that is desirable for alcohol formation, whereas the Pd step edges are more selective for C-H bond dissociation.

  16. Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models

    SciTech Connect

    Saeed, Noha M.; El-Demerdash, Ebtehal; Abdel-Rahman, Hanaa M.; Algandaby, Mardi M.; Al-Abbasi, Fahad A.; Abdel-Naim, Ashraf B.

    2012-10-01

    Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ► Efficacy of MP and EP in combating inflammation was displayed in several models. ► MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ► MP and EP decreased TNF-α and IL-6 levels in experimental endotoxemia. ► MP and EP reduced NF-κB expression and histological changes in rat liver and lung. ► MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.

  17. Heat-activated persulfate oxidation of methyl- and ethyl-parabens: Effect, kinetics, and mechanism.

    PubMed

    Chen, Yiqun; Deng, Pinya; Xie, Pengchao; Shang, Ran; Wang, Zongping; Wang, Songlin

    2017-02-01

    We evaluated the degradation of methylparaben (MeP) and ethylparaben (EtP), two representative parabens, using the heat-activated persulfate system in a laboratory. Both sulfate and hydroxyl radicals contributed to the removal of the two parabens. The degradations of both MeP and EtP were improved by increasing the heating temperature or persulfate dose in accordance with a pseudo-first-order reaction model. The oxidation efficiency of parabens was found to be pH-dependent; decreasing in the order pH 5.0 > 7.0 > 9.0. The presence of chloride, bicarbonate, or humic acid was found to inhibit the degradation of the two parabens to some extent because of competition for the reactive radicals, with humic acid having the most serious effect. Dealkylation of the methyl unit, decarboxylation of the carboxylic group, and subsequent hydrolysis are proposed to be involved in the degradation pathway of MeP. The results suggest that the heat-activated persulfate system might be efficiently applied in the treatment of paraben-containing water samples. This was also supported by the results of applying this system to treat a real water sample containing both MeP and EtP.

  18. The effect of methyl-donated hydrogen bonding on active site conformations of hyaluronate lyase

    NASA Astrophysics Data System (ADS)

    Migues, Angela N.; Vergenz, Robert A.; Moore, Kevin B.

    2010-03-01

    Geometric evidence shows a val-A252 methyl-donated (MD) hydrogen bond (HB) in hyaluronate lyase (Streptococcus pneumoniae) interacts with nearby NH--O and OH--O HBs, distorting active-site helical structure. Results for model fragment A248-254 are based on experimental heavy atom positions with ab initio hydrogen atoms. The MDHB, with (H-O distance, donor-H-O angle) = (2.3å; 174^o), exhibits more favorable geometry than thr-A253 OH--O HB (1.8å; 170^o) to the same ala-249 C=O. Consequently, thr-253 N-H--O interaction is forced closer to lys-250 C=O than ala-249 C=O(2.6 versus 2.7å). A novel method has been developed to quantify the effects of atomic diplacements on motions of neighboring helices. A coordinate system was established to track the movement of specific residues and to ascertain the effect of such motions on active site conformations.

  19. Adsorption of doxorubicin on poly(methyl methacrylate)-chitosan-heparin-coated activated carbon beads.

    PubMed

    Miao, Jianjun; Zhang, Fuming; Takieddin, Majde; Mousa, Shaker; Linhardt, Robert J

    2012-03-06

    Extracorporeal filter cartridges, filled with an activated carbon bead (ACB) adsorbent, have been used for removal of overdosed cancer drugs from the blood. Coatings on adsorbent matrices, poly(methyl methacrylate) (PMMA)/activated carbon bead and PMMA/chitosan/heparin/ACB composites, were tested to improve their biocompatibility and blood compatibility. PMMA coating on ACBs was accomplished in a straightforward manner using a PMMA solution in ethyl acetate. A one-step hybrid coating of ACBs with PMMA-anticoagulant heparin required the use of acetone and water co-solvents. Multilayer coatings with three components, PMMA, chitosan, and heparin, involved three steps: PMMA was first coated on ACBs; chitosan was then coated on the PMMA-coated surface; and finally, heparin was covalently attached to the chitosan coating. Surface morphologies were studied by scanning electron microscopy. X-ray photoelectron spectroscopy confirmed the -SO(3)(-) group. Adsorption, of a chemotherapy drug (doxorubicin) from both water and phosphate-buffered saline, by the coated ACBs was examined. The adsorption isotherm curves were fitted using the Freundlich model. The current adsorption system might find potential applications in the removal of high-dose regional chemotherapy drugs while maintaining high efficiency, biocompatibility, and blood compatibility.

  20. Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models.

    PubMed

    Saeed, Noha M; El-Demerdash, Ebtehal; Abdel-Rahman, Hanaa M; Algandaby, Mardi M; Al-Abbasi, Fahad A; Abdel-Naim, Ashraf B

    2012-10-01

    Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models.

  1. An N-methyl-d-aspartate receptor channel blocker with neuroprotective activity

    PubMed Central

    Tai, Kwok-Keung; Blondelle, Sylvie E.; Ostresh, John M.; Houghten, Richard A.; Montal, Mauricio

    2001-01-01

    Excitotoxicity, resulting from sustained activation of glutamate receptors of the N-methyl-d-aspartate (NMDA) subtype, is considered to play a causative role in the etiology of ischemic stroke and several neurodegenerative diseases. The NMDA receptor is therefore a target for the development of neuroprotective agents. Here, we identify an N-benzylated triamine (denoted as NBTA) as a highly selective and potent NMDA-receptor channel blocker selected by screening a reduced dipeptidomimetic synthetic combinatorial library. NBTA blocks recombinant NMDA receptors expressed in Xenopus laevis oocytes with a mean IC50 of 80 nM; in contrast, it does not block GluR1, a glutamate receptor of the non-NMDA subtype. The blocking activity of NBTA on NMDA receptors exhibits the characteristics of an open-channel blocker: (i) no competition with agonists, (ii) voltage dependence, and (iii) use dependence. Significantly, NBTA protects rodent hippocampal neurons from NMDA receptor, but not kainate receptor-mediated excitotoxic cell death, in agreement with its selective action on the corresponding recombinant receptors. Mutagenesis data indicate that the N site, a key asparagine on the M2 transmembrane segment of the NR1 subunit, is the main determinant of the blocker action. The results highlight the potential of this compound as a neuroprotectant. PMID:11248110

  2. Methyl jasmonate affects morphology, number and activity of endoplasmic reticulum bodies in Raphanus sativus root cells.

    PubMed

    Gotté, Maxime; Ghosh, Rajgourab; Bernard, Sophie; Nguema-Ona, Eric; Vicré-Gibouin, Maïté; Hara-Nishimura, Ikuko; Driouich, Azeddine

    2015-01-01

    The endoplasmic reticulum (ER) bodies are ER-derived structures that are found in Brassicaceae species and thought to play a role in defense. Here, we have investigated the occurrence, distribution and function of ER bodies in root cells of Raphanus sativus using a combination of microscopic and biochemical methods. We have also assessed the response of ER bodies to methyl jasmonate (MeJA), a phytohormone that mediates plant defense against wounding and pathogens. Our results show that (i) ER bodies do occur in different root cell types from the root cap region to the differentiation zone; (ii) they do accumulate a PYK10-like protein similar to the major marker protein of ER bodies that is involved in defense in Arabidopsis thaliana; and (iii) treatment of root cells with MeJA causes a significant increase in the number of ER bodies and the activity of β-glucosidases. More importantly, MeJA was found to induce the formation of very long ER bodies that results from the fusion of small ones, a phenomenon that has not been reported in any other study so far. These findings demonstrate that MeJA impacts the number and morphology of functional ER bodies and stimulates ER body enzyme activities, probably to participate in defense responses of radish root. They also suggest that these structures may provide a defensive system specific to root cells.

  3. Exogenous methyl jasmonate regulates cytokinin content by modulating cytokinin oxidase activity in wheat seedlings under salinity.

    PubMed

    Avalbaev, Azamat; Yuldashev, Ruslan; Fedorova, Kristina; Somov, Kirill; Vysotskaya, Lidiya; Allagulova, Chulpan; Shakirova, Farida

    2016-02-01

    The treatment of 4-days-old wheat seedlings with methyl jasmonate (MeJA) in concentration optimal for their growth (0.1 μM) resulted in a rapid transient almost two-fold increase in the level of cytokinins (CKs). MeJA-induced accumulation of CKs was due to inhibition of both cytokinin oxidase (CKX) (cytokinin oxidase/dehydrogenase, EC 1.5.99.12) gene expression and activity of this enzyme. Pretreatment of wheat seedlings with MeJA decreased the growth-retarding effect of sodium chloride salinity and accelerated growth recovery after withdrawal of NaCl from the incubation medium. We speculate that this protective effect of the hormone might be due to MeJA's ability to prevent the salinity-induced decline in CK concentration that was caused by inhibition of gene expression and activity of CKX in wheat seedlings. The data might indicate an important role for endogenous cytokinins in the implementation of growth-promoting and protective effects of exogenous MeJA application on wheat plants.

  4. Tubulin dynamics during the cytoplasmic cohesiveness cycle in artificially activated sea urchin eggs.

    PubMed

    Coffe, G; Foucault, G; Raymond, M N; Pudles, J

    1983-12-01

    Sedimentation studies and [3H]colchicine-binding assays have demonstrated a relationship between the cytoplasmic cohesiveness cycles and the changes in tubulin organization in Paracentrotus lividus eggs activated by 2.5 mM procaine. The same amount of tubulin (20-25% of the total egg tubulin) is involved in these cyclic process and appears to undergo polymerization and depolymerization cycles. Electron microscopy studies reveal that the microtubules formed during these cytoplasmic cohesiveness cycles are under a particulate form which is sedimentable at low speed. Activation experiments carried out in the presence of cytochalasin B (CB) show that the increase in the cytoplasmic cohesiveness is highly reduced while tubulin polymerization and depolymerization cycles and pronuclear centration are not affected. Although tubulin or actin polymerization can be independently triggered in procaine-activated eggs, the increase in cytoplasmic cohesiveness requires the polymerization of both proteins. However, the cytoplasmic cohesiveness cycles appear to be regulated by tubulin polymerization and depolymerization cycles.

  5. Computational Simulation of the Activation Cycle of Gα Subunit in the G Protein Cycle Using an Elastic Network Model

    PubMed Central

    Kim, Min Hyeok; Kim, Young Jin; Kim, Hee Ryung; Jeon, Tae-Joon; Choi, Jae Boong; Chung, Ka Young; Kim, Moon Ki

    2016-01-01

    Agonist-activated G protein-coupled receptors (GPCRs) interact with GDP-bound G protein heterotrimers (Gαβγ) promoting GDP/GTP exchange, which results in dissociation of Gα from the receptor and Gβγ. The GTPase activity of Gα hydrolyzes GTP to GDP, and the GDP-bound Gα interacts with Gβγ, forming a GDP-bound G protein heterotrimer. The G protein cycle is allosterically modulated by conformational changes of the Gα subunit. Although biochemical and biophysical methods have elucidated the structure and dynamics of Gα, the precise conformational mechanisms underlying the G protein cycle are not fully understood yet. Simulation methods could help to provide additional details to gain further insight into G protein signal transduction mechanisms. In this study, using the available X-ray crystal structures of Gα, we simulated the entire G protein cycle and described not only the steric features of the Gα structure, but also conformational changes at each step. Each reference structure in the G protein cycle was modeled as an elastic network model and subjected to normal mode analysis. Our simulation data suggests that activated receptors trigger conformational changes of the Gα subunit that are thermodynamically favorable for opening of the nucleotide-binding pocket and GDP release. Furthermore, the effects of GTP binding and hydrolysis on mobility changes of the C and N termini and switch regions are elucidated. In summary, our simulation results enabled us to provide detailed descriptions of the structural and dynamic features of the G protein cycle. PMID:27483005

  6. Methyl syringate, a low-molecular-weight phenolic ester, as an activator of the chemosensory ion channel TRPA1.

    PubMed

    Son, Hee Jin; Kim, Min Jung; Park, Jae-Ho; Ishii, Sho; Misaka, Takumi; Rhyu, Mee-Ra

    2012-12-01

    Transient receptor potential channel ankryn 1 (TRPA1) and transient receptor potential channel vanilloid 1 (TRPV1) are members of the TRP superfamily of structurally related, nonselective cation channels and are often coexpressed in sensory neurons. Extracts of the first leaves of Kalopanax pictus Nakai (Araliaceae) have been shown to activate hTRPA1 and hTRPV1. Therefore, the effects of six commercially available chemicals (methyl syringate, coniferyl alcohol, protocatechuic acid, hederacoside C, α-hederin, and eleutheroside B) found in K. pictus were investigated on cultured cells expressing hTRPA1 and hTRPV1. Of the six compounds, methyl syringate selectively activated hTRPA1 (EC(50) = 507.4 μM), but not hTRPV1. Although methyl syringate had a higher EC(50) compared with allyl isothiocyanate (EC(50) = 7.4 μM) and cinnamaldehyde (EC(50) = 22.2 μM), the present study provides evidence that methyl syringate from K. pictus is a specific and selective activator of hTRPA1.

  7. Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles

    PubMed Central

    BURAL, Canan; AKTAŞ, Esin; DENIZ, Günnur; ÜNLÜÇERÇI, Yeşim; BAYRAKTAR, Gülsen

    2011-01-01

    Objectives Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. Material and Methods A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05). Results [MMA]r was significantly (p≤0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. Conclusion Due to reduction of leaching residual MMA concentrations, use of terminal boiling in the

  8. Fibrillarin methylates H2A in RNA polymerase I trans-active promoters in Brassica oleracea

    PubMed Central

    Loza-Muller, Lloyd; Rodríguez-Corona, Ulises; Sobol, Margarita; Rodríguez-Zapata, Luis C.; Hozak, Pavel; Castano, Enrique

    2015-01-01

    Fibrillarin is a well conserved methyltransferase involved in several if not all of the more than 100 methylations sites in rRNA which are essential for proper ribosome function. It is mainly localized in the nucleoli and Cajal bodies inside the cell nucleus where it exerts most of its functions. In plants, fibrillarin binds directly the guide RNA together with Nop56, Nop58, and 15.5ka proteins to form a snoRNP complex that selects the sites to be methylated in pre-processing of ribosomal RNA. Recently, the yeast counterpart NOP1 was found to methylate histone H2A in the nucleolar regions. Here we show that plant fibrillarin can also methylate histone H2A. In Brassica floral meristem cells the methylated histone H2A is mainly localized in the nucleolus but unlike yeast or human cells it also localize in the periphery of the nucleus. In specialized transport cells the pattern is altered and it exhibits a more diffuse staining in the nucleus for methylated histone H2A as well as for fibrillarin. Here we also show that plant fibrillarin is capable of interacting with H2A and carry out its methylation in the rDNA promoter. PMID:26594224

  9. Performance improvement: an active life cycle product management

    NASA Astrophysics Data System (ADS)

    Cucchiella, Federica; Gastaldi, Massimo; Lenny Koh, S. C.

    2010-03-01

    The management of the supply chain has gained importance in many manufacturing firms. Operational flexibility can be considered a crucial weapon to increase competitiveness in a turbulent marketplace. It reflects the ability of a firm to properly and rapidly respond to a variable and dynamic environment. For the firm operating in a fashion sector, the management of the supply chain is even more complex because the product life cycle is shorter than that of the firm operating in a non-fashion sector. The increase of firm flexibility level can be reached through the application of the real option theory inside the firm network. In fact, real option may increase the project value by allowing managers to more efficiently direct the production. The real option application usually analysed in literature does not take into account that the demands of products are well-defined by the product life cycle. Working on a fashion sector, the life cycle pattern is even more relevant because of an expected demand that grows according to a constant rate that does not capture the demand dynamics of the underlying fashion goods. Thus, the primary research objective of this article is to develop a model useful for the management of investments in a supply chain operating in a fashion sector where the system complexity is increased by the low level of unpredictability and stability that is proper of the mood phenomenon. Moreover, unlike the traditional model, a real option framework is presented here that considers fashion product characterised by uncertain stages of the production cycle.

  10. Prediction of solar activity from solar background magnetic field variations in cycles 21-23

    SciTech Connect

    Shepherd, Simon J.; Zharkov, Sergei I.; Zharkova, Valentina V. E-mail: s.zharkov@hull.ac.uk

    2014-11-01

    A comprehensive spectral analysis of both the solar background magnetic field (SBMF) in cycles 21-23 and the sunspot magnetic field in cycle 23 reported in our recent paper showed the presence of two principal components (PCs) of SBMF having opposite polarity, e.g., originating in the northern and southern hemispheres, respectively. Over a duration of one solar cycle, both waves are found to travel with an increasing phase shift toward the northern hemisphere in odd cycles 21 and 23 and to the southern hemisphere in even cycle 22. These waves were linked to solar dynamo waves assumed to form in different layers of the solar interior. In this paper, for the first time, the PCs of SBMF in cycles 21-23 are analyzed with the symbolic regression technique using Hamiltonian principles, allowing us to uncover the underlying mathematical laws governing these complex waves in the SBMF presented by PCs and to extrapolate these PCs to cycles 24-26. The PCs predicted for cycle 24 very closely fit (with an accuracy better than 98%) the PCs derived from the SBMF observations in this cycle. This approach also predicts a strong reduction of the SBMF in cycles 25 and 26 and, thus, a reduction of the resulting solar activity. This decrease is accompanied by an increasing phase shift between the two predicted PCs (magnetic waves) in cycle 25 leading to their full separation into the opposite hemispheres in cycle 26. The variations of the modulus summary of the two PCs in SBMF reveals a remarkable resemblance to the average number of sunspots in cycles 21-24 and to predictions of reduced sunspot numbers compared to cycle 24: 80% in cycle 25 and 40% in cycle 26.

  11. Exogenous Methyl Jasmonate Treatment Increases Glucosinolate Biosynthesis and Quinone Reductase Activity in Kale Leaf Tissue

    PubMed Central

    Ku, Kang-Mo; Jeffery, Elizabeth H.; Juvik, John A.

    2014-01-01

    Methyl jasmonate (MeJA) spray treatments were applied to the kale varieties ‘Dwarf Blue Curled Vates’ and ‘Red Winter’ in replicated field plantings in 2010 and 2011 to investigate alteration of glucosinolate (GS) composition in harvested leaf tissue. Aqueous solutions of 250 µM MeJA were sprayed to saturation on aerial plant tissues four days prior to harvest at commercial maturity. The MeJA treatment significantly increased gluconasturtiin (56%), glucobrassicin (98%), and neoglucobrassicin (150%) concentrations in the apical leaf tissue of these genotypes over two seasons. Induction of quinone reductase (QR) activity, a biomarker for anti-carcinogenesis, was significantly increased by the extracts from the leaf tissue of these two cultivars. Extracts of apical leaf tissues had greater MeJA mediated increases in phenolics, glucosinolate concentrations, GS hydrolysis products, and QR activity than extracts from basal leaf tissue samples. The concentration of the hydrolysis product of glucoraphanin, sulforphane was significantly increased in apical leaf tissue of the cultivar ‘Red Winter’ in both 2010 and 2011. There was interaction between exogenous MeJA treatment and environmental conditions to induce endogenous JA. Correlation analysis revealed that indole-3-carbanol (I3C) generated from the hydrolysis of glucobrassicin significantly correlated with QR activity (r = 0.800, P<0.001). Concentrations required to double the specific QR activity (CD values) of I3C was calculated at 230 µM, which is considerably weaker at induction than other isothiocyanates like sulforphane. To confirm relationships between GS hydrolysis products and QR activity, a range of concentrations of MeJA sprays were applied to kale leaf tissues of both cultivars in 2011. Correlation analysis of these results indicated that sulforaphane, NI3C, neoascorbigen, I3C, and diindolylmethane were all significantly correlated with QR activity. Thus, increased QR activity may be due to

  12. Rapid Synthesis and Antiviral Activity of (Quinazolin-4-Ylamino)Methyl-Phosphonates Through Microwave Irradiation

    PubMed Central

    Luo, Hui; Hu, Deyu; Wu, Jian; He, Ming; Jin, Linhong; Yang, Song; Song, Baoan

    2012-01-01

    This study describes the simple synthesis of new (quinazolin-4-ylamino) methylphosphonates via microwave irradiation. Substituted-2-aminobenzonitrile reacted with 1,1-dimethoxy-N,N-dimethylmethanamine at a reflux condition to obtain N′-(substituted-2-cyanophenyl)-N,N-dimethylformamidine (1). The subsequent reaction of this intermediate product with α-aminophosphonate (2) in a solution containing glacial acetic acid in 2-propanol through microwave irradiation resulted in the formation of (quinazolin-4-ylamino)methyl-phosphonate derivatives 3a to 3x, which were unequivocally characterized by the spectral data and elemental analysis. The influence of the reaction conditions on the yield of 3a was investigated to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 3a include a 1:1 molar ratio of N′-(2-cyanophenyl)-N,N-dimethylformamidine to diethyl amino(phenyl)methylphosphonate and a 4:1 volume ratio of isopropanol to HOAc in the solvent mixture, at a reaction temperature of 150 °C, with a microwave power of 100 W and a corresponding pressure of 150 psi for 20 min in the microwave synthesizer. The yield of 3a was approximately 79%, whereas those of 3b to 3x were approximately 77% to 86%. Some of the synthesized compounds displayed weak to good anti-Tobacco mosaic virus (TMV) activity. PMID:22837660

  13. Highly active ppm level organic copper catalyzed photo-induced ICAR ATRP of methyl methacrylate.

    PubMed

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-11-01

    A novel photo-induced homogeneous atom transfer radical polymerization (ATRP) system is constructed using an organic copper salt (Cu(SC(S)N(C2 H5 )2 )2 ) as a photo-induced catalyst at 30 °C. Herein, N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) is used as a ligand, ethyl 2-bromophenylacetate (EBPA) as an ATRP initiator, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) as a photo-induced radical initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP using methyl methacrylate (MMA) as a modal monomer. The effect of the concentration of the organic copper on the polymerization is investigated in detail. It is found that well-controlled polymerization can be obtained even with the amount of (Cu(SC(S)N(C2 H5 )2 )2 decreasing to a 1.56 ppm level, with the molecular weight of the resultant polymers increasing linearly with monomer conversion while maintaining a narrow molecular weight distribution (M¯w/M¯n < 1.3).

  14. Hepatoprotective effect of 7-Hydroxycoumarin against Methyl glyoxal toxicity via activation of Nrf2.

    PubMed

    Li, Dan; Wang, Na; Zhang, Jingdong; Ma, Shuren; Zhao, Zhuangzhuang; Ellis, Elizabeth M

    2017-03-02

    Methyl glyoxal (MG), a major precursor of advanced glycation end-products, has been identified as significant in the progression of several diseases including aging, diabetes and neurodegenerative diseases as well as causing hepatic damages. 7-hydroxycoumarin (7-HC), a natural-occurring derivative of coumarin from fruits and plants, has been reported to exert antioxidant and free radical-scavenging properties, protecting cells from aldehydes and oxidants. In this study, the ability of 7-HC to protect human HepG2 cells against MG-induced toxicity and oxidative stress was investigated. Results show that 7-HC pretreatment significantly attenuates MG-induced cytotoxicity, apoptotic changes and ROS accumulation and that this protection is shown to be associated with the induction of the nuclear factor erythroid 2-related factor 2 (NRF2) and its downstream detoxifying enzymes. In response to 7-HC, NRF2 protein translocates from cytosol to the nuclei. In addition, depletion of NRF2 by siRNA significantly reduces the protective effect of 7-HC against MG, suggesting that NRF2 plays an important role in the protective function of 7-HC. These findings highlight the potential for the interventional activation of the NRF2 induction via the non-toxic natural phytochemical 7-HC as a novel therapeutic approach towards the detoxification of MG, with the aim of halting the progression of diseases in which MG has been implicated.

  15. De novo DNA methylation of the paternal genome in 2-cell mouse embryos.

    PubMed

    Ma, X S; Wang, X G; Qin, L; Song, C L; Lin, F; Song, J M; Zhu, C C; Liu, H L

    2014-10-27

    The developmental dynamics of DNA methylation events have been well studied. Active demethylation of the paternal genome occurs in the zygote, passive demethylation occurs during cleavage stages, and de novo methylation occurs by the blastocyst stage. It is believed that the paternal genome has lower levels of methylation during early development than the maternal genome. However, in this study, we provide direct and indirect evidence of genome-wide de novo DNA methylation of the paternal genome after the first cell cycle in mouse embryos. Although very little methylation was detected within the male pronucleus in zygotes, an intense methylation signal was clearly visible within the androgenetic 2-cell embryos. Moreover, the DNA methylation level of the paternal genome in the post-zygotic metaphase embryos was similar to that of the maternal genome. Using indirect immunofluorescence with an antibody to methylated lysine 9 in histone H3, we provided new evidence to support the concept of spatial compartmentalization of parental genomes in 2-cell mouse embryos. Nevertheless, the transient segregation of parental genomes was not observed by determining the DNA methylation distribution in the 2-cell embryos even though DNA methylation asymmetry between the maternal and paternal pronucleus existed in the 1-cell stage. The disappearance of separate immunofluorescence signals of 5-methyl cytosine in the 2-cell embryos might be attributed to the de novo methylation of the paternal genome during the first mitotic cycle.

  16. THE ROLE OF VALENCE AND METHYLATION STATE ON THE ACTIVITY OF ARSENIC DURING MITOSIS

    EPA Science Inventory

    Trivalent methylated arsenicals are much more potent DNA damaging agents, clastogens, and large deletion mutagens than are their inorganic and pentavalent counterparts. Previously we had noticed that many of the arsenicals induced "c-type" anaphases characteristic of spindle pois...

  17. Labdanolic acid methyl ester (LAME) exerts anti-inflammatory effects through inhibition of TAK-1 activation

    SciTech Connect

    Cuadrado, Irene; Estevez-Braun, Ana; Heras, Beatriz de las

    2012-01-01

    Labdane derivatives obtained from the diterpenoid labdanediol suppressed NO and PGE{sub 2} production in LPS-stimulated RAW 264.7 macrophages. However, mechanisms involved in these inhibitory effects are not elucidated. In this study, we investigated the signaling pathways involved in the anti-inflammatory effects of labdanolic acid methyl ester (LAME) in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. LAME reduced the production of NO and PGE{sub 2} in LPS-activated macrophages. This effect involved the inhibition of NOS-2 and COX-2 gene expression, acting at the transcription level. Examination of the effects of the diterpene on NF-κB signaling showed that LAME inhibits the phosphorylation of IκBα and IκBβ, preventing their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signaling was also observed. A further experiment revealed that LAME inhibited the phosphorylation of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), an upstream signaling molecule required for IKK and mitogen-activated protein kinases (MAPKs) activation. Inflammatory cytokines such as IL-6, TNF-α and IP-10 were downregulated in the presence of this compound after stimulation with LPS. Additionally, LAME also improved survival in a mouse model of endotoxemia and reduced the circulatory levels of cytokines (IL-6, TNF-α). In conclusion, these results indicate that labdane diterpene LAME significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro. Highlights: ► LAME reduced the production of NO and PGE{sub 2} in LPS-activated macrophages. ► IL-6, TNF-α and IP-10 were also inhibited by LAME. ► Inhibition of TAK-1 activation is the mechanism involved in this process. ► LAME improved survival in a mouse model of endotoxemia. ► LAME reduced the circulatory levels of cytokines (IL-6, TNF-α).

  18. Comparison of changes in the global magnetic field and spot activity in cycles 21 to 24

    NASA Astrophysics Data System (ADS)

    Bilenko, I. A.

    2016-12-01

    We compare changes in the solar global magnetic field (GMF) given by the distribution of magnetic fields on the source surface and spot activity characterized by Wolf numbers, the number of spots, and their area reflecting the dynamics of local magnetic fields of active regions during cycles 21 to 24 (1976-2015). The results indicate that the changes in the GMF and spot activity have certain differences, both in different cycles generally and in the phases of growth, maximum, and decline in each individual cycle. The maximum and minimum correlations between the GMF and spot activity are observed in cycles 22 and 24, respectively. The maximum correlation is reached in growth phases (cycles 21, 22, and 24) and in the phase of decline (cycle 23), which can be associated with the fact that the phase of decline in cycle 23 is anomalously extended. Almost no correlation between the GMF and spot activity can be found at the phases of the maximum and early beginning of decline in all cycles. This can be associated with structural reorganization and sign change in the GMF.

  19. Respiratory Muscle Activity During Simultaneous Stationary Cycling and Inspiratory Muscle Training.

    PubMed

    Hellyer, Nathan J; Folsom, Ian A; Gaz, Dan V; Kakuk, Alynn C; Mack, Jessica L; Ver Mulm, Jacyln A

    2015-12-01

    Inspiratory muscle training (IMT) strengthens the muscles of respiration, improves breathing efficiency, and increases fitness. The IMT is generally performed independently of aerobic exercise; however, it is not clear whether there is added benefit of performing the IMT while simultaneously performing aerobic exercise in terms of activating and strengthening inspiratory muscles. The purpose of our study was to determine the effect of IMT on respiratory muscle electromyography (EMG) activity during stationary cycling in the upright and drops postures as compared with that when the IMT was performed alone. Diaphragm and sternocleidomastoid EMG activity was measured under different resting and cycling postures, with and without the use of the IMT at 40% maximal inspiratory pressure (n = 10; mean age 37). Cycling in an upright posture while simultaneously performing the IMT resulted in a significantly greater diaphragm EMG activity than while performing the IMT at rest in upright or drops postures (p ≤ 0.05). Cycling in drops postures while performing the IMT had a significantly greater diaphragm EMG activity than when performing the IMT at rest in either upright or drops postures (p ≤ 0.05). Sternocleidomastoid muscle activity increased with both cycling and IMT, although posture had little effect. These results support our hypothesis in that the IMT while cycling increases respiratory EMG activity to a significantly greater extent than when performing the IMT solely at rest, suggesting that the combination of IMT and cycling may provide an additive training effect.

  20. Longitudinal Distribution of Solar Magnetic Fields and Activity During the Ending and Starting Periods of Activity Cycles

    NASA Astrophysics Data System (ADS)

    Bumba, V.; Garcia, A.; Klvaňa, M.

    2000-10-01

    Studying the appearance of active regions during periods of solar activity minima, we observed that the magnetic fields of active regions belonging to the old and new cycle were mutually related. This was the reason we decided to investigate the relation of the old and new cycle activity during the two last minima in more detail. We examined the distribution of both activities in heliographic longitude, because the patterns of such distribution change substantially during the time of the minimum, and we studied their relation to the distribution and development of the global (background) magnetic field. We observed that the active regions of the old and new cycles tended to concentrate in the same active longitudes. The sources of their magnetic fluxes seem to have the same heliographic longitude. The beginning of the new cycle activity, occurring at the very beginning to a very weak degree in the equatorial zone, and then proceeding to higher latitudes, occurs in the magnetic field remnants of the old cycle activity. During the transition phase, a relatively large number of small active regions is produced by both cycles.

  1. CpG methylation suppresses transcriptional activity of human syncytin-1 in non-placental tissues

    SciTech Connect

    Matouskova, Magda; Blazkova, Jana; Pajer, Petr; Pavlicek, Adam; Hejnar, Jiri . E-mail: hejnar@img.cas.cz

    2006-04-15

    Syncytin-1 is a captive envelope glycoprotein encoded by one of human endogenous retroviruses W. It is expressed exclusively in the placental trophoblast where it participates in cell-to-cell fusion during differentiation of syncytiotrophobast. In other tissues, however, syncytin-1 expression must be kept in check because inadvertent cell fusion might be dangerous for tissue organization and integrity. We describe here an inverse correlation between CpG methylation of syncytin-1 5' long terminal repeat and its expression. Hypomethylation of the syncytin-1 5' long terminal repeat in the placenta and in the choriocarcinoma-derived cell line BeWo was detected. However, other analyzed primary cells and cell lines non-expressing syncytin-1 contain proviruses heavily methylated in this sequence. CpG methylation of syncytin-1 is resistant to the effect of the demethylating agent 5-azacytidine. The inhibitory role of CpG methylation is further confirmed by transient transfection of in-vitro-methylated syncytin-1 promoter-driven reporter construct. Altogether, we conclude that CpG methylation plays a principal role in the transcriptional suppression of syncytin-1 in non-placental tissues, and, in contrast, demethylation of the syncytin-1 promoter in trophoblast is a prerequisite for its expression and differentiation of multinucleated syncytiotrophoblast.

  2. Serum oxytocinase activity is related to tumor growth parameters in N-methyl nitrosourea induced rat breast cancer.

    PubMed

    Carrera, M P; Ramírez-Expósito, M J; Valenzuela, M T; García, M J; Mayas, M D; Martínez-Martos, J M

    2004-07-30

    Oxytocinase has been reported to hydrolyse the peptide hormone oxytocin (OT). We have previously described changes in oxytocinase activity in human breast cancer, where a highly significant increase occurred in tumoral tissue. In the present work, we analysed oxytocinase activity in serum of rats with breast cancer induced by N-methyl-nitrosourea (NMU). We also correlated these data with the number and size of tumors and the body weight of the animals to evaluate the putative value of this activity as a biological marker of the disease. Our results confirm the involvement of OT in carcinogenesis and suggest a mayor role for oxytocinase activity in the development of breast cancer.

  3. Estrogenic and progestational activity of 7alpha-methyl-19-nortestosterone, a synthetic androgen.

    PubMed

    Beri, R; Kumar, N; Savage, T; Benalcazar, L; Sundaram, K

    1998-11-01

    Synthetic androgens exhibit estrogenic/antiestrogenic and progestational activities in addition to their androgenic effects. To investigate the pharmacological action of the synthetic androgen, 7alpha-methyl-19-nortestosterone (MENT), we examined its action in female rodents. The criteria employed for estrogenic/antiestrogenic effects were, uterine weight increase, vaginal cornification, induction of progesterone receptors (PR) synthesis and stimulation of peroxidase activity in the uteri of ovariectomized rats and mice. MENT increased uterine weight in a dose dependent manner, but did not cause vaginal cornification or stimulate PR synthesis in the uterus. The uterotropic activity of MENT was 200-fold lower than that of estradiol. Estrogen receptor (ER) bound [3H]-E2 was displaced by E2 and MENT with ED50 values of 70 pg and 250 ng, respectively, a 3,500 fold difference in their binding affinity. The low binding of MENT to ER, in contrast to its relatively high uterotropic action, suggested that receptors other than ER may be involved in its action on the uterus. The progestational activity of MENT in immature rabbits using the McPhail index assay was comparable to that of progesterone. Binding affinities of MENT and progesterone to PR were also comparable. However, the action of MENT on the uterus does not seem to be a progestational effect since mifepristone, an antiprogestin, had no effect on MENT-induced uterine growth. Specific androgen receptors (AR) in uterine cytosol were demonstrated. The involvement of AR in MENT action was confirmed by using an antiandrogen (flutamide) and an antiestrogen (ICI-182) in ovariectomized mice. Although MENT did not block the uterotropic effect of E2, it inhibited the E2-induced cornification of vaginal epithelium, induction of uterine PR synthesis and increase in uterine peroxidase activity in ovariectomized rats. The antiestrogenic effect of MENT was also blocked by flutamide. These results suggest that the uterotropic and

  4. Physical activity of adult female rhesus monkeys (Macaca mulatta) across the menstrual cycle.

    PubMed

    Hunnell, Nathan A; Rockcastle, Nathan J; McCormick, Kristen N; Sinko, Laurel K; Sullivan, Elinor L; Cameron, Judy L

    2007-06-01

    Physical activity is an important physiological variable impacting on a number of systems in the body. In rodents and several species of domestic animals, levels of physical activity have been reported to vary across the estrous cycle; however, it is unclear whether such changes in activity occur in women and other primates across the menstrual cycle. To determine whether significant changes in activity occur over the menstrual cycle, we continuously measured physical activity in seven adult female rhesus monkeys by accelerometry over the course of one menstrual cycle. Monkeys were checked daily for menses, and daily blood samples were collected for measurement of reproductive hormones. All monkeys displayed ovulatory menstrual cycles, ranging from 23 to 31 days in length. There was a significant increase in estradiol from the early follicular phase to the day of ovulation (F(1.005,5.023) = 40.060, P = 0.001). However, there was no significant change in physical activity across the menstrual cycle (F(2,12) = 0.225, P = 0.802), with activity levels being similar in the early follicular phase, on the day of the preovulatory rise in estradiol and during the midluteal phase. Moreover, the physical activity of these monkeys was not outside the range of physical activity that we measured in 15 ovariectomized monkeys. We conclude that, in primates, physical activity does not change across the menstrual cycle and is not influenced by physiological changes in circulating estradiol. This finding will allow investigators to record physical activity in female primates without the concern of controlling for the phase of the menstrual cycle.

  5. Characterization and Antimicrobial Activity of N-Methyl-2-pyrrolidone-loaded Ethylene Oxide-Propylene Oxide Block Copolymer Thermosensitive Gel

    PubMed Central

    Phaechamud, T.; Mahadlek, J.; Charoenteeraboon, J.; Choopun, S.

    2012-01-01

    The purpose of this study is to investigate the effects of N-methyl-2-pyrrolidone on the thermosensitive properties of aqueous ethylene oxide-propylene oxide block copolymer (Lutrol® F127) system. Due to the aqueous solubility enhancement and biocompatibility, N-methyl-2-pyrrolidone is an interesting solubilizer for the poorly water soluble drugs to be incorporated in the Lutrol® F127 system. Effect of N-methyl-2-pyrrolidone on physicochemical properties of Lutrol® F127 system was investigated using appearance, pH, gelation, gel melting temperature and rheology. The antimicrobial activity of the thermosensitive N-methyl-2-pyrrolidone gel was also tested. Lower N-methyl-2-pyrrolidone amount (≤30%w/w) could shift the sol-gel transition to a lower temperature but the gel-sol transition was shifted to a higher temperature. Higher N-methyl-2-pyrrolidone (≥40%w/w) could shift both sol-gel and gel-sol transitions of the system to a lower temperature. The amount of N-methyl-2-pyrrolidone >60% w/w could reverse the phase of the Lutrol® F127 system to non-newtonian flow at 4° and Newtonian flow at high temperature. Aqueous Lutrol® F127 system containing N-methyl-2-pyrrolidone exhibited antimicrobial activities against Staphylococcus aureus, Escherichia coli and Candida albicans with the N-methyl-2-pyrrolidone in a dose-dependent manner. PMID:23798774

  6. Cycling for Students with ASD: Self-Regulation Promotes Sustained Physical Activity

    ERIC Educational Resources Information Center

    Todd, Teri; Reid, Greg; Butler-Kisber, Lynn

    2010-01-01

    Individuals with autism often lack motivation to engage in sustained physical activity. Three adolescents with severe autism participated in a 16-week program and each regularly completed 30 min of cycling at the end of program. This study investigated the effect of a self-regulation instructional strategy on sustained cycling, which included…

  7. How Y357F, Y276F mutants affect the methylation activity of PRDM9: QM/MM MD and free energy simulations.

    PubMed

    Chu, Yuzhuo; Sun, Lu; Zhong, Shijun

    2015-05-01

    Histone methyltransferase PRDM9 catalyzes the methylation of H3K4me2 (histone 3 dimethylated lysine 4) to H3K4me3 (histone 3 trimethylated lysine 4) by transferring the methyl group from S-adenosyl methionine (AdoMet). PRDM9 is the major determinant of the meiotic recombination hotspot and the enrichment of H3K4me3 at the hotspot defines the initiation site of meiotic recombination. In PRDM9, two conserved tyrosine residues Tyr357 and Tyr276 surrounding the amino group of the substrate lysine may influence the methylation activity through hydrogen bond interactions with AdoMet or the substrate lysine. In this study, quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) and free energy simulations were performed to reveal the methylation processes catalyzed by wild type PRDM9, its Y357F, and Y276F mutants, respectively. The different roles of Tyr357 and Tyr276 in the methylation activity of PRDM9 were also investigated and compared. The calculated free energy barriers of the methyl transfers suggest that the Y276F mutation decreases the catalytic activity of the methyl transfer, while the Y357F mutation does not change the catalytic activity of the methyl transfer. The reactant complex conformations generated in the QM/MM MD simulations show that the reactive configuration can be formed in the Y357F mutant but not in the Y276F mutant.

  8. Prenatal Polycyclic Aromatic Hydrocarbon, Adiposity, Peroxisome Proliferator-Activated Receptor (PPAR) γ Methylation in Offspring, Grand-Offspring Mice

    PubMed Central

    Yan, Zhonghai; Zhang, Hanjie; Maher, Christina; Arteaga-Solis, Emilio; Champagne, Frances A.; Wu, Licheng; McDonald, Jacob D.; Yan, Beizhan; Schwartz, Gary J.; Miller, Rachel L.

    2014-01-01

    Rationale Greater levels of prenatal exposure to polycyclic aromatic hydrocarbon (PAH) have been associated with childhood obesity in epidemiological studies. However, the underlying mechanisms are unclear. Objectives We hypothesized that prenatal PAH over-exposure during gestation would lead to weight gain and increased fat mass in offspring and grand-offspring mice. Further, we hypothesized that altered adipose gene expression and DNA methylation in genes important to adipocyte differentiation would be affected. Materials and Methods Pregnant dams were exposed to a nebulized PAH mixture versus negative control aerosol 5 days a week, for 3 weeks. Body weight was recorded from postnatal day (PND) 21 through PND60. Body composition, adipose cell size, gene expression of peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer-binding proteins (C/EBP) α, cyclooxygenase (Cox)-2, fatty acid synthase (FAS) and adiponectin, and DNA methylation of PPAR γ, were assayed in both the offspring and grand-offspring adipose tissue. Findings Offspring of dams exposed to greater PAH during gestation had increased weight, fat mass, as well as higher gene expression of PPAR γ, C/EBP α, Cox2, FAS and adiponectin and lower DNA methylation of PPAR γ. Similar differences in phenotype and DNA methylation extended through the grand-offspring mice. Conclusions Greater prenatal PAH exposure was associated with increased weight, fat mass, adipose gene expression and epigenetic changes in progeny. PMID:25347678

  9. Highly Active Gold(I)-Silver(I) Oxo Cluster Activating sp³ C-H Bonds of Methyl Ketones under Mild Conditions.

    PubMed

    Pei, Xiao-Li; Yang, Yang; Lei, Zhen; Chang, Shan-Shan; Guan, Zong-Jie; Wan, Xian-Kai; Wen, Ting-Bin; Wang, Quan-Ming

    2015-04-29

    The activation of C(sp(3))-H bonds is challenging, due to their high bond dissociation energy, low proton acidity, and highly nonpolar character. Herein we report a unique gold(I)-silver(I) oxo cluster protected by hemilabile phosphine ligands [OAu3Ag3(PPhpy2)3](BF4)4 (1), which can activate C(sp(3))-H bonds under mild conditions for a broad scope of methyl ketones (RCOCH3, R = methyl, phenyl, 2-methylphenyl, 2-aminophenyl, 2-hydroxylphenyl, 2-pyridyl, 2-thiazolyl, tert-butyl, ethyl, isopropyl). Activation happens via triple deprotonation of the methyl group, leading to formation of heterometallic Au(I)-Ag(I) clusters with formula RCOCAu4Ag4(PPhpy2)4(BF4)5 (PPhpy2 = bis(2-pyridyl)phenylphosphine). Cluster 1 can be generated in situ via the reaction of [OAu3Ag(PPhpy2)3](BF4)2 with 2 equiv of AgBF4. The oxo ion and the metal centers are found to be essential in the cleavage of sp(3) C-H bonds of methyl ketones. Interestingly, cluster 1 selectively activates the C-H bonds in -CH3 rather than the N-H bonds in -NH2 or the O-H bond in -OH which is traditionally thought to be more reactive than C-H bonds. Control experiments with butanone, 3-methylbutanone, and cyclopentanone as substrates show that the auration of the C-H bond of the terminal methyl group is preferred over secondary or tertiary sp(3) C-H bonds; in other words, the C-H bond activation is influenced by steric effect. This work highlights the powerful reactivity of metal clusters toward C-H activation and sheds new light on gold(I)-mediated catalysis.

  10. Nitrogen storage and remobilization in Brassica napus L. during the growth cycle: effects of methyl jasmonate on nitrate uptake, senescence, growth, and VSP accumulation.

    PubMed

    Rossato, L; MacDuff, J H; Laine, P; Le Deunff, E; Ourry, A

    2002-05-01

    The role of methyl jasmonate (MeJa) in promoting senescence has been described previously in many species, but it has been questioned in monocarpic species whether induced senescence is a result of a potential death hormone like MeJa, or a consequence of an increased metabolic drain resulting from the growth of reproductive tissue. In oilseed rape (Brassica napus L.), a polypeptide of 23 kDa has been recently identified as a putative vegetative storage protein (VSP). This polypeptide could be used as a storage buffer between N losses from senescing leaves putatively promoted by methyl jasmonate that might be produced by flowers, and grain filling which occurs later on, while N uptake is strongly reduced. In order to describe causal relationships during Brassica napus L. plant responses to MeJa treatment, a kinetic experiment was performed to determine the order and the amplitude with which general processes such as growth, photosynthesis, chlorophyll content, N uptake, and N storage under the form of the 23 kDa VSP are affected. One of the most immediate consequences of MeJa treatment was the strong reduction of nitrate uptake within 6 h, relative to control plants. However, this was not a specific effect as K(+) uptake was similarly affected. Photosynthesis was reduced later (after 24 h), while chlorophyll content as well as leaf growth also decreased in a similar way. Moreover, this was concomitant with a remobilization of endogenous unlabelled N from senescing leaves to roots. Accumulation of the 23 kDa VSP was induced in the taproot after 24 h of MeJa treatment and was increased 10-fold within 8 d. On the other hand, the reversible effect of a MeJa pretreatment was tested in the long term (i.e. along the growth cycle) using plants previously grown in field conditions induced for flowering. Results show that a MeJa pulse induced a reversible effect on N uptake inhibition. In parallel, protein immunologically related to the 23 kDa VSP was detected in stems with a

  11. Dynamic Changes in the Follicular Transcriptome and Promoter DNA Methylation Pattern of Steroidogenic Genes in Chicken Follicles throughout the Ovulation Cycle

    PubMed Central

    Zhu, Guiyu; Mao, Yong; Zhou, Wendi; Jiang, Yunliang

    2015-01-01

    The molecular mechanisms associated with follicle maturation and ovulation are not well defined in avian species. In this study, we used RNA-seq to study the gene expression profiles of the chicken follicles from different developmental stages (pre-hierarchical, pre-ovulatory and post-ovulatory). Transcriptomic analysis revealed a total of 1,277 and 2,310 genes were differentially expressed when follicles progressed through the pre-hierarchical to hierarchical and pre-ovulatory to post-ovulatory transitions, respectively. The differentially expressed genes (DEG) were involved in signaling pathways such as adherens junction, apoptosis and steroid biosynthesis. We further investigated the transcriptional regulation of follicular steroidogenesis by examining the follicle-specific methylation profiles of Star (steroidogenic acute regulatory protein), Cyp11a1 (cytochrome P450, family 11, subfamily a, polypeptide 1) and Hsd3b (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1), genes encoding the key enzymes for progesterone synthesis. The varied patterns of DNA methylation in proximal promoters of Star and Cyp11a1but not Hsd3b in different follicles could play a major role in controlling gene expression as well as follicular steroidogenic activity. Finally, the promoter-reporter analysis suggests that TGF-β could be involved in the regulation of Hsd3b expression during ovulation. Together, current data not only provide novel insights into the molecular mechanisms of follicular physiology in chicken follicles, but also present the first evidence of epigenetic regulation of ovarian steroidogenesis in avian species. PMID:26716441

  12. Easy activation of two C-H bonds of an N-heterocyclic carbene N-methyl group.

    PubMed

    Cabeza, Javier A; del Río, Ignacio; Miguel, Daniel; Sánchez-Vega, M Gabriela

    2005-08-21

    The first trinuclear clusters containing NHC ligands are described; the compound [Ru3(Me2Im)(CO)11](Me2Im=1,3-dimethylimidazol-2-ylidene) is easily converted into [Ru3(mu-H)2(mu3-MeImCH)(CO)9] by a process involving the activation of two C-H bonds of a methyl group that is an example of degradation of a metal-coordinated NHC ligand under mild conditions.

  13. Cell cycle-coupled expansion of AR activity promotes cancer progression.

    PubMed

    McNair, C; Urbanucci, A; Comstock, C E S; Augello, M A; Goodwin, J F; Launchbury, R; Zhao, S G; Schiewer, M J; Ertel, A; Karnes, J; Davicioni, E; Wang, L; Wang, Q; Mills, I G; Feng, F Y; Li, W; Carroll, J S; Knudsen, K E

    2017-03-23

    The androgen receptor (AR) is required for prostate cancer (PCa) survival and progression, and ablation of AR activity is the first line of therapeutic intervention for disseminated disease. While initially effective, recurrent tumors ultimately arise for which there is no durable cure. Despite the dependence of PCa on AR activity throughout the course of disease, delineation of the AR-dependent transcriptional network that governs disease progression remains elusive, and the function of AR in mitotically active cells is not well understood. Analyzing AR activity as a function of cell cycle revealed an unexpected and highly expanded repertoire of AR-regulated gene networks in actively cycling cells. New AR functions segregated into two major clusters: those that are specific to cycling cells and retained throughout the mitotic cell cycle ('Cell Cycle Common'), versus those that were specifically enriched in a subset of cell cycle phases ('Phase Restricted'). Further analyses identified previously unrecognized AR functions in major pathways associated with clinical PCa progression. Illustrating the impact of these unmasked AR-driven pathways, dihydroceramide desaturase 1 was identified as an AR-regulated gene in mitotically active cells that promoted pro-metastatic phenotypes, and in advanced PCa proved to be highly associated with development of metastases, recurrence after therapeutic intervention and reduced overall survival. Taken together, these findings delineate AR function in mitotically active tumor cells, thus providing critical insight into the molecular basis by which AR promotes development of lethal PCa and nominate new avenues for therapeutic intervention.

  14. Anaerobic Activation of p-Cymene in Denitrifying Betaproteobacteria: Methyl Group Hydroxylation versus Addition to Fumarate

    PubMed Central

    Strijkstra, Annemieke; Trautwein, Kathleen; Jarling, René; Wöhlbrand, Lars; Dörries, Marvin; Reinhardt, Richard; Drozdowska, Marta; Golding, Bernard T.; Wilkes, Heinz

    2014-01-01

    The betaproteobacteria “Aromatoleum aromaticum” pCyN1 and “Thauera” sp. strain pCyN2 anaerobically degrade the plant-derived aromatic hydrocarbon p-cymene (4-isopropyltoluene) under nitrate-reducing conditions. Metabolite analysis of p-cymene-adapted “A. aromaticum” pCyN1 cells demonstrated the specific formation of 4-isopropylbenzyl alcohol and 4-isopropylbenzaldehyde, whereas with “Thauera” sp. pCyN2, exclusively 4-isopropylbenzylsuccinate and tentatively identified (4-isopropylphenyl)itaconate were observed. 4-Isopropylbenzoate in contrast was detected with both strains. Proteogenomic investigation of p-cymene- versus succinate-adapted cells of the two strains revealed distinct protein profiles agreeing with the different metabolites formed from p-cymene. “A. aromaticum” pCyN1 specifically produced (i) a putative p-cymene dehydrogenase (CmdABC) expected to hydroxylate the benzylic methyl group of p-cymene, (ii) two dehydrogenases putatively oxidizing 4-isopropylbenzyl alcohol (Iod) and 4-isopropylbenzaldehyde (Iad), and (iii) the putative 4-isopropylbenzoate-coenzyme A (CoA) ligase (Ibl). The p-cymene-specific protein profile of “Thauera” sp. pCyN2, on the other hand, encompassed proteins homologous to subunits of toluene-activating benzylsuccinate synthase (termed [4-isopropylbenzyl]succinate synthase IbsABCDEF; identified subunits, IbsAE) and protein homologs of the benzylsuccinate β-oxidation (Bbs) pathway (termed BisABCDEFGH; all identified except for BisEF). This study reveals that two related denitrifying bacteria employ fundamentally different peripheral degradation routes for one and the same substrate, p-cymene, with the two pathways apparently converging at the level of 4-isopropylbenzoyl-CoA. PMID:25261521

  15. Activity of the lactate-alanine shuttle is independent of glutamate-glutamine cycle activity in cerebellar neuronal-astrocytic cultures.

    PubMed

    Bak, Lasse K; Sickmann, Helle M; Schousboe, Arne; Waagepetersen, Helle S

    The glutamate-glutamine cycle describes the neuronal release of glutamate into the synaptic cleft, astrocytic uptake, and conversion into glutamine, followed by release for use as a neuronal glutamate precursor. This only explains the fate of the carbon atoms, however, and not that of the ammonia. Recently, a role for alanine has been proposed in transfer of ammonia between glutamatergic neurons and astrocytes, denoted the lactate-alanine shuttle (Waagepetersen et al. [ 2000] J. Neurochem. 75:471-479). The role of alanine in this context has been studied further using cerebellar neuronal cultures and corresponding neuronal-astrocytic cocultures. A superfusion paradigm was used to induce repetitively vesicular glutamate release by N-methyl-D-aspartate (NMDA) in the neurons, allowing the relative activity dependency of the lactate-alanine shuttle to be assessed. [(15)N]Alanine (0.2 mM), [2-(15)N]/[5-(15)N]glutamine (0.25 mM), and [(15)N]ammonia (0.3 mM) were used as precursors and cell extracts were analyzed by mass spectrometry. Labeling from [(15)N]alanine in glutamine, aspartate, and glutamate in cerebellar cocultures was independent of depolarization of the neurons. Employing glutamine with the amino group labeled ([2-(15)N]glutamine) as the precursor, an activity-dependent increase in the labeling of both glutamate and aspartate (but not alanine) was observed in the cerebellar neurons. When the amide group of glutamine was labeled ([5-(15)N]glutamine), no labeling could be detected in the analyzed metabolites. Altogether, the results of this study support the existence of the lactate-alanine shuttle and the associated glutamate-glutamine cycle. No direct coupling of the two shuttles was observed, however, and only the glutamate-glutamine cycle seemed activity dependent.

  16. Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture

    PubMed Central

    Ross, Heather A.; Wright, Kathryn M.; McDougall, Gordon J.; Roberts, Alison G.; Chapman, Sean N.; Morris, Wayne L.; Hancock, Robert D.; Stewart, Derek; Tucker, Gregory A.; James, Euan K.; Taylor, Mark A.

    2011-01-01

    Although cooked potato tuber texture is an important trait that influences consumer preference, a detailed understanding of tuber textural properties at the molecular level is lacking. Previous work has identified tuber pectin methyl esterase activity (PME) as a potential factor impacting on textural properties. In this study, tuber PME isoform and gene expression profiles have been determined in potato germplasm with differing textural properties as assessed using an amended wedge fracture method and a sloughing assay, revealing major differences between the potato types. Differences in pectin structure between potato types with different textural properties were revealed using monoclonal antibodies specific for different pectic epitopes. Chemical analysis of tuber pectin clearly demonstrated that, in tubers containing a higher level of total PME activity, there was a reduced degree of methylation of cell wall pectin and consistently higher peak force and work done values during the fracture of cooked tuber samples, demonstrating the link between PME activity, the degree of methylation of cell wall pectin, and cooked tuber textural properties. PMID:20855456

  17. Potato tuber pectin structure is influenced by pectin methyl esterase activity and impacts on cooked potato texture.

    PubMed

    Ross, Heather A; Wright, Kathryn M; McDougall, Gordon J; Roberts, Alison G; Chapman, Sean N; Morris, Wayne L; Hancock, Robert D; Stewart, Derek; Tucker, Gregory A; James, Euan K; Taylor, Mark A

    2011-01-01

    Although cooked potato tuber texture is an important trait that influences consumer preference, a detailed understanding of tuber textural properties at the molecular level is lacking. Previous work has identified tuber pectin methyl esterase activity (PME) as a potential factor impacting on textural properties. In this study, tuber PME isoform and gene expression profiles have been determined in potato germplasm with differing textural properties as assessed using an amended wedge fracture method and a sloughing assay, revealing major differences between the potato types. Differences in pectin structure between potato types with different textural properties were revealed using monoclonal antibodies specific for different pectic epitopes. Chemical analysis of tuber pectin clearly demonstrated that, in tubers containing a higher level of total PME activity, there was a reduced degree of methylation of cell wall pectin and consistently higher peak force and work done values during the fracture of cooked tuber samples, demonstrating the link between PME activity, the degree of methylation of cell wall pectin, and cooked tuber textural properties.

  18. Heavy-ion radiation induces both activation of multiple endogenous transposable elements and alterations in DNA methylation in rice

    NASA Astrophysics Data System (ADS)

    Zhang, Meng; Sun, Yeqing; Li, Xishan; Xiaolin, Cui; Li, Xiang

    2012-07-01

    Space radiation represents a complex environmental condition in which several interacting factors such as electron, neutron, proton, heavy-ion are involved, which may provoke stress responses and jeopardize genome integrity. Given the inherent property of epigenetic modifications to respond to intrinsic aswell as external perturbations, it is conceivable that epigenetic markers like DNA methylation and transposition may undergo alterations in response to space radiation. Cytosine DNA methylation plays important roles in maintaining genome stability and controlling gene expression. A predominant means for Transposable elements (TEs) to cause genetic instability is via their transpositional activation. To find the detailed molecular characterization of the nature of genomic changes induced by space radiation, the seeds of rice were exposed to 0.02, 0.2, 1, 2 and 20 Gy dose of ^{12}C heavy-ion radiation, respectively. We found that extensive alteration in both DNA methylation and gene expression occurred in rice plants after different dose of heavy-ion radiation. Here we shown that heavy-ion radiation has induced transposition of mPing and Tos17 in rice, which belong to distinct classes including the miniature inverted terminal repeat TEs (MITEs) and long-terminal repeat (LTR) retrotransposons, respectively. mPing and Tos17 mobility were found to correlate with cytosine methylation alteration detected by MSAP and genetic variation detected by AFLP. The result showed that at least in some cases transposition of TEs was associated with cytosine demethylation within the elements. Our results implicate that the heavy-ion radiation represents a potent mutagenic agent that can cause genomic instabilities by eliciting transposition of endogenous TEs in rice. Keywords: Heavy-ion radiation, DNA methylation, Transposable elements, mPing, Tos17

  19. Multiple resistance to pirimiphos-methyl and bifenthrin in Tribolium castaneum involves the activity of lipases, esterases, and laccase2.

    PubMed

    Julio, Alison Henrique Ferreira; Gigliolli, Adriana Aparecida Sinópolis; Cardoso, Kátia Aparecida Kern; Drosdoski, Sandro Daniel; Kulza, Rodrigo Amaral; Seixas, Flávio Augusto Vicente; Ruvolo-Takasusuki, Maria Claudia Colla; de Souza, Cristina Giatti Marques; Lapenta, Ana Silvia

    2017-05-01

    Several recent studies have elucidated the molecular mechanisms that confer insecticide resistance on insect pests. However, little is known about multiple resistance in red flour beetle (Tribolium castaneum) at molecular level. The multiple resistance is characterized as resistance to different classes of insecticides that have different target sites, and is mediated by several enzymatic systems. In this study, we investigated the biochemical and molecular mechanisms involved in multiple resistance of T. castaneum to bifenthrin (pyrethroid [Pyr]) and pirimiphos-methyl (organophosphate [Org]). We used artificial selection, biochemical and in silico approaches including structural computational biology. After five generations of artificial selection in the presence of bifenthrin (F5Pyr) or pirimiphos-methyl (F5Org), we found high levels of multiple resistance. The hierarchical enzymatic cluster revealed a pool of esterases (E), lipases (LIPs) and laccase2 (LAC2) potentially contributing to the resistance in different ways throughout development, after one or more generations in the presence of insecticides. The enzyme-insecticide interaction network indicated that E2, E3, LIP3, and LAC2 are enzymes potentially required for multiple resistance phenotype. Kinetic analysis of esterases from F5Pyr and F5Org showed that pirimiphos-methyl and specially bifenthrin promote enzyme inhibition, indicating that esterases mediate resistance by sequestering bifenthrin and pirimiphos-methyl. Our computational data were in accordance with kinetic results, indicating that bifenthrin has higher affinity at the active site of esterase than pirimiphos-methyl. We also report the capability of these insecticides to modify the development in T. castaneum. Our study provide insights into the biochemical mechanisms employed by T. castaneum to acquire multiple resistance.

  20. BrainCycles: Experimental Setup for the Combined Measurement of Cortical and Subcortical Activity in Parkinson's Disease Patients during Cycling

    PubMed Central

    Gratkowski, Maciej; Storzer, Lena; Butz, Markus; Schnitzler, Alfons; Saupe, Dietmar; Dalal, Sarang S.

    2017-01-01

    Recently, it has been demonstrated that bicycling ability remains surprisingly preserved in Parkinson's disease (PD) patients who suffer from freezing of gait. Cycling has been also proposed as a therapeutic means of treating PD symptoms, with some preliminary success. The neural mechanisms behind these phenomena are however not yet understood. One of the reasons is that the investigations of neuronal activity during pedaling have been up to now limited to PET and fMRI studies, which restrict the temporal resolution of analysis, and to scalp EEG focused on cortical activation. However, deeper brain structures like the basal ganglia are also associated with control of voluntary motor movements like cycling and are affected by PD. Deep brain stimulation (DBS) electrodes implanted for therapy in PD patients provide rare and unique access to directly record basal ganglia activity with a very high temporal resolution. In this paper we present an experimental setup allowing combined investigation of basal ganglia local field potentials (LFPs) and scalp EEG underlying bicycling in PD patients. The main part of the setup is a bike simulator consisting of a classic Dutch-style bicycle frame mounted on a commercially available ergometer. The pedal resistance is controllable in real-time by custom software and the pedal position is continuously tracked by custom Arduino-based electronics using optical and magnetic sensors. A portable bioamplifier records the pedal position signal, the angle of the knee, and the foot pressure together with EEG, EMG, and basal ganglia LFPs. A handlebar-mounted display provides additional information for patients riding the bike simulator, including the current and target pedaling rate. In order to demonstrate the utility of the setup, example data from pilot recordings are shown. The presented experimental setup provides means to directly record basal ganglia activity not only during cycling but also during other movement tasks in patients who

  1. Activity of the northern and southern hemispheres as a basis of the solar cycle manifestation

    NASA Astrophysics Data System (ADS)

    Ryabov, M. I.

    2015-12-01

    The dynamics of the evolution of solar cycles is considered a result of the activity manifestation in the northern and southern hemispheres. A study was performed based on separate datasets for the northern and southern hemispheres that contain the monthly and daily averages of the areas of sunspot groups for the period covering activity cycles from 12 to 24 (1874-2013) and the daily values of the Wolf number in the northern and southern hemispheres during cycles 23-24 (1992-2013).To obtain a pattern of development of the "northern" and "southern" solar cycles in detail, a special technique for the extended application of the wavelet analysis has been developed. It allows different the wave processes forming a solar cycle to be distinguished, together with the time of their existence. The application of bandpass Fourier filtering to the obtained data shows that the length of "11-year" cycles by the index S p varies from 10.2 to 11.5 years in the northern hemisphere and from 9.7 to 13.2 years in the southern. The 19th "northern" and 18th "southern" cycles turned out to be maximal. The formation of each of the cycles by all activity indices is determined by the joint effect of long-period processes lasting from 3 to 7 years and short-period processes lasting less than 2 years. When moving from one cycle to another, the long-period processes demonstrate mergings, separations, modulation, and periodic decays. The abnormal activity that appears during the growth, maximum, or decay phase of a cycle is formed at the expense of the simultaneous strengthening of short-period processes, the lengths and "period spectra" of which noticeably differ in the northern and southern hemispheres.

  2. DNA methylation profiling identifies CG methylation clusters in Arabidopsis genes.

    PubMed

    Tran, Robert K; Henikoff, Jorja G; Zilberman, Daniel; Ditt, Renata F; Jacobsen, Steven E; Henikoff, Steven

    2005-01-26

    Cytosine DNA methylation in vertebrates is widespread, but methylation in plants is found almost exclusively at transposable elements and repetitive DNA. Within regions of methylation, methylcytosines are typically found in CG, CNG, and asymmetric contexts. CG sites are maintained by a plant homolog of mammalian Dnmt1 acting on hemi-methylated DNA after replication. Methylation of CNG and asymmetric sites appears to be maintained at each cell cycle by other mechanisms. We report a new type of DNA methylation in Arabidopsis, dense CG methylation clusters found at scattered sites throughout the genome. These clusters lack non-CG methylation and are preferentially found in genes, although they are relatively deficient toward the 5' end. CG methylation clusters are present in lines derived from different accessions and in mutants that eliminate de novo methylation, indicating that CG methylation clusters are stably maintained at specific sites. Because 5-methylcytosine is mutagenic, the appearance of CG methylation clusters over evolutionary time predicts a genome-wide deficiency of CG dinucleotides and an excess of C(A/T)G trinucleotides within transcribed regions. This is exactly what we find, implying that CG methylation clusters have contributed profoundly to plant gene evolution. We suggest that CG methylation clusters silence cryptic promoters that arise sporadically within transcription units.

  3. Characterization of Albendazole-Randomly Methylated-β-Cyclodextrin Inclusion Complex and In Vivo Evaluation of Its Antihelmitic Activity in a Murine Model of Trichinellosis

    PubMed Central

    García, Agustina; Leonardi, Darío; Vasconi, María D.; Hinrichsen, Lucila I.; Lamas, María C.

    2014-01-01

    Albendazole is a benzimidazole carbamate extensively used in oral chemotherapy against intestinal parasites, due to its broad spectrum activity, good tolerance and low cost. However, the drug has the disadvantage of poor bioavailability due to its very low solubility in water; as a consequence, a very active area of research focuses on the development of new pharmaceutical formulations to increase its solubility, dissolution rate, and bioavailability. The primary objective of this study was to prepare randomly methylated β-cyclodextrins inclusion complexes to increase albendazole dissolution rate, in order to enhance its antiparasitic activity. This formulation therapeutic efficacy was contrasted with that of the pure drug by treating Trichinella spiralis infected mice during the intestinal phase of the parasite cycle, on days five and six post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral stage on day 30 post-infection, when compared with the untreated control. Thus, it could be demonstrated that the inclusion complexes improve the in vivo therapeutic activity of albendazole. PMID:25406084

  4. Circadian fluctuations in circulating plasminogen activator inhibitor-1 are independent of feeding cycles in mice.

    PubMed

    Oishi, Katsutaka; Ohkura, Naoki; Yasumoto, Yuki; Yamamoto, Saori

    2017-01-01

    To evaluate the involvement of the day-night feeding cycle in the circadian regulation of circulating plasminogen activator inhibitor-1 (PAI-1) concentrations, mice were fed with a diet for eight hours during either daytime (DF) or nighttime (NF) for one week. The reversed feeding cycle did not affect the circadian phases of plasma PAI-1 levels as well as the nocturnal wheel-running activity, although the phase of Pai-1 mRNA expression was significantly advanced for 8.6 hours in the livers of DF, compared with NF mice. The day-night feeding cycle is not a critical Zeitgeber for circadian rhythm of circulating PAI-1.

  5. Viral activities and life cycles in deep subseafloor sediments.

    PubMed

    Engelhardt, Tim; Orsi, William D; Jørgensen, Bo Barker

    2015-12-01

    Viruses are highly abundant in marine subsurface sediments and can even exceed the number of prokaryotes. However, their activity and quantitative impact on microbial populations are still poorly understood. Here, we use gene expression data from published continental margin subseafloor metatranscriptomes to qualitatively assess viral diversity and activity in sediments up to 159 metres below seafloor (mbsf). Mining of the metatranscriptomic data revealed 4651 representative viral homologues (RVHs), representing 2.2% of all metatranscriptome sequence reads, which have close translated homology (average 77%, range 60-97% amino acid identity) to viral proteins. Archaea-infecting RVHs are exclusively detected in the upper 30 mbsf, whereas RVHs for filamentous inoviruses predominate in the deepest sediment layers. RVHs indicative of lysogenic phage-host interactions and lytic activity, notably cell lysis, are detected at all analysed depths and suggest a dynamic virus-host association in the marine deep biosphere studied here. Ongoing lytic viral activity is further indicated by the expression of clustered, regularly interspaced, short palindromic repeat-associated cascade genes involved in cellular defence against viral attacks. The data indicate the activity of viruses in subsurface sediment of the Peruvian margin and suggest that viruses indeed cause cell mortality and may play an important role in the turnover of subseafloor microbial biomass.

  6. Contextualizing Solar Cycle 24: Report on the Development of a Homogenous Database of Bipolar Active Regions Spanning Four Cycles

    NASA Astrophysics Data System (ADS)

    Munoz-Jaramillo, A.; Werginz, Z. A.; DeLuca, M. D.; Vargas-Acosta, J. P.; Longcope, D. W.; Harvey, J. W.; Martens, P.; Zhang, J.; Vargas-Dominguez, S.; DeForest, C. E.; Lamb, D. A.

    2015-12-01

    The solar cycle can be understood as a process that alternates the large-scale magnetic field of the Sun between poloidal and toroidal configurations. Although the process that transitions the solar cycle between toroidal and poloidal phases is still not fully understood, theoretical studies, and observational evidence, suggest that this process is driven by the emergence and decay of bipolar magnetic regions (BMRs) at the photosphere. Furthermore, the emergence of BMRs at the photosphere is the main driver behind solar variability and solar activity in general; making the study of their properties doubly important for heliospheric physics. However, in spite of their critical role, there is still no unified catalog of BMRs spanning multiple instruments and covering the entire period of systematic measurement of the solar magnetic field (i.e. 1975 to present).In this presentation we discuss an ongoing project to address this deficiency by applying our Bipolar Active Region Detection (BARD) code on full disk magnetograms measured by the 512 (1975-1993) and SPMG (1992-2003) instruments at the Kitt Peak Vacuum Telescope (KPVT), SOHO/MDI (1996-2011) and SDO/HMI (2010-present). First we will discuss the results of our revitalization of 512 and SPMG KPVT data, then we will discuss how our BARD code operates, and finally report the results of our cross-callibration.The corrected and improved KPVT magnetograms will be made available through the National Solar Observatory (NSO) and Virtual Solar Observatory (VSO), including updated synoptic maps produced by running the corrected KPVT magnetograms though the SOLIS pipeline. The homogeneous active region database will be made public by the end of 2017 once it has reached a satisfactory level of quality and maturity. The Figure shows all bipolar active regions present in our database (as of Aug 2015) colored according to the sign of their leading polarity. Marker size is indicative of the total active region flux. Anti

  7. Life Cycle of the Salmon. Ocean Related Curriculum Activities.

    ERIC Educational Resources Information Center

    Tarabochia, Kathy

    The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

  8. Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Jastrow, J. D.

    2004-12-01

    Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

  9. Hand-cycling: an active form of wheeled mobility, recreation, and sports.

    PubMed

    Hettinga, F J; Valent, L; Groen, W; van Drongelen, S; de Groot, S; van der Woude, L H V

    2010-02-01

    By studying exercise and performance in hand-cycling in both activities of daily living and in Paralympic sport settings, new insights can be gained for rehabilitation practice, adapted physical activity, and sports. This review looks into the pros and cons of hand-cycling in both rehabilitation and optimal sports performance settings as suggested from the current-but still limited-scientific literature and experimentation. Despite the limited evidence-base and the diversity of study approaches and methodologies, this study suggests an important role for hand-cycling during and after rehabilitation, and in wheeled mobility recreation and sports. An approach that combines biomechanical, physiological, and psychosocial elements may lead to a better understanding of the benefits of hand-cycling and of the fundamentals of exercise in rehabilitation, activities of daily living, and sports.

  10. Regulation of RNA polymerase II activity by CTD phosphorylation and cell cycle control.

    PubMed

    Oelgeschläger, Thomas

    2002-02-01

    The carboxyl-terminal domain (CTD) of the largest subunit of mammalian RNA polymerase II (RNAP II) consists of 52 repeats of a consensus heptapeptide and is subject to phosphorylation and dephosphorylation events during each round of transcription. RNAP II activity is regulated during the cell cycle and cell cycle-dependend changes in RNAP II activity correlate well with CTD phosphorylation. In addition, global changes in the CTD phosphorylation status are observed in response to mitogenic or cytostatic signals such as growth factors, mitogens and DNA-damaging agents. Several CTD kinases are members of the cyclin-dependent kinase (CDK) superfamily and associate with transcription initiation complexes. Other CTD kinases implicated in cell cycle regulation include the mitogen-activated protein kinases ERK-1/2 and the c-Abl tyrosine kinase. These observations suggest that reversible RNAP II CTD phosphorylation may play a key role in linking cell cycle regulatory events to coordinated changes in transcription.

  11. The Synthesis, Characterization, and Application of 13C-Methyl Isocyanide as an NMR Probe of Heme Protein Active Sites

    PubMed Central

    McCullough, Christopher; Pullela, Phani Kumar; Im, Sang-Choul; Waskell, Lucy; Sem, Daniel

    2014-01-01

    The cytochromes P450 (CYPs) play a central role in a variety of important biological oxidations, such as steroid synthesis and the metabolism of xenobiotic compounds, including most drugs. Because CYPs are frequently assayed as drug targets or as anti-targets, tools that provide confirmation of active-site binding and information on binding orientation would be of great utility. Of greatest value are assays that are reasonably high throughput. Other heme proteins, too—such as the nitric oxide synthases (NOSs), with their importance in signaling, regulation of blood pressure, and involvement in the immune response—often display critical roles in the complex functions of many higher organisms, and also require improved assay methods. To this end, we have developed an analog of cyanide, with a 13CH3-reporter group attached to make methyl isocyanide. We describe the synthesis and use of 13C-methyl isocyanide as a probe of both bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. The 13C-methyl isocyanide probe can be used in a relatively high-throughput 1-D experiment to identify binders, but it can also be used to detect structural changes in the active site based on chemical shift changes, and potentially nuclear Overhauser effects between probe and inhibitor. PMID:23475666

  12. Brain and behavioural evidence for rest-activity cycles in Octopus vulgaris.

    PubMed

    Brown, Euan R; Piscopo, Stefania; De Stefano, Rosanna; Giuditta, Antonio

    2006-09-25

    Octopus vulgaris maintained under a 12/12h light/dark cycle exhibit a pronounced nocturnal activity pattern. Animals deprived of rest during the light period show a marked 'rebound' in activity in the following 24h. 'Active' octopuses attack faster than 'quiet' animals and brain activity recorded electrically intensifies during 'quiet' behaviour. Thus, in Octopus as in vertebrates, brain areas involved in memory or 'higher' processes exhibit 'off-line' activity during rest periods.

  13. The preparation and biological activity of methyl 5,6-epoxy-retinoate

    PubMed Central

    Morgan, B.; Thompson, J. N.

    1966-01-01

    1. Oxidation of methyl retinoate with monoperphthalic acid gave methyl 5,6-epoxyretinoate, obtained as pale-yellow crystals, m.p. 89°. 2. The structure of the epoxide was confirmed by its ultraviolet, infrared, nuclear-magnetic-resonance and mass spectra. 3. The biological properties of the epoxide were investigated in male and female rats, and were found to be qualitatively similar to those of retinoic acid and methyl retinoate. 4. When administered to male rats reared on a vitamin A-free diet, the epoxide permitted growth although it did not maintain good general health. 5. Rats given a vitamin A-free diet and supplements of the epoxide had degenerate testes. 6. Female rats, maintained on a vitamin A-free diet containing retinoic acid and given supplements of the epoxide during pregnancy, resorbed their foetuses and failed to deliver litters. 7. The threshold of the electroretinogram response in male rats reared on a vitamin A-free diet with supplements of the epoxide was elevated above normal and was similar to that of rats maintained with methyl retinoate. 8. The oral administration of the epoxy acid to rats did not result in the accumulation of the corresponding epoxy alcohol in their livers. PMID:16742464

  14. Methyl bromide release from activated carbon and the soil/water/carbon interface

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl Bromide (MB) is a major source of stratospheric bromine radical, a known depletor of ozone. The use of ozone-depleting chemicals, including MB, is regulated by the Montreal Protocol. Critical uses of MB are permitted, such as when postharvest fumigation is mandated by an importing country. Fo...

  15. Coronal Dynamic Activities in the Declining Phase of a Solar Cycle

    NASA Astrophysics Data System (ADS)

    Jang, Minhwan; Woods, T. N.; Hong, Sunhak; Choe, G. S.

    2016-12-01

    It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO/LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable second maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.

  16. Associations between prenatal physical activity, birth weight, and DNA methylation at genomically imprinted domains in a multiethnic newborn cohort.

    PubMed

    McCullough, Lauren E; Mendez, Michelle A; Miller, Erline E; Murtha, Amy P; Murphy, Susan K; Hoyo, Cathrine

    2015-01-01

    Birth weight is a commonly used indicator of the fetal environment and a predictor of future health outcomes. While the etiology of birth weight extremes is likely multifactorial, epidemiologic data suggest that prenatal physical activity (PA) may play an important role. The mechanisms underlying this association remain unresolved, although epigenetics has been proposed. This study aimed to estimate associations between prenatal PA, birth weight, and newborn DNA methylation levels at differentially methylated regions (DMRs) regulating 4 imprinted genes known to be important in fetal development. Study participants (N = 1281) were enrolled as part of the Newborn Epigenetics Study. Prenatal PA was ascertained using the Pregnancy Physical Activity Questionnaire, and birth weight data obtained from hospital records. Among 484 term mother-infant pairs, imprinted gene methylation levels were measured at DMRs using bisulfite pyrosequencing. Generalized linear and logistic regression models were used to estimate associations. After adjusting for preterm birth and race/ethnicity, we found that infants born to mothers in the highest quartile of total non-sedentary time had lower birth weight compared to infants of mothers in the lowest quartile (β = -81.16, SE = 42.02, P = 0.05). These associations appeared strongest among male infants (β = -125.40, SE = 58.10, P = 0.03). Methylation at the PLAGL1 DMR was related to total non-sedentary time (P < 0.05). Our findings confirm that prenatal PA is associated with reduced birth weight, and is the first study to support a role for imprinted gene plasticity in these associations. Larger studies are required.

  17. Is the Valles caldera entering a new cycle of activity?

    SciTech Connect

    Wolff, J.A.; Gardner, J.N.

    1995-05-01

    The Valles caldera formed during two major rhyolitic ignimbrite eruptive episodes (the Bandelier Tuff) at 1.61 and 1.22 Ma, after some 12 m.y. of activity in the Jemez Mountains volcanic field, New Mexico. Several subsequent eruptions between 1.22 and 0.52 Ma produced dominantly high-silica rhyolite lava domes and tephras within the caldera. These were followed by a dormancy of 0.46 m.y. prior to the most recent intracaldera activity, the longest hiatus since the inception of the Bandelier magma system at approximately 1.8 Ma. The youngest volcanic activity at approximately 60 ka produced the SW moat rhyolites, a series of lavas and tuffs that display abundant petrologic evidence of being newly generated melts. Petrographic textures conform closely to published predictions for silicic magmas generated by intrusion of basaltic magma into continental crust. The Valles caldera may currently be the site of renewed silicic magma generation, induced by intrusion of mafic magma at depth. Recent seismic investigations revealed the presence of a large low-velocity anomaly in the lower crust beneath the caldera. The generally aseismic character of the caldera, despite abundant regional seismicity, may be attributed to a heated crustal column, the local effect of 13 m.y. of magmatism and emplacement of mid-crustal plutons. 24 refs., 3 figs.

  18. Vitamin and mineral supplementation effect on muscular activity and cycling efficiency in master athletes.

    PubMed

    Louis, Julien; Hausswirth, Christophe; Bieuzen, François; Brisswalter, Jeanick

    2010-06-01

    The influence of vitamin and mineral complex supplementation on muscular activity and cycling efficiency was examined in elderly endurance-trained master athletes during a heavy cycling trial. Master athletes were randomly assigned in a double-blind process to 1 of 2 treatment groups: antioxidant supplementation (n = 8: As group) or placebo (n = 8: Pl group) for 21 days. After that time, each subject had to perform a 10-min session of cycling on a cycloergometer at a heavy constant intensity. Twenty-four to 48 h after this session, subjects performed an isometric maximal voluntary contraction before and immediately after a fatiguing strength training (leg press exercise) and the same 10-min cycling test after fatigue. Isometric maximal voluntary force (MVF) of knee extensors was assessed before and after fatigue. Electromyographic (EMG) activity of the vastus medialis, the vastus lateralis (VL), and the biceps femoris was recorded with surface EMG. The knee-extensors MVF after the fatiguing exercise was reduced in similar proportions for both groups (As, -10.9%; Pl, -11.3%, p < 0.05). This MVF loss was associated with a significant reduction in EMG frequency parameters for both groups, with a lower decrease for the As group. Muscular activity and cycling efficiency during the cycling bouts were affected by the treatment. Cycling efficiency decreased significantly and the oxygen uptake slow component was higher after the fatiguing exercise for both groups. Furthermore, a decrease in cycling efficiency was associated with an increase in VL activity. However, these changes were significantly lower for the As group. The results of the present study indicate an overall positive effect of vitamin and mineral complex supplementation on cycling efficiency after fatigue, in the endurance-trained elderly.

  19. CG methylated microarrays identify a novel methylated sequence bound by the CEBPB|ATF4 heterodimer that is active in vivo.

    PubMed

    Mann, Ishminder K; Chatterjee, Raghunath; Zhao, Jianfei; He, Ximiao; Weirauch, Matthew T; Hughes, Timothy R; Vinson, Charles

    2013-06-01

    To evaluate the effect of CG methylation on DNA binding of sequence-specific B-ZIP transcription factors (TFs) in a high-throughput manner, we enzymatically methylated the cytosine in the CG dinucleotide on protein binding microarrays. Two Agilent DNA array designs were used. One contained 40,000 features using de Bruijn sequences where each 8-mer occurs 32 times in various positions in the DNA sequence. The second contained 180,000 features with each CG containing 8-mer occurring three times. The first design was better for identification of binding motifs, while the second was better for quantification. Using this novel technology, we show that CG methylation enhanced binding for CEBPA and CEBPB and inhibited binding for CREB, ATF4, JUN, JUND, CEBPD, and CEBPG. The CEBPB|ATF4 heterodimer bound a novel motif CGAT|GCAA 10-fold better when methylated. The electrophoretic mobility shift assay (EMSA) confirmed these results. CEBPB ChIP-seq data using primary female mouse dermal fibroblasts with 50× methylome coverage for each strand indicate that the methylated sequences well-bound on the arrays are also bound in vivo. CEBPB bound 39% of the methylated canonical 10-mers ATTGC|GCAAT in the mouse genome. After ATF4 protein induction by thapsigargin which results in ER stress, CEBPB binds methylated CGAT|GCAA in vivo, recapitulating what was observed on the arrays. This methodology can be used to identify new methylated DNA sequences preferentially bound by TFs, which may be functional in vivo.

  20. The variability of coronal holes during two last cycles of solar activity

    NASA Astrophysics Data System (ADS)

    Prosovetsky, Dmitry

    Coronal holes (CH) well known as open magnetic field area are the important factor of space weather variability and geomagnetic disturbances in the Earth's magnetosphere. The properties of CH as well as related with them high-speed solar wind streams are defined by features of a configuration of a magnetic field and an atmosphere structure above. However, till now it is not clear, how these parameters vary during different cycles of solar activity and different phases of cycle development. In this paper the comparative examination of CH properties is carried out for minima of 22 and 23 cycles of solar activity. The observations data of UV and microwave emission at four frequencies together with measuring of a magnetic field and its extrapolation on high levels were studied. Some significant features were founded. It was noticed the middle-latitude and equatorial CH with largest area exists during large time of a cycle with an identical configuration of a large-scale magnetic field. CH of an identical configuration (e.g. elephant trunk) are observed in both various cycles of solar activity that reflects identical mechanisms of a global magnetic field formation in a cycle. Brightness temperatures at levels of chromosphere and the low corona in a CH of a cycle 23 minimum, on the average, are 50 percents less than temperature during cycle 22 minimum. It is found, that the large-scale magnetic field of the Sun in activity minimums is segmented by alternating areas of different polarity, and the magnetic fields of CH are one of segments. In cycle 22 minimum the meridional segments of the magnetic field related with CH were dominated. On the other hand during 23 cycle the latitudinal segments were dominated. Features of CH with the closed configuration of a magnetic field perhaps not are visible in UV and microwave emission. Visibility requirements of CH as dark features in UV concerning the quiet Sun are quasi-radiality of a magnetic field and its value ¿5 Gs were

  1. Selective inhibition of EZH2 by ZLD1039 blocks H3K27methylation and leads to potent anti-tumor activity in breast cancer

    PubMed Central

    Song, Xuejiao; Gao, Tiantao; Wang, Ningyu; Feng, Qiang; You, Xinyu; Ye, Tinghong; Lei, Qian; Zhu, Yongxia; Xiong, Menghua; Xia, Yong; Yang, Fangfang; Shi, Yaojie; Wei, Yuquan; Zhang, Lidan; Yu, Luoting

    2016-01-01

    Enhancer of zeste homolog 2 (EZH2) is a candidate oncogenic driver due to its prevalent overexpression and aberrant repression of tumor suppressor genes in diverse cancers. Therefore, blocking EZH2 enzyme activity may present a valid therapeutic strategy for the treatment of cancers with EZH2 overexpression including breast cancers. Here, we described ZLD1039 a potent, highly selective, and orally bioavailable small molecule inhibitor of EZH2, which inhibited breast tumor growth and metastasis. ZLD1039 considerably inhibited EZH2 methyltransferase activity with nanomolar potency, decreased global histone-3 lysine-27 (H3K27) methylation, and reactivated silenced tumor suppressors connected to increased survival of patients with breast cancer. Comparable to conditional silencing of EZH2, its inhibition by ZLD1039 decreased cell proliferation, cell cycle arrest, and induced apoptosis. Comparably, treatment of xenograft-bearing mice with ZLD1039 led to tumor growth regression and metastasis inhibition. These data confirmed the dependency of breast cancer progression on EZH2 activity and the usefulness of ZLD1039 as a promising treatment for breast cancer. PMID:26868841

  2. The activity cycle of 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Snodgrass, C.; Barrera, L.; Boehnhardt, H.; Guilbert-Lepoutre, A.; Hainaut, O.; Hutsemékers, D.; Jehin, E.; Meech, K.; Opitom, C.; Schulz, R.; Tozzi, G.; Tubiana, C.

    2014-07-01

    We present ground-based observations of comet 67P/Churyumov-Gerasimenko, target of the Rosetta mission, and an assessment on its activity levels. Based on imaging in the R-band, we measure the brightness of the coma within various apertures and use this to assess the amount of dust in the coma. We find that the comet begins to show detectable activity at a pre-perihelion distance from the Sun of 4.3 au, and then shows a smooth increase in production to a peak around one month after perihelion passage. The behaviour of the comet is consistent from one orbit to another, based on archival images taken over three apparitions, and we therefore use the heliocentric lightcurve to make predictions for the 2014/5 period while Rosetta is operating at the comet. We find that the Afρ parameter, measured within an aperture of radius 10,000 km at the comet, is proportional to r^{-3.2}, pre-perihelion [1]. We also attempt to make predictions on the gas production rate by fitting a model to the observed brightness values. This is done by assuming various parameters about the nucleus and dust, many of which are reasonably well constrained for 67P, and solving an energy balance equation that gives the sublimation rate of various ices as a function of solar illumination [2]. The model then links the gas production rate to the total amount of dust in the coma, and its brightness. We find that only a small fraction of the surface area (1.4 %) needs to be active for water sublimation, with an extra peak (up to 4 %) for a month either side of perihelion, while an even smaller area is producing CO_2 (0.04-0.09 %) [1]. The predictions can now be tested against new observations, and we will present the latest results from our 2014 monitoring of 67P. We are performing regular R-band imaging on the comet using the VLT, and early indications in March 2014 indicate that the comet does appear to have returned to activity as expected. By the time of the ACM meeting we will have around 4 months

  3. The Preference for Error-Free or Error-Prone Postreplication Repair in Saccharomyces cerevisiae Exposed to Low-Dose Methyl Methanesulfonate Is Cell Cycle Dependent

    PubMed Central

    Huang, Dongqing; Piening, Brian D.

    2013-01-01

    Cells employ error-free or error-prone postreplication repair (PRR) processes to tolerate DNA damage. Here, we present a genome-wide screen for sensitivity to 0.001% methyl methanesulfonate (MMS). This relatively low dose is of particular interest because wild-type cells exhibit no discernible phenotypes in response to treatment, yet PRR mutants are unique among repair mutants in their exquisite sensitivity to 0.001% MMS; thus, low-dose MMS treatment provides a distinctive opportunity to study postreplication repair processes. We show that upon exposure to low-dose MMS, a PRR-defective rad18Δ mutant stalls into a lengthy G2 arrest associated with the accumulation of single-stranded DNA (ssDNA) gaps. Consistent with previous results following UV-induced damage, reactivation of Rad18, even after prolonged G2 arrest, restores viability and genome integrity. We further show that PRR pathway preference in 0.001% MMS depends on timing and context; cells preferentially employ the error-free pathway in S phase and do not require MEC1-dependent checkpoint activation for survival. However, when PRR is restricted to the G2 phase, cells utilize REV3-dependent translesion synthesis, which requires a MEC1-dependent delay and results in significant hypermutability. PMID:23382077

  4. Active vibration and balance system for closed cycle thermodynamic machines

    NASA Technical Reports Server (NTRS)

    Qiu, Songgang (Inventor); Augenblick, John E. (Inventor); Peterson, Allen A. (Inventor); White, Maurice A. (Inventor)

    2004-01-01

    An active balance system is provided for counterbalancing vibrations of an axially reciprocating machine. The balance system includes a support member, a flexure assembly, a counterbalance mass, and a linear motor or an actuator. The support member is configured for attachment to the machine. The flexure assembly includes at least one flat spring having connections along a central portion and an outer peripheral portion. One of the central portion and the outer peripheral portion is fixedly mounted to the support member. The counterbalance mass is fixedly carried by the flexure assembly along another of the central portion and the outer peripheral portion. The linear motor has one of a stator and a mover fixedly mounted to the support member and another of the stator and the mover fixedly mounted to the counterbalance mass. The linear motor is operative to axially reciprocate the counterbalance mass. A method is also provided.

  5. TGEV nucleocapsid protein induces cell cycle arrest and apoptosis through activation of p53 signaling

    SciTech Connect

    Ding, Li; Huang, Yong; Du, Qian; Dong, Feng; Zhao, Xiaomin; Zhang, Wenlong; Xu, Xingang; Tong, Dewen

    2014-03-07

    Highlights: • TGEV N protein reduces cell viability by inducing cell cycle arrest and apoptosis. • TGEV N protein induces cell cycle arrest and apoptosis by regulating p53 signaling. • TGEV N protein plays important roles in TGEV-induced cell cycle arrest and apoptosis. - Abstract: Our previous studies showed that TGEV infection could induce cell cycle arrest and apoptosis via activation of p53 signaling in cultured host cells. However, it is unclear which viral gene causes these effects. In this study, we investigated the effects of TGEV nucleocapsid (N) protein on PK-15 cells. We found that TGEV N protein suppressed cell proliferation by causing cell cycle arrest at the S and G2/M phases and apoptosis. Characterization of various cellular proteins that are involved in regulating cell cycle progression demonstrated that the expression of N gene resulted in an accumulation of p53 and p21, which suppressed cyclin B1, cdc2 and cdk2 expression. Moreover, the expression of TGEV N gene promoted translocation of Bax to mitochondria, which in turn caused the release of cytochrome c, followed by activation of caspase-3, resulting in cell apoptosis in the transfected PK-15 cells following cell cycle arrest. Further studies showed that p53 inhibitor attenuated TGEV N protein induced cell cycle arrest at S and G2/M phases and apoptosis through reversing the expression changes of cdc2, cdk2 and cyclin B1 and the translocation changes of Bax and cytochrome c induced by TGEV N protein. Taken together, these results demonstrated that TGEV N protein might play an important role in TGEV infection-induced p53 activation and cell cycle arrest at the S and G2/M phases and apoptosis occurrence.

  6. The solar cycle variation of the rates of CMEs and related activity

    NASA Technical Reports Server (NTRS)

    Webb, David F.

    1991-01-01

    Coronal mass ejections (CMEs) are an important aspect of the physics of the corona and heliosphere. This paper presents results of a study of occurrence frequencies of CMEs and related activity tracers over more than a complete solar activity cycle. To properly estimate occurrence rates, observed CME rates must be corrected for instrument duty cycles, detection efficiencies away from the skyplane, mass detection thresholds, and geometrical considerations. These corrections are evaluated using CME data from 1976-1989 obtained with the Skylab, SMM and SOLWIND coronagraphs and the Helios-2 photometers. The major results are: (1) the occurrence rate of CMEs tends to track the activity cycle in both amplitude and phase; (2) the corrected rates from different instruments are reasonably consistent; and (3) over the long term, no one class of solar activity tracer is better correlated with CME rate than any other (with the possible exception of type II bursts).

  7. A viral gene that activates lytic cycle expression of Kaposi’s sarcoma-associated herpesvirus

    PubMed Central

    Sun, Ren; Lin, Su-Fang; Gradoville, Lyndle; Yuan, Yan; Zhu, Fanxiu; Miller, George

    1998-01-01

    Herpesviruses exist in two states, latency and a lytic productive cycle. Here we identify an immediate-early gene encoded by Kaposi’s sarcoma-associated herpesvirus (KSHV)/human herpesvirus eight (HHV8) that activates lytic cycle gene expression from the latent viral genome. The gene is a homologue of Rta, a transcriptional activator encoded by Epstein–Barr virus (EBV). KSHV/Rta activated KSHV early lytic genes, including virus-encoded interleukin 6 and polyadenylated nuclear RNA, and a late gene, small viral capsid antigen. In cells dually infected with Epstein–Barr virus and KSHV, each Rta activated only autologous lytic cycle genes. Expression of viral cytokines under control of the KSHV/Rta gene is likely to contribute to the pathogenesis of KSHV-associated diseases. PMID:9724796

  8. Effects of Space Weather on Biomedical Parameters during the Solar Activity Cycles 23-24.

    PubMed

    Ragul'skaya, M V; Rudenchik, E A; Chibisov, S M; Gromozova, E N

    2015-06-01

    The results of long-term (1998-2012) biomedical monitoring of the biotropic effects of space weather are discussed. A drastic change in statistical distribution parameters in the middle of 2005 was revealed that did not conform to usual sinusoidal distribution of the biomedical data reflecting changes in the number of solar spots over a solar activity cycle. The dynamics of space weather of 2001-2012 is analyzed. The authors hypothesize that the actual change in statistical distributions corresponds to the adaptation reaction of the biosphere to nonstandard geophysical characteristics of the 24th solar activity cycle and the probable long-term decrease in solar activity up to 2067.

  9. Hysteresis of indices of solar and ionospheric activity during 11-year cycles

    NASA Astrophysics Data System (ADS)

    Bruevich, E. A.; Kazachevskaya, T. V.; Katyushina, V. V.; Nusinov, A. A.; Yakunina, G. V.

    2016-12-01

    The effects of hysteresis, which is a manifestation of ambiguous relationships between different solar activity indices during the rising and declining phases of solar cycles, are analyzed. The paper addresses the indices characterizing radiation from the solar photosphere, chromosphere, and corona, and the ionospheric indices. The 21st, 22nd, and 23rd solar cycles, which significantly differ from each other in amplitude, exhibit different extents of hysteresis.

  10. Evaluation of HOx sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated ecosystem

    NASA Astrophysics Data System (ADS)

    Kim, S.; Wolfe, G. M.; Mauldin, L.; Cantrell, C.; Guenther, A.; Karl, T.; Turnipseed, A.; Greenberg, J.; Hall, S. R.; Ullmann, K.; Apel, E.; Hornbrook, R.; Kajii, Y.; Nakashima, Y.; Keutsch, F. N.; DiGangi, J. P.; Henry, S. B.; Kaser, L.; Schnitzhofer, R.; Graus, M.; Hansel, A.

    2012-06-01

    We present a detailed analysis of OH and HO2 observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen)-ROCS (Rocky Mountain Organic Carbon Study) 2010 field campaign at the Manitou Forest Observatory (MFO), which is a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM) was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO) can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 5. When the UWCM calculation is constrained by measured HO2, model calculated OH is in reasonable agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying unknown HO2

  11. Evaluation of HOx sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated ecosystem

    NASA Astrophysics Data System (ADS)

    Kim, S.; Wolfe, G. M.; Mauldin, L.; Cantrell, C.; Guenther, A.; Karl, T.; Turnipseed, A.; Greenberg, J.; Hall, S. R.; Ullmann, K.; Apel, E.; Hornbrook, R.; Kajii, Y.; Nakashima, Y.; Keutsch, F. N.; DiGangi, J. P.; Henry, S. B.; Kaser, L.; Schnitzhofer, R.; Graus, M.; Hansel, A.; Zheng, W.; Flocke, F. F.

    2013-02-01

    We present a detailed analysis of OH observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen)-ROCS (Rocky Mountain Organic Carbon Study) 2010 field campaign at the Manitou Forest Observatory (MFO), which is a 2-methyl-3-butene-2-ol (MBO) and monoterpene (MT) dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM) was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO) can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 4. When the UWCM calculation is constrained by measured HO2, model calculated OH is in better agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying unknown HO2 sources. These

  12. Relationship between skin temperature and muscle activation during incremental cycle exercise.

    PubMed

    Priego Quesada, Jose I; Carpes, Felipe P; Bini, Rodrigo R; Salvador Palmer, Rosario; Pérez-Soriano, Pedro; Cibrián Ortiz de Anda, Rosa M

    2015-02-01

    While different studies showed that better fitness level adds to the efficiency of the thermoregulatory system, the relationship between muscular effort and skin temperature is still unknown. Therefore, the present study assessed the relationship between neuromuscular activation and skin temperature during cycle exercise. Ten physically active participants performed an incremental workload cycling test to exhaustion while neuromuscular activations were recorded (via surface electromyography - EMG) from rectus femoris, vastus lateralis, biceps femoris and gastrocnemius medialis. Thermographic images were recorded before, immediately after and 10 min after finishing the cycling test, at four body regions of interest corresponding to the muscles where neuromuscular activations were monitored. Frequency band analysis was conducted to assess spectral properties of EMG signals in order to infer on priority in recruitment of motor units. Significant inverse relationship between changes in skin temperature and changes in overall neuromuscular activation for vastus lateralis was observed (r<-0.5 and p<0.04). Significant positive relationship was observed between skin temperature and low frequency components of neuromuscular activation from vastus lateralis (r>0.7 and p<0.01). Participants with larger overall activation and reduced low frequency component for vastus lateralis activation presented a better adaptive response of their thermoregulatory system by showing fewer changes in skin temperature after incremental cycling test.

  13. Relationships between solar activity and climate change. [sunspot cycle effects on lower atmosphere

    NASA Technical Reports Server (NTRS)

    Roberts, W. O.

    1974-01-01

    Recurrent droughts are related to the double sunspot cycle. It is suggested that high solar activity generally increases meridional circulations and blocking patterns at high and intermediate latitudes, especially in winter. This effect is related to the sudden formation of cirrus clouds during strong geomagnetic activity that originates in the solar corpuscular emission.

  14. Body temperature and physical activity correlates of the menstrual cycle in Chacma Baboons (Papio hamadryas ursinus).

    PubMed

    Nyakudya, Trevor T; Fuller, Andrea; Meyer, Leith C R; Maloney, Shane K; Mitchell, Duncan

    2012-12-01

    We investigated the temporal relationship between abdominal temperature, physical activity, perineal swelling, and urinary progesterone and estradiol concentrations over the menstrual cycle in unrestrained captive baboons. Using a miniature temperature-sensitive data logger surgically implanted in the abdominal cavity and an activity data logger implanted subcutaneously on the trunk, we measured, continuously over 6 months at 10-min intervals, abdominal temperature and physical activity patterns in four female adult baboons Papio hamadryas ursinus (12.9-19.9 kg), in cages in an indoor animal facility (22-25°C). We monitored menstrual bleeding and perineal swelling changes, and measured urinary progesterone and estradiol concentrations, daily for up to 6 months, to ascertain the stage and length of the menstrual cycle. The menstrual cycle was 36 ± 2 days (mean ± SD) long and the baboons exhibited cyclic changes in perineal swellings, abdominal temperature, physical activity, urinary progesterone, and estradiol concentrations over the cycle. Mean 24-hr abdominal temperature during the luteal phase was significantly higher than during the periovulatory phase (ANOVA, F((2, 9)) = 4.7; P = 0.04), but not different to that during the proliferative phase. Physical activity followed a similar pattern, with mean 24-hr physical activity almost twice as high in the luteal than in the periovulatory phase (ANOVA, P = 0.58; F((2, 12)) = 5.8). We have characterized correlates of the menstrual cycle in baboons and shown, for the first time, a rhythm of physical activity and abdominal temperature over the menstrual cycle, with a nadir of temperature and activity at ovulation.

  15. Activation of water soluble amines by halogens for trapping methyl radioactive iodine from air streams

    DOEpatents

    Deitz, Victor R.; Blachly, Charles H.

    1977-01-01

    Gas adsorbent charcoals impregnated with an aqueous solution of the reaction product of a tertiary amine and elemental iodine or bromine are better than 99 per cent efficient in trapping methyl iodine.sup.131. The chemical addition of iodine or bromine to the tertiary amine molecule increases the efficiency of the impregnated charcoal as a trapping agent, and in conjunction with the high flash point of the tertiary amine raises the ignition temperature of the impregnated charcoal.

  16. CMTM5 exhibits tumor suppressor activity through promoter methylation in oral squamous cell carcinoma

    SciTech Connect

    Zhang, Heyu; Nan, Xu; Li, Xuefen; Chen, Yan; Zhang, Jianyun; Sun, Lisha; Han, Wenlin; Li, Tiejun

    2014-05-02

    Highlights: • Down-regulation of CMTM5 expression in OSCC tissues was found. • The promoter methylation status of CMTM5 was measured. • CMTM5-v1 inhibited cell proliferation and migration and induced apoptosis. • CMTM5 might act as a putative tumor suppressor gene in OSCC. - Abstract: Oral squamous cell carcinoma (OSCC) is one of the most common types of malignancies in the head and neck region. CKLF-like MARVEL transmembrane domain-containing member 5 (CMTM5) has been recently implicated as a tumor suppressor gene in several cancer types. Herein, we examined the expression and function of CMTM5 in oral squamous cell carcinoma. CMTM5 was down-regulated in oral squamous cell lines and tumor samples from patients with promoter methylation. Treatment with the demethylating agent 5-aza-2′-deoxycytidine restored CMTM5 expression. In the OSCC cell lines CAL27 and GNM, the ectopic expression of CMTM5-v1 strongly inhibited cell proliferation and migration and induced apoptosis. In addition, CMTM5-v1 inhibited tumor formation in vivo. Therefore, CMTM5 might act as a putative tumor suppressor gene through promoter methylation in oral squamous cell carcinoma.

  17. Cell-cycle coupled expansion of AR activity promotes cancer progression

    PubMed Central

    McNair, Christopher; Urbanucci, Alfonso; Comstock, Clay E.S.; Augello, Michael A.; Goodwin, Jonathan F.; Launchbury, Rosalind; Zhao, Shuang; Schiewer, Mathew J.; Ertel, Adam; Karnes, Jeffrey; Davicioni, Elai; Wang, Liguo; Wang, Qianben; Mills, Ian G.; Feng, Felix Y.; Li, Wei; Carroll, Jason S.; Knudsen, Karen E.

    2016-01-01

    The androgen receptor (AR) is required for prostate cancer (PCa) survival and progression, and ablation of AR activity is the first line of therapeutic intervention for disseminated disease. While initially effective, recurrent tumors ultimately arise for which there is no durable cure. Despite the dependence of PCa on AR activity throughout the course of disease, delineation of the AR-dependent transcriptional network that governs disease progression remains elusive, and the function of AR in mitotically active cells is not well understood. Analyzing AR activity as a function of cell cycle revealed an unexpected and highly expanded repertoire of AR-regulated gene networks in actively cycling cells. New AR functions segregated into two major clusters: those that are specific to cycling cells and retained throughout the mitotic cell cycle (“Cell Cycle Common”), versus those that were specifically enriched in a subset of cell cycle phases (“Phase Restricted”). Further analyses identified previously unrecognized AR functions in major pathways associated with clinical PCa progression. Illustrating the impact of these unmasked AR-driven pathways, dihydroceramide-desaturase 1 (DEGS1) was identified as an AR regulated gene in mitotically active cells that promoted pro-metastatic phenotypes, and in advanced PCa proved to be highly associated with development of metastases, recurrence after therapeutic intervention, and reduced overall survival. Taken together, these findings delineate AR function in mitotically active tumor cells, thus providing critical insight into the molecular basis by which AR promotes development of lethal PCa and nominate new avenues for therapeutic intervention. PMID:27669432

  18. Isolation of methyl syringate as a specific aflatoxin production inhibitor from the essential oil of Betula alba and aflatoxin production inhibitory activities of its related compounds.

    PubMed

    Jermnak, Usuma; Yoshinari, Tomoya; Sugiyama, Yasumasa; Tsuyuki, Rie; Nagasawa, Hiromichi; Sakuda, Shohei

    2012-02-15

    Methyl syringate was isolated from the essential oil of Betula alba as an aflatoxin production inhibitor. It inhibited aflatoxin production of Aspergillus parasiticus and Aspergillus flavus with IC(50) values of 0.9 and 0.8 mM, respectively, without significantly inhibiting fungal growth. Methyl syringate reduced mRNA levels of genes (aflR, pksA, and omtB) [corrected] encoding proteins required for aflatoxin biosynthesis. Methyl gallate, methyl 3,4,5-trimethoxybenzoate, and methyl 3-O-methylgallate inhibited both aflatoxin production and fungal growth of A. parasiticus and A. flavus. However, their acids and syringic acid did not inhibit aflatoxin production and growth of A. parasiticus significantly, although gallic acid inhibited aflatoxin production of A. flavus with selectivity. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of methyl syringate was much weaker than that of gallic acid. These results showed that methyl syringate has a unique inhibitory activity toward aflatoxin production with a different mode of action from that of gallic acid.

  19. Synthesis, antimicrobial and anti-biofilm activities of novel Schiff base analogues derived from methyl-12-aminooctadec-9-enoate.

    PubMed

    Mohini, Y; Prasad, R B N; Karuna, M S L; Poornachandra, Y; Ganesh Kumar, C

    2014-11-15

    A novel library of Schiff base analogues (5a-q) were synthesized by the condensation of methyl-12-aminooctadec-9-enoate and different substituted aromatic aldehydes. The synthesized compounds were thoroughly characterized by spectroscopic techniques (FT-IR, (1)H NMR, (13)C NMR, ESI-MS and HRMS). The Schiff base analogues with different substitutions were screened for in vitro antibacterial activity against 7 different bacterial strains. Among these, the compounds with electron withdrawing substituent, namely chlorine (5a) and electron donating substituents, namely hydroxy (5 n) and methoxy (5 o), were found to exhibit excellent to good antimicrobial activities (MIC value 9-18 μM) against Staphylococcus aureus MTCC 96, Staphylococcus aureus MLS-16 MTCC 2940 and Bacillus subtilis MTCC 121. The products were also screened for anti-biofilm and MBC (Minimum Bactericidal Concentration) activities which exhibited promising activities.

  20. Inhibition of cathepsin S confers sensitivity to methyl protodioscin in oral cancer cells via activation of p38 MAPK/JNK signaling pathways

    PubMed Central

    Hsieh, Ming-Ju; Lin, Chiao-Wen; Chen, Mu-Kuan; Chien, Su-Yu; Lo, Yu-Sheng; Chuang, Yi-Ching; Hsi, Yi-Ting; Lin, Chia-Chieh; Chen, Jui-Chieh; Yang, Shun-Fa

    2017-01-01

    Oral cancer is one of the most common cancers in the world. Approximately 90% of oral cancers are subtyped to oral squamous cell carcinoma (OSCC). Despite advances in diagnostic techniques and improvement in treatment modalities, the prognosis remains poor. Therefore, an effective chemotherapy mechanism that enhances tumor sensitivity to chemotherapeutics is urgently needed. Methyl protodioscin (MP) is a furostanol bisglycoside with a wide range of beneficial effects, including anti-inflammatory and anti-cancer properties. The aim of the present study was to determine the antitumor activity of MP on OSCC and its underlying mechanisms. Our results show that treatment of OSCC cells with MP potently inhibited cell viability. Moreover, MP leading to cell cycle arrest at G2/M phase, which subsequently activates caspase-3, -8, -9 and PARP to induce cell apoptosis. Meanwhile, we also demonstrate that MP induces a robust autophagy in OSCC cells. The results indicate cathepsin S (CTSS) is involved in MP-induced apoptosis and autophagy by modulation of p38 MAPK and JNK1/2 pathways. These findings may provide rationale to combine MP with CTSS blockade for the effective treatment of OSCC. PMID:28327651

  1. The chemopreventive activity of apple against carcinogenesis: antioxidant activity and cell cycle control.

    PubMed

    Ribeiro, Flávia A P; Gomes de Moura, Carolina F; Aguiar, Odair; de Oliveira, Flavia; Spadari, Regina C; Oliveira, Nara R C; Oshima, Celina T F; Ribeiro, Daniel A

    2014-09-01

    Apples and their derivatives are rich in phytochemicals, including flavonoids (catechins, flavonols, quercetin) and phenolic acids (quercetin glycosides, catechin, epicatechin, procyanidins), vitamins, and fibers, that confer an important antioxidant property. Chemoprevention is defined by the use of natural or synthetic agents to interfere with the progression, reverse, or inhibit carcinogenesis, thereby reducing the risk of developing clinically invasive disease. The aim of this article is to present data generated from the use of apples as a chemopreventive agent in carcinogenesis using in-vivo and in-vitro test systems. Apple and its bioactive compounds can exert chemopreventive properties as a result of antioxidant activity and cell cycle control. However, future focus of research on apple such as identifying the specific phytochemical responsible for the anticarcinogenic effect, timing of consumption, and adequate amount of apples to achieve the best preventive effect using human large randomized-controlled trials is needed. Furthermore, animal studies are also relevant for better understanding the role of this fruit in human health as well as modulation of degenerative diseases such as cancer. Therefore, this area warrants further investigation as a new way of thinking, which would apply not only to apples but also to other fruit used as promising therapeutic agents against human diseases.

  2. Discovery of an activity cycle in the solar analog HD 45184. Exploring Balmer and metallic lines as activity proxy candidates

    NASA Astrophysics Data System (ADS)

    Flores, M.; González, J. F.; Jaque Arancibia, M.; Buccino, A.; Saffe, C.

    2016-05-01

    Context. Most stellar activity cycles similar to that found in the Sun have been detected by using the chromospheric Ca ii H&K lines as stellar activity proxies. However, it is unclear whether such activity cycles can be identified using other optical lines. Aims: We aim to detect activity cycles in solar-analog stars and determine whether they can be identified through other optical lines, such as Fe II and Balmer lines. We study the solar-analog star HD 45184 using HARPS spectra. The temporal coverage and high quality of the spectra allow us to detect both long- and short-term activity variations. Methods: We analysed the activity signatures of HD 45184 by using 291 HARPS spectra obtained between 2003 and 2014. To search for line-core flux variations, we focused on Ca ii H&K and Balmer Hα and Hβ lines, which are typically used as optical chromospheric activity indicators. We calculated the HARPS-S index from Ca ii H&K lines and converted it into the Mount Wilson scale. In addition, we also considered the equivalent widths of Balmer lines as activity indicators. Moreover, we analysed the possible variability of Fe ii and other metallic lines in the optical spectra. The spectral variations were analysed for periodicity using the Lomb-Scargle periodogram. Results: We report for the first time a long-term 5.14-yr activity cycle in the solar-analog star HD 45184 derived from Mount Wilson S index. This makes HD 45184 one of most similar stars to the Sun with a known activity cycle. The variation is also evident in the first lines of the Balmer series, which do not always show a correlation with activity in solar-type stars. Notably, unlike the solar case, we also found that the equivalent widths of the high photospheric Fe ii lines (4924 Å, 5018 Å and 5169 Å) are modulated (±2 mÅ) by the chromospheric cycle of the star. These metallic lines show variations above 4σ in the rms spectrum, while some Ba ii and Ti ii lines present variations at 3σ level, which

  3. Phosphate-Activated Cyclin-Dependent Kinase Stabilizes G1 Cyclin To Trigger Cell Cycle Entry

    PubMed Central

    Menoyo, S.; Ricco, N.; Bru, S.; Hernández-Ortega, S.; Escoté, X.; Aldea, M.

    2013-01-01

    G1 cyclins, in association with a cyclin-dependent kinase (CDK), are universal activators of the transcriptional G1-S machinery during entry into the cell cycle. Regulation of cyclin degradation is crucial for coordinating progression through the cell cycle, but the mechanisms that modulate cyclin stability to control cell cycle entry are still unknown. Here, we show that a lack of phosphate downregulates Cln3 cyclin and leads to G1 arrest in Saccharomyces cerevisiae. The stability of Cln3 protein is diminished in strains with low activity of Pho85, a phosphate-sensing CDK. Cln3 is an in vitro substrate of Pho85, and both proteins interact in vivo. More interestingly, cells that carry a CLN3 allele encoding aspartic acid substitutions at the sites of Pho85 phosphorylation maintain high levels of Cln3 independently of Pho85 activity. Moreover, these cells do not properly arrest in G1 in the absence of phosphate and they die prematurely. Finally, the activity of Pho85 is essential for accumulating Cln3 and for reentering the cell cycle after phosphate refeeding. Taken together, our data indicate that Cln3 is a molecular target of the Pho85 kinase that is required to modulate cell cycle entry in response to environmental changes in nutrient availability. PMID:23339867

  4. Transitions into and out of daylight saving time compromise sleep and the rest-activity cycles

    PubMed Central

    Lahti, Tuuli A; Leppämäki, Sami; Lönnqvist, Jouko; Partonen, Timo

    2008-01-01

    Background The aim of this study was to analyze the effects of transition out of and into daylight saving time on the rest-activity cycles and sleep. Rest-activity cycles of nine healthy participants aged 20 to 40 years were measured around transitions out of and into daylight saving time on fall 2005 and spring 2006 respectively. Rest-activity cycles were measured using wrist-worn accelerometers. The participants filled in the Morningness-Eveningness and Seasonal Pattern Assessment Questionnaires before starting the study and kept a sleep diary during the study. Results Fall transition was more disturbing for the more morning type and spring transition for the more evening type of persons. Individuals having a higher global seasonality score suffered more from the transitions. Conclusion Transitions out of and into daylight saving time enhanced night-time restlessness and thereby compromised the quality of sleep. PMID:18269740

  5. Two Types of Coronal Bright Points in the 24-th Cycle of Solar Activity

    NASA Astrophysics Data System (ADS)

    Sherdanov, Chori T.; Minenko, Ekaterina P.; Tillaboev, A. M.; Sattarov, Isroil

    We applied an automatic program for identification of coronal bright points (CBPs) to the data obtained by SOHO/EIT observations taken at the wavelength 195 Å, in the time interval from the end of the 23rd to the early 24th solar cycle. We studied the total number of CBPs and its variations at the beginning of the given cycle of solar activity, so that the development of the solar activity could be predicted with the use of CBPs. For a primary reference point for the 24th solar cycle, we took the emergence of a high-latitude sunspot with the reversed polarity, which appeared in January, 2008. We show that the observed number of CBPs reaches the highest point around the minimum of the solar activity, which in turn may result from the effect of visibility. The minimum solar activity at this time provides the opportunity to register the number of CBPs with the highest accuracy, with its uniform latitudinal distribution. We also study the properties of CBPs in a new 24th cycle of solar activity. It is shown that variations in the cyclic curve of the number of coronal bright points associated with variations in the solar activity, for the latitudes of the quiet Sun to be anticorrelation characteristic changes in the number CBPs to the solar activity, and the observational data are for the regions of active formations on the Sun almost identical on character on the equatorial latitude, but this have lightly expressed character in high-latitude zone. To explain the cyclic curves of variation in the number of coronal bright points in connection with the solar cycle in different latitudinal zones, we suggest a hypothesis of the existence of two types of coronal bright points: those associated with the quiet corona and those related to active formations.

  6. Low-intensity cycling affects the muscle activation pattern of consequent countermovement jumps.

    PubMed

    Marquez, Gonzalo J; Mon, Javier; Acero, Rafael M; Sanchez, Jose A; Fernandez-del-Olmo, Miguel

    2009-08-01

    Players (eg, basketball, soccer, and football) often use a static bicycle during a game to maintain warming. However, the effectiveness of this procedure has not been addressed in the literature. Thus, it remains unknown whether low-intensity cycling movement can affect explosive movement performance. In this study, 10 male subjects performed countermovement jumps before and after a 15-minutes cycling bout at 35% of their maximal power output. Three sessions were tested for 3 different cadences of cycling: freely chosen cadence, 20% lower than freely chosen cadence (FCC-20%), and 20% higher than freely chosen cadence (FCC+20%). Jump height, kinematics, and electromyogram were recorded simultaneously during the countermovement jumps. The results showed a significant decreasing in the height of countermovement jump after cycling at freely chosen cadence and FCC-20% (p = 0.03 and p = 0.04, respectively), but not for FCC+20% cadences. The electromyographic parameters suggest that changes in the countermovement jump after cycling can be attributed to alteration of the pattern of activation and may be modulated by the preceding cycling cadence. Our study indicates that to avoid a possible negative effect of the cycling in the subsequent explosive movements, a cadence 20% higher than the preferred cadence must be used.

  7. A new solar activity parameter and the strength of 5-cycle periodicity

    NASA Astrophysics Data System (ADS)

    Du, Z. L.

    2006-10-01

    A weak 5-cycle periodicity ( r = -0.64) is found in the maximum amplitudes of the modern era sunspot cycles (11-23), slightly stronger than the 8-cycle (Gleissberg) periodicity ( r = 0.60). We propose a new parameter called 'effective duration', defined as the total sunspot numbers in a cycle divided by the maximum amplitude. This parameter has two advantages: one is that it is almost independent of the exact definition of minimum timing; another is that the maximum amplitude is found to be highly correlated ( r = 0.86) with this parameter five cycles before, when applied to the smoothed monthly mean sunspot numbers in modern era. Implied is that this parameter carries some information of the amplitude five cycles later, and may become one of the parameters to study solar activity and the theory of solar dynamo. With the relationship above, the amplitude of cycle 24 is estimated to be 115.7 ± 19.7, where the error is the standard error.

  8. Breathing of heliospheric structures triggered by the solar-cycle activity

    NASA Astrophysics Data System (ADS)

    Scherer, K.; Fahr, H. J.

    2003-06-01

    Solar wind ram pressure variations occuring within the solar activity cycle are communicated to the outer heliosphere as complicated time-variabilities, but repeating its typical form with the activity period of about 11 years. At outer heliospheric regions, the main surviving solar cycle feature is a periodic variation of the solar wind dynamical pressure or momentum flow, as clearly recognized by observations of the VOYAGER-1/2 space probes. This long-periodic variation of the solar wind dynamical pressure is modeled here through application of appropriately time-dependent inner boundary conditions within our multifluid code to describe the solar wind - interstellar medium interaction. As we can show, it takes several solar cycles until the heliospheric structures adapt to an average location about which they carry out a periodic breathing, however, lagged in phase with respect to the solar cycle. The dynamically active heliosphere behaves differently from a static heliosphere and especially shows a historic hysteresis in the sense that the shock structures move out to larger distances than explained by the average ram pressure. Obviously, additional energies are pumped into the heliosheath by means of density and pressure waves which are excited. These waves travel outwards through the interface from the termination shock towards the bow shock. Depending on longitude, the heliospheric sheath region memorizes 2-3 (upwind) and up to 6-7 (downwind) preceding solar activity cycles, i.e. the cycle-induced waves need corresponding travel times for the passage over the heliosheath. Within our multifluid code we also adequately describe the solar cycle variations in the energy distributions of anomalous and galactic cosmic rays, respectively. According to these results the distribution of these high energetic species cannot be correctly described on the basis of the actually prevailing solar wind conditions.

  9. Core promoter analysis of porcine Six1 gene and its regulation of the promoter activity by CpG methylation.

    PubMed

    Wu, Wangjun; Ren, Zhuqing; Liu, Honglin; Wang, Linjie; Huang, Ruihua; Chen, Jie; Zhang, Lin; Li, Pinghua; Xiong, Yuanzhu

    2013-10-25

    Six1, an evolutionary conserved transcription factor, has been shown to play an important role in organogenesis and diseases. However, no reports were shown to investigate its transcriptional regulatory mechanisms. In the present study, we first identified porcine Six1 gene core promoter region (+170/-360) using luciferase reporter assay system and found that promoter activities were significantly higher in the mouse myoblast C2C12 cells than that in the mouse fibroblast C3H10T1/2 cells, implying that Six1 promoter could possess muscle-specific characteristics. Moreover, our results showed that promoter activities of Six1 were decreased as induction of differentiation of C2C12 cells, which was accompanied by the down-regulation of mRNA expression of Six1 gene. In addition, we found that the DNA methylation of Six1 promoters in vitro obviously influences the promoter activities and the DNA methylation level of Six1 promoter core region was negatively correlated to Six1 gene expression in vivo. Taken together, we preliminarily clarified transcriptional regulatory mechanisms of Six1 gene, which should be useful for investigating its subtle transcriptional regulatory mechanisms in the future. On the other hand, based on Six1 involved in tumorigenesis, our data also provide a genetic foundation to control the generation of diseases via pursuing Six1 as therapeutic target gene.

  10. The Methyltransferase Activity of Clr4Suv39h triggers RNAi Independently of Histone H3K9 Methylation

    PubMed Central

    Gerace, Erica L.; Halic, Mario; Moazed, Danesh

    2010-01-01

    Summary In fission yeast, pericentromeric dg and dh repeats are transcribed and give rise to small interfering RNAs (siRNAs) by a mechanism that depends on the Clr4suv39h histone H3 lysine 9 (H3K9) methyltransferase. Here we show that Clr4 activity promotes the assembly of a tripartite complex composed of the Clr4-containing CLRC complex and complexes involved in siRNA generation. However, unlike dh siRNAs, dg siRNAs accumulate to near wild-type levels in cells with H3K9 substitutions that cannot be methylated. Thus, Clr4 activity controls siRNA amplification from the different repeat regions by different mechanisms, H3K9 methylation-dependent versus -independent. Furthermore, artificial tethering of Rik1, a core subunit of the CLRC complex, to a euchromatic RNA mediates RNAi-dependent silencing that partially bypasses the requirement for other CLRC subunits. These findings establish Rik1 as a key link between CLRC and RNAi and reveal distinct centromeric siRNA amplification mechanisms that depend on the Clr4 methyltransferase activity. PMID:20705239

  11. Impact of Stepwise NH2-Methylation of Triapine on the Physicochemical Properties, Anticancer Activity, and Resistance Circumvention

    PubMed Central

    2016-01-01

    One of the most promising classes of iron chelators are α-N-heterocyclic thiosemicarbazones with Triapine as the most prominent representative. In several clinical trials Triapine showed anticancer activity against hematological diseases, however, studies on solid tumors failed due to widely unknown reasons. Some years ago, it was recognized that “terminal dimethylation” of thiosemicarbazones can lead to a more than 100-fold increased activity, probably due to interactions with cellular copper depots. To better understand the structural requirements for the switch to nanomolar cytotoxicity, we systematically synthesized all eight possible N-methylated derivatives of Triapine and investigated their potential against Triapine-sensitive as well as -resistant cell lines. While only the “completely” methylated compound exerted nanomolar activity, the data revealed that all compounds with at least one N-dimethylation were not affected by acquired Triapine resistance. In addition, these compounds were highly synergistic with copper treatment accompanied by induction of reactive oxygen species and massive necrotic cell death. PMID:27336684

  12. Mg II Chromospheric Emission Line Bisectors Of HD39801 And Its Relation With The Activity Cycle

    NASA Astrophysics Data System (ADS)

    García García, Leonardo Enrique; Pérez Martínez, M. Isabel

    2016-07-01

    Betelgeuse is a cool star of spectral type M and luminosity class I. In the present work, the activity cycle of Betelgeuse was obtained from the integrated emission flux of the Mg II H and K lines, using more than 250 spectra taken from the International Ultraviolet Explorer (IUE) online database. Of which it was found, based on a Lomb Scargle periodogram, a cycle of 16 years, along with 2 sub-cycles with a period of the order of 0.60 and 0.65 years, which may be due to turbulence or possible stellar flares. In addition, an analysis of line asymmetry was made by means of the chromospheric emission line bisectors, due to the strong self-absorption observed in this lines, the blue and red wings were analyzed independently. In order to measure such asymmetry, a "line shift" was calculated, from which several cycles of variability were obtained from a Lomb Scargle periodogram, spanning from few months to 4 years. In the sense, the most significant cycle is about 0.44 and 0.33 years in the blue and red wing respectively. It is worth noting, that the rotation period of the star doesn't play an important role in the variability of the Mg II lines. This technique provides us with a new way to study activity cycles of evolved stars.

  13. Inhibition of cholinesterase activity by azinphos-methyl in two freshwater invertebrates: Biomphalaria glabrata and Lumbriculus variegatus.

    PubMed

    Kristoff, Gisela; Guerrero, Noemi Verrengia; de D'Angelo, Ana María Pechén; Cochón, Adriana C

    2006-05-15

    In this study, some biochemical features and the extent of inhibition induced by the organophosphorous pesticide azinphos-methyl on the cholinesterase (ChE) activity present in whole soft tissue of two freshwater invertebrate species, the gastropod Biomphalaria glabrata and the oligochaete Lumbriculus variegatus were investigated. Both invertebrate organisms presented marked differences in ChE activity, type of enzymes and subcellular location. Acetylthiocholine was the substrate preferred by B. glabrata ChE. The enzyme activity was located preferentially in the supernatant of 11,000 x g centrifugation and was inhibited by increasing concentrations of substrate but not by iso-OMPA. Results showed that there were progressive inhibitions of the enzyme activity, with values 21%, 59%, 72%, 76%, and 82% lower than the control at levels of 1, 10, 50, 100 and 1000 microM of eserine, respectively. In contrast, L. variegatus ChE activity was distributed both in the supernatant and pellet fractions, with values approximately 6 and 20 times higher than B. glabrata, respectively. Studies with butyrylthiocholine and iso-OMPA suggested that about 72% of the activity corresponded to butyrylcholinesterase. A strong enzyme inhibition (88-94%) was found at low eserine concentrations (1-10 microM). ChE activity from L. variegatus and B. glabrata was inhibited by in vivo exposure to azinphos-methyl suggesting that both species can form the oxon derivative of this pesticide. However, both invertebrate species showed a very different susceptibility to the insecticide. The NOEC and EIC50 values were 500 and 1000 times lower for L. variegatus than for B. glabrata, reflecting that the oligochaetes were much more sensitive organisms. A different pattern was also observed for the recovery of the enzymatic activity when the organisms were transferred to clean water. The recuperation process was faster for the oligochaetes than for the gastropods. Mortality was not observed in either of the

  14. Changes in urinary amino acids excretion in relationship with muscle activity markers over a professional cycling stage race: in search of fatigue markers.

    PubMed

    Corsetti, Roberto; Barassi, Alessandra; Perego, Silvia; Sansoni, Veronica; Rossi, Alessandra; Damele, Clara Anna Linda; Melzi D'Eril, Gianlodovico; Banfi, Giuseppe; Lombardi, Giovanni

    2016-01-01

    The aim of this study was to identify the relationship between metabolic effort, muscular damage/activity indices, and urinary amino acids profile over the course of a strenuous prolonged endurance activity, as a cycling stage race is, in order to identify possible fatigue markers. Nine professional cyclists belonging to a single team, competing in the Giro d'Italia cycling stage race, were anthropometrically characterized and sampled for blood and urine the day before the race started, and on days 12 and 23 of the race. Diet was kept the same over the race, and power output and energy expenditure were recorded. Sera were assayed for muscle markers (lactate dehydrogenase, aspartate aminotransferase, and creatine kinase activities, and blood urea nitrogen), and creatinine, all corrected for plasma volume changes. Urines were profiled for amino acid concentrations, normalized on creatinine excretion. Renal function, in terms of glomerular filtration rate, was monitored by MDRD equation corrected on body surface area. Creatine kinase activity and blood urea were increased during the race as did serum creatinine while kidney function remained stable. Among the amino acids, taurine, glycine, cysteine, leucine, carnosine, 1-methyl histidine, and 3-methyl histidine showed a net decreased, while homocysteine was increased. Taurine and the dipeptide carnosine (β-alanyl-L-histidine) were significantly correlated with the muscle activity markers and the indices of effort. In conclusion, the metabolic profile is modified strikingly due to the effort. Urinary taurine and carnosine seem useful tools to evaluate the muscle damage and possibly the fatigue status on a long-term basis.

  15. The Ciona intestinalis cleavage clock is independent of DNA methylation.

    PubMed

    Suzuki, Miho M; Mori, Tomoko; Satoh, Noriyuki

    2016-10-01

    The initiation of embryonic gene expression in ascidian embryos appears to be tightly regulated by the number of DNA replication cycles. DNA methylation is thought to contribute to the clock mechanism that counts the rounds of DNA replication. We used mass spectrometry and whole genome bisulfite sequencing to characterize DNA methylation changes that occur in early developmental stages of the ascidian, Ciona intestinalis. We found that global DNA methylation in early Ciona development was static, and a base-wise comparison between the genomes of consecutive developmental stages found no DNA demethylation that was related to zygotic gene activation. Additionally, 5hmC was hardly detected by mass spectrometry in the developmental samples, suggesting a lack of demethylation mediated by ten eleven translocation (TET) methylcytosine dioxygenase in C. intestinalis. We conclude that DNA methylation is not involved in regulating DNA replication-dependent transcriptional activation.

  16. Induction of heat shock protein 72 in C6 glioma cells by methyl jasmonate through ROS-dependent heat shock factor 1 activation.

    PubMed

    Oh, Su Young; Kim, Ji Hye; Park, Min Jung; Kim, Sun Mi; Yoon, Chang Shin; Joo, Young Mi; Park, Jang Su; Han, Song Iy; Park, Hye Gyeong; Kang, Ho Sung

    2005-11-01

    Salicylate and jasmonates are two different types of plant hormone that play critical roles in plant defense responses against insect herbivores and microbial pathogens, through activating defense genes. These two natural products have been shown to have similar activities in animal cells: the compounds are able to induce cell cycle arrest or apoptosis in a variety of human cancer cells including those of colon, prostate, breast, and leukemia, suggesting the chemicals may potentially be a novel class of anti-cancer drugs. Since sodium salicylate can induce the heat shock response in animals, we examined the effects of jasmonates on the heat shock response in C6 glioma cells. Here, we show that brief exposure to methyl jasmonate (MeJA), but not to jasmonic acid, induces heat shock protein 72 (HSP72), but not HSP73 and HSP90, via heat shock factor I (HSF1) activation in C6 glioma cells without affecting cell viability. Intracellular H2O2 and O2-, and mitochondrial ROS were prominently increased in response to 5 mM MeJA in C6 cells. MeJA-induced HSP72 expression, HSF1 DNA binding, and human HSP70 promoter-driven CAT activity were prevented by N-acetyl-L-cysteine (a general antioxidant), catalase (a specific antioxidant for H2O2), and sodium formate (an inhibitor of OH.), but not by Rac1 dominant negative mutant Rac1N17 and diphenyleneiodonium (a NADPH oxidase inhibitor), indicating that MeJA induces HSP72 expression though HSF1 that is activated via Rac1-NADPH oxidase-independent ROS production pathway. These results suggest that the plant stress hormones share the ability to induce heat shock response in animal cells.

  17. Ubiquitin vinyl methyl ester binding orients the misaligned active site of the ubiquitin hydrolase UCHL1 into productive conformation

    SciTech Connect

    Boudreaux, David A.; Maiti, Tushar K.; Davies, Christopher W.; Das, Chittaranjan

    2010-07-06

    Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) is a Parkinson disease-associated, putative cysteine protease found abundantly and selectively expressed in neurons. The crystal structure of apo UCHL1 showed that the active-site residues are not aligned in a canonical form, with the nucleophilic cysteine being 7.7 {angstrom} from the general base histidine, an arrangement consistent with an inactive form of the enzyme. Here we report the crystal structures of the wild type and two Parkinson disease-associated variants of the enzyme, S18Y and I93M, bound to a ubiquitin-based suicide substrate, ubiquitin vinyl methyl ester. These structures reveal that ubiquitin vinyl methyl ester binds primarily at two sites on the enzyme, with its carboxy terminus at the active site and with its amino-terminal {beta}-hairpin at the distal site - a surface-exposed hydrophobic crevice 17 {angstrom} away from the active site. Binding at the distal site initiates a cascade of side-chain movements in the enzyme that starts at a highly conserved, surface-exposed phenylalanine and is relayed to the active site resulting in the reorientation and proximal placement of the general base within 4 {angstrom} of the catalytic cysteine, an arrangement found in productive cysteine proteases. Mutation of the distal-site, surface-exposed phenylalanine to alanine reduces ubiquitin binding and severely impairs the catalytic activity of the enzyme. These results suggest that the activity of UCHL1 may be regulated by its own substrate.

  18. Occurrence rate of SAR arcs during the 23nd solar activity cycle

    NASA Astrophysics Data System (ADS)

    Ievenko, Igor

    By data of photometric observations at the Maimaga station (57° N, 200° E, geomagnetic coordinates) at the Yakutsk meridian the occurrence rate of subauroral red (SAR) arcs for the 1997 to 2006 period has been analysed. The observations were carried out during winterspring periods at moonless nights under favorable atmospheric conditions. For˜370 nights of observations (total duration is˜3170 hours) 114 cases of SAR arcs occurrence (˜500 hours) have been registered. The occurrence rate of SAR arcs have been determined as a ratio of the number of registration hour intervals of SAR arcs to the summary observation time in hours for particular months. Subauroral red arcs have been registered every year both in the maximum and in the minimum of the solar activity cycle. The most observation occurrence of red arcs is registered on the rise (˜27%) and decay of the maximum of the solar activity cycle (˜36%). The average occurrence rate of SAR arcs during these years was less than in the 22nd solar activity cycle and is equal to ˜16% of the total observation time. The occurrence rate of SAR arcs observations corresponds to the changes of geomagnetic activity during the 23nd solar activity cycle.

  19. Amygdala activation by corticosterone alters visceral and somatic pain in cycling female rats.

    PubMed

    Gustafsson, Jenny K; Greenwood-Van Meerveld, Beverley

    2011-06-01

    Irritable bowel syndrome (IBS) is often seen in women, and symptom severity is known to vary over the menstrual cycle. In addition, activation of the hypothalamic-pituitary-adrenal (HPA) axis enhances symptomology and patients with IBS have increased activation of the amygdala, a brain region known to facilitate HPA output. However, little is known about the effects of amygdala activation during different stages of the menstrual cycle. We therefore investigated the effects of amygdala activation on somatic and visceral pain perception over the rat estrous cycle. Female Wistar rats were implanted with either corticosterone (Cort) or cholesterol as a control onto the dorsal margin of the central amygdala. Visceral sensitivity was quantified by recording the visceromotor response (VMR) to colorectal distension (CRD) and somatic sensitivity was assessed via the Von Frey test. In cholesterol controls, both visceral and somatic sensitivity varied over the estrous cycle. Rats in proestrus/estrus responded to CRD with an increased VMR compared with rats in metestrus/diestrus. Somatic sensitivity followed a similar pattern with enhanced sensitivity during proestrus/estrus compared with metestrus/diestrus. Elevated amygdala Cort induced visceral hypersensitivity during metestrus/diestrus but had no effect during proestrus/estrus. In contrast, elevated amygdala Cort increased somatic sensitivity during both metestrus/diestrus and proestrus/estrous. These results suggests that amygdala activation by Cort eliminates spontaneously occurring differences in visceral and somatic pain perception, which could explain the lowered pain thresholds and higher incidence of somatic pain observed in women with IBS.

  20. SOLAR MAGNETIC ACTIVITY CYCLES, CORONAL POTENTIAL FIELD MODELS AND ERUPTION RATES

    SciTech Connect

    Petrie, G. J. D.

    2013-05-10

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the National Solar Observatory's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun vector spectro-magnetograph, the spectro-magnetograph and the 512-channel magnetograph instruments, and from Stanford University's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Polar field changes are found to be well correlated with active fields over most of the period studied, except between 2003 and 2006 when the active fields did not produce significant polar field changes. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The tilt of the solar dipole is therefore almost entirely due to active-region fields. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking, Solar Eruptive Event Detection System, and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003 and 2012 than for those between 1997 and 2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  1. The use of actimetry to assess changes to the rest-activity cycle.

    PubMed

    Carvalho Bos, Sandra; Waterhouse, Jim; Edwards, Ben; Simons, Ries; Reilly, Thomas

    2003-11-01

    The endogenous circadian oscillator (the body clock) is slow to adjust to altered rest-activity patterns. As a result, several negative consequences arise during night work and after time-zone transitions. The process of adjustment can be assessed by measurements of the sleep electroencephalogram (EEG), core temperature or melatonin secretion, for example, but these techniques are very difficult to apply in field studies, and make very great demands upon both experimenters and subjects. We have sought to establish if the activity record, measured conveniently and unobtrusively by a monitor attached to the wrist, can be treated in ways that enable estimates to be made of the disruption caused by changes to the rest-activity cycle, and the process of adjustment to them. In Part A, we describe the calculation and assessment of a series of "activity indices" that measure the overall activity pattern, activity when out of bed or in bed, or the activity in the hours adjacent to going to bed or getting up. The value of the indices was assessed by measuring changes to them in subjects undergoing night work or undergoing time-zone transitions. In both cases, there is a large body of literature describing the changes that would be expected. First, night workers (working 2 to 4 successive night shifts) were investigated during rest days and night shifts. The indices indicated that night work was associated with lower activity when the subjects were out of bed and higher activity when in bed. Some indices also measured when subjects took an afternoon nap before starting a series of night shifts and gave information about the process of adjustment to night work and recovery from it. Second, in studies from travelers crossing six or more time zones to the east or west, the indices indicated that there were changes to the rest-activity cycle immediately after the flights, both in its overall profile and when activity of the subjects in bed or out of bed was considered, and that

  2. Methylation matters

    PubMed Central

    Costello, J.; Plass, C.

    2001-01-01

    DNA methylation is not just for basic scientists any more. There is a growing awareness in the medical field that having the correct pattern of genomic methylation is essential for healthy cells and organs. If methylation patterns are not properly established or maintained, disorders as diverse as mental retardation, immune deficiency, and sporadic or inherited cancers may follow. Through inappropriate silencing of growth regulating genes and simultaneous destabilisation of whole chromosomes, methylation defects help create a chaotic state from which cancer cells evolve. Methylation defects are present in cells before the onset of obvious malignancy and therefore cannot be explained simply as a consequence of a deregulated cancer cell. Researchers are now able to detect with exquisite sensitivity the cells harbouring methylation defects, sometimes months or years before the time when cancer is clinically detectable. Furthermore, aberrant methylation of specific genes has been directly linked with the tumour response to chemotherapy and patient survival. Advances in our ability to observe the methylation status of the entire cancer cell genome have led us to the unmistakable conclusion that methylation abnormalities are far more prevalent than expected. This methylomics approach permits the integration of an ever growing repertoire of methylation defects with the genetic alterations catalogued from tumours over the past two decades. Here we discuss the current knowledge of DNA methylation in normal cells and disease states, and how this relates directly to our current understanding of the mechanisms by which tumours arise.


Keywords: methylation; cancer PMID:11333864

  3. Effects of exposure of DNA to methyl mercury on its activity as a template-primer for DNA polymerases.

    PubMed

    Frenkel, G D; Wilson, H; Ducote, J

    1986-06-01

    A previous publication [Frenkel, Cain, and Chao, Biochem. Biophys. Res. Commun. 127, 849-856 (1985)] described the observation that double-stranded DNA which was briefly exposed to methyl mercury (MeHg) and purified to remove free methyl mercury was transcribed at a higher rate by RNA polymerase II from wheat germ. The specificity of this phenomenon has now been investigated by examining the activity of this MeHg-exposed DNA as a template-primer for DNA polymerases. DNA synthesis by the bacteriophage T4-induced DNA polymerase was higher with the MeHg-exposed DNA as a template-primer than with control DNA. In contrast, the rate of DNA synthesis by E. coli DNA polymerase I was lower with the MeHg-exposed DNA as template-primer. With both enzymes (as well as with RNA polymerase II), after denaturation of the MeHg-exposed and control DNAs the differences in template activity were either eliminated or markedly reduced. The enzymes are thus able to detect a MeHg-induced alteration in DNA. In contrast, circular dichroism, a physical method that is sensitive to conformational changes in DNA, did not detect any difference between the MeHg-exposed and control DNAs.

  4. Antinociceptive activity of Paederosidic Acid Methyl Ester (PAME) from the n-butanol fraction of Paederia scandens in mice.

    PubMed

    Chen, Yu-Feng; Huang, Ying; Tang, Wei-Zhong; Qin, Lu-Ping; Zheng, Han-chen

    2009-08-01

    Antinociceptive activity of Paederosidic Acid Methyl Ester (PAME), a chemical compound isolated from the n-butanol fraction of Paederia scandens, was evaluated in mice using chemical and thermal models of nociception. PAME given by intraperitoneal injection at doses of 20, 40 and 60 mg/kg produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid, subplantar formalin or capsaicin injections and on thermal nociception in the tail-flick test and the hot plate test. In the pentobarbital sodium-induced sleep time test and the open-field test, PAME neither significantly enhanced the pentobarbital sodium-induced sleep time nor impaired the motor performance, indicating that the observed antinociceptive activity of PAME was unlikely due to sedation or motor abnormality. Core body temperature measurement showed that PAME did not affect temperature within a 2-h period. Moreover, PAME-induced antinociception in the hot plate test was insensitive to naloxone or nimodipine but significantly antagonized by L-NAME (N (G)-nitro-L-arginine methyl ester), methylene blue and glibenclamide. These results suggested that PAME-produced antinociception was possibly related to the pathway of NO-cGMP-ATP sensitive K(+) channels, which merited further studies regarding the precise site and mechanisms of action.

  5. A new solar signal: Average maximum sunspot magnetic fields independent of activity cycle

    NASA Astrophysics Data System (ADS)

    Livingston, William; Watson, Fraser

    2015-11-01

    Over the past 5 years, 2010 to April 2015, we observed 4176 sunspot umbrae in the infrared (IR) to measure maximum magnetic field strengths from the Zeeman splitting of Fe 15,648.5 Å. Herein we distinguish "field strengths" from "field flux." Field strengths range from 1500 G in pores to 3500+ in large spots. We made one observation per spot per observing day, ignoring spot size. We show that in the IR no activity cycle dependence on average maximum field strength (2070 ± 20 G) has been found. A similar analysis of 17,450 spots observed in space by the Helioseismic and Magnetic Imager reveals a similar cycle independence (2050 ± 0.18 G). We conclude that the average maximum umbral fields are constant with time and independent of the activity cycle within our time coverage.

  6. In vitro biological activity of aromadendrin-4'-methyl ether isolated from root extract of Ventilago madraspatana Gaertn with relevance to anticandidal activity.

    PubMed

    Rajesh, P S; Samaga, Pradeepa V; Rai, V Ravishankar; Rai, K M Lokanatha

    2015-01-01

    In this study, antimicrobial and antioxidant activities of the hexane extract of the root of Ventilago madraspatana were evaluated. Based on the significant bioactivity of crude hexane extract, an active compound was purified from the root extract. The active compound was further purified and identified as aromodendrin-4'-methyl ether by the (1)H NMR spectrum. The isolated compound significantly inhibited Staphylococcus epidermidis with the lowest MIC and MBC at 78 μg/mL (P < 0.05). The compound also exhibited significant anticandidal activity with MIC and MBC values of 312 and 625 μg/mL, respectively. The radical scavenging activity of aromodendrin-4'-methyl ether was evident by its lower IC50 values of 60 μg/mL for DPPH scavenging and 3.2 μg/mL for ABTS scavenging. The compound also exhibited ferrous ion chelation and H2O2 scavenging activities. The study is an attempt to increase the industrial utility of V. madrasapatana.

  7. Development of an Activated Carbon-Based Electrode for the Capture and Rapid Electrolytic Reductive Debromination of Methyl Bromide from Postharvest Fumigations.

    PubMed

    Li, Yuanqing; Liu, Chong; Cui, Yi; Walse, Spencer S; Olver, Ryan; Zilberman, David; Mitch, William A

    2016-10-18

    Due to concerns surrounding its ozone depletion potential, there is a need for technologies to capture and destroy methyl bromide (CH3Br) emissions from postharvest fumigations applied to control agricultural pests. Previously, we described a system in which CH3Br fumes vented from fumigation chambers could be captured by granular activated carbon (GAC). The GAC was converted to a cathode by submergence in a high ionic strength solution and connection to the electrical grid, resulting in reductive debromination of the sorbed CH3Br. The GAC bed was drained and dried for reuse to capture and destroy CH3Br fumes from the next fumigation. However, the loose GAC particles and slow kinetics of this primitive electrode necessitated improvements. Here, we report the development of a cathode containing a thin layer of small GAC particles coating carbon cloth as a current distributor. Combining the high sorption potential of GAC for CH3Br with the conductivity of the carbon cloth current distributor, the cathode significantly lowered the total cell resistance and achieved 96% reductive debromination of CH3Br sorbed at 30% by weight to the GAC within 15 h at -1 V applied potential vs standard hydrogen electrode, a time scale and efficiency suitable for postharvest fumigations. The cathode exhibited stable performance over 50 CH3Br capture and destruction cycles. Initial cost estimates indicate that this technique could treat CH3Br fumes at ∼$5/kg, roughly one-third of the cost of current alternatives.

  8. The Development of a New Practical Activity: Using Microorganisms to Model Gas Cycling

    ERIC Educational Resources Information Center

    Redfern, James; Burdass, Dariel; Verran, Joanna

    2014-01-01

    For many in the school science classroom, the term "microbiology" has become synonymous with "bacteriology". By overlooking other microbes, teachers may miss out on powerful practical tools. This article describes the development of an activity that uses algae and yeast to demonstrate gas cycling, and presents full instructions…

  9. US Activities in Making Life Cycle Inventory Data More Available to Users

    EPA Science Inventory

    The demand for LCA studies continues to grow, although, the lack of reliable, transparent Life Cycle Inventory (LCI) data is hampering the wide-spread application of LCA. This paper will present activities related to the development and accessibility of process LCI data in the U...

  10. Geomagnetic activity during 10 - 11 solar cycles that has been observed by old Russian observatories.

    NASA Astrophysics Data System (ADS)

    Seredyn, Tomasz; Wysokinski, Arkadiusz; Kobylinski, Zbigniew; Bialy, Jerzy

    2016-07-01

    A good knowledge of solar-terrestrial relations during past solar activity cycles could give the appropriate tools for a correct space weather forecast. The paper focuses on the analysis of the historical collections of the ground based magnetic observations and their operational indices from the period of two sunspot solar cycles 10 - 11, period 1856 - 1878 (Bartels rotations 324 - 635). We use hourly observations of H and D geomagnetic field components registered at Russian stations: St. Petersburg - Pavlovsk, Barnaul, Ekaterinburg, Nertshinsk, Sitka, and compare them to the data obtained from the Helsinki observatory. We compare directly these records and also calculated from the data of the every above mentioned station IHV indices introduced by Svalgaard (2003), which have been used for further comparisons in epochs of assumed different polarity of the heliospheric magnetic field. We used also local index C9 derived by Zosimovich (1981) from St. Petersburg - Pavlovsk data. Solar activity is represented by sunspot numbers. The correlative and continuous wavelet analyses are applied for estimation of the correctness of records from different magnetic stations. We have specially regard to magnetic storms in the investigated period and the special Carrington event of 1-2 Sep 1859. Generally studied magnetic time series correctly show variability of the geomagnetic activity. Geomagnetic activity presents some delay in relation to solar one as it is seen especially during descending and minimum phase of the even 11-year cycle. This pattern looks similarly in the case of 16 - 17 solar cycles.

  11. Soybean (Glycine max. L.) and bacteroid glyoxylate cycle activities during nodular senescence.

    PubMed

    Fargeix, Christophe; Gindro, Katia; Widmer, François

    2004-02-01

    Soybean (Glycine max. L.) nodular senescence results in the dismantling of the peribacteroid membrane (PBM) and in an increase of soybean isocitrate lyase (ICL; EC 4.1.3.1) and malate synthase (MS; EC 4.1.3.2) mRNA and protein levels. This suggests that in senescing soybean nodular cells, the specific glyoxylate cycle enzyme activities might be induced to reallocate carbon obtained from the PBM degradation. In order to evaluate as well the carbon metabolism of the nitrogen-fixing Bradyrhizobium japonicum endosymbiotic bacteroids during nodular senescence, their glyoxylate cycle activities were also investigated. To this end, partial DNA sequences were isolated from their icl and ms genes, but the corresponding mRNAs were not detected in the microorganisms. It was also observed that the bacteroid ICL and MS activities were negligible during nodular senescence. This suggests that glyoxylate cycle activities are not reinitiated in the bacteroids under these physiological conditions. In case the microorganisms nevertheless feed on the PBM degradation products, this might occur via the citric acid cycle exclusively.

  12. A schizophrenic patient with an arrhythmic circadian rest-activity cycle.

    PubMed

    Wirz-Justice, A; Cajochen, C; Nussbaum, P

    1997-11-14

    A haloperidol-treated patient with chronic schizophrenia had a near-arrhythmic circadian rest-activity cycle, whereas rhythms of 6-sulphatoxy-melatonin and core body temperature were of normal amplitude and phase-advanced. Sleep electroencephalography measured throughout a 31-h 'constant-bedrest' protocol revealed a phase-delayed sleep-wake propensity cycle, low sleep continuity (ultradian 'bouts'), and very little slow-wave sleep and slow-wave activity (0.75-4.5 Hz). Switching treatment to the atypical neuroleptic clozapine improved both the circadian organization of the rest-activity cycle and the patient's clinical state. This observation can be conceptualized in terms of the two-process model of sleep regulation. High-dose haloperidol treatment may have lowered the circadian alertness threshold, whereas clozapine augmented circadian amplitude (perhaps through its high affinity to dopamine D4 and serotonin 5HT7 receptors in the suprachiasmatic nuclei). Measurement of the circadian rest-activity cycle may be a useful non-invasive method to follow functional consequences of neuroleptic treatment.

  13. H3 Lysine 4 Is Acetylated at Active Gene Promoters and Is Regulated by H3 Lysine 4 Methylation

    PubMed Central

    Guillemette, Benoit; Drogaris, Paul; Lin, Hsiu-Hsu Sophia; Armstrong, Harry; Hiragami-Hamada, Kyoko; Imhof, Axel; Bonneil, Éric; Thibault, Pierre; Verreault, Alain; Festenstein, Richard J.

    2011-01-01

    Methylation of histone H3 lysine 4 (H3K4me) is an evolutionarily conserved modification whose role in the regulation of gene expression has been extensively studied. In contrast, the function of H3K4 acetylation (H3K4ac) has received little attention because of a lack of tools to separate its function from that of H3K4me. Here we show that, in addition to being methylated, H3K4 is also acetylated in budding yeast. Genetic studies reveal that the histone acetyltransferases (HATs) Gcn5 and Rtt109 contribute to H3K4 acetylation in vivo. Whilst removal of H3K4ac from euchromatin mainly requires the histone deacetylase (HDAC) Hst1, Sir2 is needed for H3K4 deacetylation in heterochomatin. Using genome-wide chromatin immunoprecipitation (ChIP), we show that H3K4ac is enriched at promoters of actively transcribed genes and located just upstream of H3K4 tri-methylation (H3K4me3), a pattern that has been conserved in human cells. We find that the Set1-containing complex (COMPASS), which promotes H3K4me2 and -me3, also serves to limit the abundance of H3K4ac at gene promoters. In addition, we identify a group of genes that have high levels of H3K4ac in their promoters and are inadequately expressed in H3-K4R, but not in set1Δ mutant strains, suggesting that H3K4ac plays a positive role in transcription. Our results reveal a novel regulatory feature of promoter-proximal chromatin, involving mutually exclusive histone modifications of the same histone residue (H3K4ac and H3K4me). PMID:21483810

  14. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity

    PubMed Central

    Patterson, Rainey E.; Kalavalapalli, Srilaxmi; Williams, Caroline M.; Nautiyal, Manisha; Mathew, Justin T.; Martinez, Janie; Reinhard, Mary K.; McDougall, Danielle J.; Rocca, James R.; Yost, Richard A.; Cusi, Kenneth; Garrett, Timothy J.

    2016-01-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by 13C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P < 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of “lipotoxic” metabolites in the liver and could hasten inflammation and the metabolic transition to NASH. PMID:26814015

  15. Lipotoxicity in steatohepatitis occurs despite an increase in tricarboxylic acid cycle activity.

    PubMed

    Patterson, Rainey E; Kalavalapalli, Srilaxmi; Williams, Caroline M; Nautiyal, Manisha; Mathew, Justin T; Martinez, Janie; Reinhard, Mary K; McDougall, Danielle J; Rocca, James R; Yost, Richard A; Cusi, Kenneth; Garrett, Timothy J; Sunny, Nishanth E

    2016-04-01

    The hepatic tricarboxylic acid (TCA) cycle is central to integrating macronutrient metabolism and is closely coupled to cellular respiration, free radical generation, and inflammation. Oxidative flux through the TCA cycle is induced during hepatic insulin resistance, in mice and humans with simple steatosis, reflecting early compensatory remodeling of mitochondrial energetics. We hypothesized that progressive severity of hepatic insulin resistance and the onset of nonalcoholic steatohepatitis (NASH) would impair oxidative flux through the hepatic TCA cycle. Mice (C57/BL6) were fed a high-trans-fat high-fructose diet (TFD) for 8 wk to induce simple steatosis and NASH by 24 wk. In vivo fasting hepatic mitochondrial fluxes were determined by(13)C-nuclear magnetic resonance (NMR)-based isotopomer analysis. Hepatic metabolic intermediates were quantified using mass spectrometry-based targeted metabolomics. Hepatic triglyceride accumulation and insulin resistance preceded alterations in mitochondrial metabolism, since TCA cycle fluxes remained normal during simple steatosis. However, mice with NASH had a twofold induction (P< 0.05) of mitochondrial fluxes (μmol/min) through the TCA cycle (2.6 ± 0.5 vs. 5.4 ± 0.6), anaplerosis (9.1 ± 1.2 vs. 16.9 ± 2.2), and pyruvate cycling (4.9 ± 1.0 vs. 11.1 ± 1.9) compared with their age-matched controls. Induction of the TCA cycle activity during NASH was concurrent with blunted ketogenesis and accumulation of hepatic diacylglycerols (DAGs), ceramides (Cer), and long-chain acylcarnitines, suggesting inefficient oxidation and disposal of excess free fatty acids (FFA). Sustained induction of mitochondrial TCA cycle failed to prevent accretion of "lipotoxic" metabolites in the liver and could hasten inflammation and the metabolic transition to NASH.

  16. Procyclic Trypanosoma brucei do not use Krebs cycle activity for energy generation.

    PubMed

    van Weelden, Susanne W H; Fast, Beate; Vogt, Achim; van der Meer, Pieter; Saas, Joachim; van Hellemond, Jaap J; Tielens, Aloysius G M; Boshart, Michael

    2003-04-11

    The importance of a functional Krebs cycle for energy generation in the procyclic stage of Trypanosoma brucei was investigated under physiological conditions during logarithmic phase growth of a pleomorphic parasite strain. Wild type procyclic cells and mutants with targeted deletion of the gene coding for aconitase were derived by synchronous in vitro differentiation from wild type and mutant (Delta aco::NEO/Delta aco::HYG) bloodstream stage parasites, respectively, where aconitase is not expressed and is dispensable. No differences in intracellular levels of glycolytic and Krebs cycle intermediates were found in procyclic wild type and mutant cells, except for citrate that accumulated up to 90-fold in the mutants, confirming the absence of aconitase activity. Surprisingly, deletion of aconitase did not change differentiation nor the growth rate or the intracellular ATP/ADP ratio in those cells. Metabolic studies using radioactively labeled substrates and NMR analysis demonstrated that glucose and proline were not degraded via the Krebs cycle to CO(2). Instead, glucose was degraded to acetate, succinate, and alanine, whereas proline was degraded to succinate. Importantly, there was absolutely no difference in the metabolic products released by wild type and aconitase knockout parasites, and both were for survival strictly dependent on respiration via the mitochondrial electron transport chain. Hence, although the Krebs cycle enzymes are present, procyclic T. brucei do not use Krebs cycle activity for energy generation, but the mitochondrial respiratory chain is essential for survival and growth. We therefore propose a revised model of the energy metabolism of procyclic T. brucei.

  17. Limit cycle analysis of active disturbance rejection control system with two nonlinearities.

    PubMed

    Wu, Dan; Chen, Ken

    2014-07-01

    Introduction of nonlinearities to active disturbance rejection control algorithm might have high control efficiency in some situations, but makes the systems with complex nonlinearity. Limit cycle is a typical phenomenon that can be observed in the nonlinear systems, usually causing failure or danger of the systems. This paper approaches the problem of the existence of limit cycles of a second-order fast tool servo system using active disturbance rejection control algorithm with two fal nonlinearities. A frequency domain approach is presented by using describing function technique and transfer function representation to characterize the nonlinear system. The derivations of the describing functions for fal nonlinearities and treatment of two nonlinearities connected in series are given to facilitate the limit cycles analysis. The effects of the parameters of both the nonlinearity and the controller on the limit cycles are presented, indicating that the limit cycles caused by the nonlinearities can be easily suppressed if the parameters are chosen carefully. Simulations in the time domain are performed to assess the prediction accuracy based on the describing function.

  18. Relationship between the methylation status of dietary flavonoids and their growth-inhibitory and apoptosis-inducing activities in human cancer cells

    PubMed Central

    Landis-Piwowar, Kristin R.; Milacic, Vesna; Dou, Q. Ping

    2008-01-01

    Flavonoids are polyphenolic compounds widely distributed in the plant kingdom. Compelling research indicates that flavonoids have important roles in cancer chemoprevention and chemotherapy possibly due to biological activities that include action through anti-inflammation, free radical scavenging, modulation of survival/proliferation pathways, and inhibition of the ubiquitin-proteasome pathway. Plant polyphenols including the green tea polyphenol, (-)-epigallocatechin gallate or (-)-EGCG, and the flavonoids apigenin, luteolin, quercetin, and chrysin have been shown to inhibit proteasome activity and induce apoptosis in human leukemia cells. However, biotransformation reactions to the reactive hydroxyl groups on polyphenols could reduce their biological activities. Although methylated polyphenols have been suggested to be metabolically more stable than unmethylated polyphenols, the practical use of methylated polyphenols as a cancer preventative agent warrants further investigation. In the current study, methylated and unmethylated flavonoids were studied for their proteasome-inhibitory and apoptosis-inducing abilities in human leukemia HL60 cells. Methylated flavonoids displayed sustained bioavailability and inhibited cellular proliferation by arresting cells in the G1 phase. However, they did not act as proteasome inhibitors in either an in vitro system or an in silico model and only weakly induced apoptosis. In contrast, unmethylated flavonoids exhibited inhibition of the proteasomal activity in intact HL60 cells, accumulating proteasome target proteins and inducing caspase activation and poly (ADP-ribose) polymerase cleavage. We conclude that methylated flavonoids lack potent cytotoxicity against human leukemia cells and most likely have limited ability as chemopreventive agents. PMID:18636546

  19. Genome-wide analysis of DNA methylation and gene expression patterns in purified, uncultured human liver cells and activated hepatic stellate cells

    PubMed Central

    Reiner, Andrew H.; Coll, Mar; Verhulst, Stefaan; Mannaerts, Inge; Øie, Cristina I.; Smedsrød, Bård; Najimi, Mustapha; Sokal, Etienne; Luttun, Aernout; Sancho-Bru, Pau; Collas, Philippe; van Grunsven, Leo A.

    2015-01-01

    Background & Aims Liver fibrogenesis – scarring of the liver that can lead to cirrhosis and liver cancer – is characterized by hepatocyte impairment, capillarization of liver sinusoidal endothelial cells (LSECs) and hepatic stellate cell (HSC) activation. To date, the molecular determinants of a healthy human liver cell phenotype remain largely uncharacterized. Here, we assess the transcriptome and the genome-wide promoter methylome specific for purified, non-cultured human hepatocytes, LSECs and HSCs, and investigate the nature of epigenetic changes accompanying transcriptional changes associated with activation of HSCs. Material and methods Gene expression profile and promoter methylome of purified, uncultured human liver cells and culture-activated HSCs were respectively determined using Affymetrix HG-U219 genechips and by methylated DNA immunoprecipitation coupled to promoter array hybridization. Histone modification patterns were assessed at the single-gene level by chromatin immunoprecipitation and quantitative PCR. Results We unveil a DNA-methylation-based epigenetic relationship between hepatocytes, LSECs and HSCs despite their distinct ontogeny. We show that liver cell type-specific DNA methylation targets early developmental and differentiation-associated functions. Integrative analysis of promoter methylome and transcriptome reveals partial concordance between DNA methylation and transcriptional changes associated with human HSC activation. Further, we identify concordant histone methylation and acetylation changes in the promoter and putative novel enhancer elements of genes involved in liver fibrosis. Conclusions Our study provides the first epigenetic blueprint of three distinct freshly isolated, human hepatic cell types and of epigenetic changes elicited upon HSC activation. PMID:26353929

  20. Solar activity cycle and the incidence of foetal chromosome abnormalities detected at prenatal diagnosis

    NASA Astrophysics Data System (ADS)

    Halpern, Gabrielle J.; Stoupel, Eliahu G.; Barkai, Gad; Chaki, Rina; Legum, Cyril; Fejgin, Moshe D.; Shohat, Mordechai

    1995-06-01

    We studied 2001 foetuses during the period of minimal solar activity of solar cycle 21 and 2265 foetuses during the period of maximal solar activity of solar cycle 22, in all women aged 37 years and over who underwent free prenatal diagnosis in four hospitals in the greater Tel Aviv area. There were no significant differences in the total incidence of chromosomal abnormalities or of trisomy between the two periods (2.15% and 1.8% versus 2.34% and 2.12%, respectively). However, the trend of excessive incidence of chromosomal abnormalities in the period of maximal solar activity suggests that a prospective study in a large population would be required to rule out any possible effect of extreme solar activity.

  1. Structure revision and cytotoxic activity of marinamide and its methyl ester, novel alkaloids produced by co-cultures of two marine-derived mangrove endophytic fungi.

    PubMed

    Zhu, Feng; Chen, Guangying; Wu, Jingshu; Pan, Jiahui

    2013-01-01

    Marinamide (1) and its methyl ester (2) have been previously reported as pyrrolyl 1-isoquinolone alkaloids, which were produced by co-cultures of two marine-derived mangrove endophytic fungi from the South China Sea coast. Recrystallisation of methyl marinamide (2) from pyridine forms the known pesticide, quinolactacide (3). Treatment of 3 with methyl iodide to afford N-methyl quinolactacide (4) was identified by X-ray crystallography. Thus, the structures of 1 and 2 were revised from the previously reported pyrrolyl 1-isoquinolone structures to pyrrolyl 4-quinolone analogues. In the MTT assays, both 1 and 2 exhibited potent cytotoxic activity against HepG2, 95-D, MGC832 and HeLa tumour cell lines.

  2. Microbial activities and phosphorus cycling: An application of oxygen isotope ratios in phosphate

    NASA Astrophysics Data System (ADS)

    Stout, Lisa M.; Joshi, Sunendra R.; Kana, Todd M.; Jaisi, Deb P.

    2014-08-01

    Microorganisms carry out biochemical transformations of nutrients that make up their cells. Therefore, understanding how these nutrients are transformed or cycled in natural environments requires knowledge of microbial activity. Commonly used indicators for microbial activity typically include determining microbial respiration by O2/CO2 measurements, cell counts, and measurement of enzyme activities. However, coupled studies on nutrient cycling and microbial activity are not given enough emphasis. Here we apply phosphate oxygen isotope ratios (δ18OP) as a tool for measurement of microbial activity and compare the rate of isotope exchange with methods of measuring microbial activities that are more commonly applied in environmental studies including respiration, dehydrogenase activity, alkaline phosphatase activity, and cell counts. Our results show that different bacteria may have different strategies for P uptake, storage and release, their respiration and consequently expression of DHA and APase activities, but in general the trend of their enzyme activities are comparable. Phosphate δ18OP values correlated well with these other parameters used to measure microbial activity with the strongest linear relationships between δ18OP and CO2 evolution (r = -0.99). Even though the rate of isotope exchange for each microorganism used in this study is different, the rate per unit CO2 respiration showed one general trend, where δ18OP values move towards equilibrium while CO2 is generated. While this suggests that P cycling among microorganisms used in this study can be generalized, further research is needed to determine whether the microorganism-specific isotope exchange trend may occur in natural environments. In summary, phosphate oxygen isotope measurements may offer an alternative for use as a tracer to measure microbial activity in soils, sediments, and many other natural environments.

  3. Molecular mechanisms underlying activity-dependent AMPA receptor cycling in retinal ganglion cells

    PubMed Central

    Casimiro, Tanya M.; Nawy, Scott; Carroll, Reed C.

    2013-01-01

    On retinal ganglion cells (RGCs) transmit light encoded information to the brain and receive excitatory input from On cone bipolar cells (CBPs). The synaptic CBP input onto On RGCs is mediated by AMPA-type glutamate receptors (AMPARs) that include both those lacking a GluA2 subunit, and are therefore permeable to Ca2+, and those that possess at least one GluA2 subunit and are Ca2+-impermeable. We have previously demonstrated in electrophysiological studies that periods of low synaptic activity, brought about by housing animals in darkness, enhances the proportion of GluA2-lacking AMPARs at the On CBP-On RGC synapse by mobilizing surface GluA2 containing receptors into a receptor pool that rapidly cycles in and out of the membrane. AMPAR cycling induction by reduced synaptic activity takes several hours. This delay suggests that changes in expression of proteins which regulate AMPAR trafficking may mediate the altered mobility of GluA2 AMPARs in RGCs. In this study, we test the hypothesis that AMPAR trafficking proteins couple synaptic activity to AMPAR cycling in RGCs. Immunocytochemical and biochemical analysis confirmed that darkness decreases surface GluA2 in RGCs and changed the expression levels of three proteins associated with GluA2 trafficking. GRIP was decreased, while PICK1 and Arc were increased. Knockdown of GRIP with siRNA elevated constitutive AMPAR cycling, mimicking effects of reduced synaptic activity, while knockdown of PICK1 and ARC blocked increases in constitutive GluA2 trafficking. Our results support a role for correlated, activity-driven changes in multiple AMPAR trafficking proteins that modulate GluA2 cycling which can in turn affect synaptic AMPAR composition in RGCs. PMID:23911793

  4. Male prairie voles display cardiovascular dipping associated with an ultradian activity cycle.

    PubMed

    Lewis, Robert; Curtis, J Thomas

    2016-03-15

    Mammals typically display alternating active and resting phases and, in most species, these rhythms follow a circadian pattern. The active and resting phases often are accompanied by corresponding physiological changes. In humans, blood pressure decreases during the resting phase of the activity cycle, and the magnitude of that "nocturnal dipping" has been used to stratify patients according to the risk for cardiovascular disease. However, in contrast to most mammals, prairie voles (Microtus ochrogaster) have periods of activity and rest that follow an ultradian rhythm with period lengths significantly <24h. While rhythmic changes in blood pressure across a circadian activity cycle have been well-documented, blood pressure patterns in species that display ultradian rhythms in activity are less well-studied. In the current study, we implanted pressure-sensitive radiotelemetry devices in male prairie voles and recorded activity, mean arterial pressure (MAP), and heart rate (HR) continuously for 3days. Visualization of the ultradian rhythms was enhanced using a 1h running average to filter the dataset. Positive correlations were found between activity and MAP and between activity and HR. During the inactive period of the ultradian cycle, blood pressure decreased by about 15%, which parallels the nocturnal dipping pattern seen in healthy humans. Further, the duration of inactivity did not affect any of the cardiovascular measures, so the differences in blood pressure values between the active and inactive periods are likely driven by ultradian oscillations in hormones and autonomic function. Finally, specific behavioral patterns also were examined. Both the instrumented animal and his non-instrumented cagemate appeared to show synchronized activity patterns, with both animals displaying sleep-like behavior for more than 90% of the inactive period. We propose that the prairie vole ultradian rhythm in blood pressure is an analogue for circadian blood pressure variability

  5. Reactivity and regioselectivity in reactions of methyl and ethyl azides with cyclooctynes: activation strain model and energy decomposition analysis.

    PubMed

    de S Vilhena, Felipe; de M Carneiro, José Walkimar

    2017-01-01

    The structures and energies for the Huisgen 1,3-dipolar cycloaddition reactions of methyl and ethyl azides with some cyclooctynes and dibenzocyclooctynes were computed at the B3LYP/6-311++G(d,p) level. The activation strain model (ASM) and quantitative molecular orbital (MO) theory were used to investigate the reactivity and regiochemistry in these reactions. The energy decomposition analysis (EDA) was used to identify the intrinsic electronic factor that lead to the preferential formation of 1,7-regiochemistry products. The reactivity order agrees with formation of more synchronous transition states and lower distortion energies. For the reaction of N3Met with azacyclooctyne, the 1,7-regiochemistry preference is attributed to a lower FMO gap and a higher contribution of the polarization term of the interaction energy than for the 1,8-transition state. For the reaction with aza-dibenzocyclooctyne, the 1,7-preference is due to a lower strain energy and a more pronounced contribution of the exchange term of the interaction energy. Graphical Abstract In the reactions between methyl and ethyl azides with azacyclooctynes the regiochemistry is governed by the intrinsic electronic factors.

  6. The effect of cycling on muscle activation in the running leg of an Olympic distance triathlon.

    PubMed

    Heiden, Tamika; Burnett, Angus

    2003-01-01

    The aim of this study was to determine the effect of prior cycling on EMG activity of selected lower leg muscles during running. Ten elite level triathletes underwent two testing sessions at race pace: a 40 km cycle followed by a 2 km run (CR) and a 10 km run followed by a 2 km run (RR). EMG data from selected lower limb muscles were collected at three sections of each run (0 km, 1 km and 2 km) for six strides using a portable data logger. Significant differences (p < 0.05) between condition were found for the level of activation (Lact) for biceps femoris (BF) during stance and vastus lateralis (VL) during flight and stance. Vastus medialis (VM) changed in Lact, during flight, between sections in the 2 km run. Furthermore, significant differences (p < 0.05) between condition were found for BF during stance and for rectus femoris (RF) and VM during flight. There was a significant difference (p < 0.05) in the duration of VL activation (Dact) across sections of the 2 km run. Findings from this investigation highlight changes in muscle function when changing from cycling to running and indicate a need to train specifically for the cycle to run transition. Such training may improve performance and reduce the risk of injury.

  7. Stellar activity cycles from long-term data by robotic telescopes

    NASA Astrophysics Data System (ADS)

    Oláh, K.

    2014-03-01

    All results about stellar activity cycles stem from decades-long systematic observations that were done by small telescopes. Without these equipments we would not know much, if anything, about stellar activity cycles, like those we see and observe easily on the nearest star, the Sun. In the early 80's of the last century systematic photometric monitoring of active stars began with automated photometric telescopes (APTs), some of which continue the observations to date. The Vienna-Potsdam APT now works for about two decades (Strassmeier et al. 1997), similarly to the 4-College Consortium APT (Dukes et al. 1995), while the Catania APT (Rodono et al. 2001) was closed down a few years ago. These small tools with the same setups for decades do not cost much and are relatively cheap to maintain. The longest continuous photometric datasets of a few objects from APTs span now over 30 years, which, together with earlier, manually-obtained data allow to study those activity cycles of stars which are in the order of 10 years or shorter: to be sure in the timescale of a cycle it should be observed repeatedly at least 2-3 times. The spectroscopic automated telescope STELLA (Strassmeier et al. 2004), built in the first decade of this century, measured already a few dozens of radial velocity curves for long-period binary stars and measured their activity levels (Strassmeier et al. 2012); these results can be gathered only by robotic telescopes. Only with STELLA it is possible to study the decades-long behavior of starspots on active giants with long rotational periods via Doppler Imaging. As the databases were growing it became clear that stars, just as the Sun, had multiple cycles. It was also found that stellar cycles showed systematic changes and that the cycle lengths correlated with the rotational periods of the stars. Extensive summaries of stellar activity cycles are found in Baliunas et al. (1995) using the Mt. Wilson Ca-index survey, and Oláh et al. (2009) based on

  8. Arginine methylation-dependent reader-writer interplay governs growth control by E2F-1.

    PubMed

    Zheng, Shunsheng; Moehlenbrink, Jutta; Lu, Yi-Chien; Zalmas, Lykourgos-Panagiotis; Sagum, Cari A; Carr, Simon; McGouran, Joanna F; Alexander, Leila; Fedorov, Oleg; Munro, Shonagh; Kessler, Benedikt; Bedford, Mark T; Yu, Qiang; La Thangue, Nicholas B

    2013-10-10

    The mechanisms that underlie and dictate the different biological outcomes of E2F-1 activity have yet to be elucidated. We describe the residue-specific methylation of E2F-1 by the asymmetric dimethylating protein arginine methyltransferase 1 (PRMT1) and symmetric dimethylating PRMT5 and relate the marks to different functional consequences of E2F-1 activity. Methylation by PRMT1 hinders methylation by PRMT5, which augments E2F-1-dependent apoptosis, whereas PRMT5-dependent methylation favors proliferation by antagonizing methylation by PRMT1. The ability of E2F-1 to prompt apoptosis in DNA damaged cells coincides with enhanced PRMT1 methylation. In contrast, cyclin A binding to E2F-1 impedes PRMT1 methylation and augments PRMT5 methylation, thus ensuring that E2F-1 is locked into its cell-cycle progression mode. The Tudor domain protein p100-TSN reads the symmetric methylation mark, and binding of p100-TSN downregulates E2F-1 apoptotic activity. Our results define an exquisite level of precision in the reader-writer interplay that governs the biological outcome of E2F-1 activity.

  9. Arginine methylation-dependent reader-writer interplay governs growth control by E2F-1

    PubMed Central

    Zheng, Shunsheng; Moehlenbrink, Jutta; Lu, Yi-Chien; Zalmas, Lykourgos-Panagiotis; Sagum, Cari A.; Carr, Simon; McGouran, Joanna F.; Alexander, Leila; Fedorov, Oleg; Munro, Shonagh; Kessler, Benedikt; Bedford, Mark T.; Yu, Qiang; La Thangue, Nicholas B.

    2014-01-01

    Summary The mechanisms that underlie and dictate the different biological outcomes of E2F-1 activity have yet to be elucidated. We describe the residue-specific methylation of E2F-1 by the asymmetric dimethylating protein arginine methyltransferase (PRMT) 1 and symmetric dimethylating PRMT5, and relate the marks to different functional consequences of E2F-1 activity. Methylation by PRMT1 hinders methylation by PRMT5, which augments E2F-1-dependent apoptosis, whereas PRMT5-dependent methylation favours proliferation by antagonising methylation by PRMT1. The ability of E2F-1 to prompt apoptosis in DNA damaged cells coincides with enhanced PRMT1 methylation. In contrast, cyclin A binding to E2F-1 impedes PRMT1 methylation and augments PRMT5 methylation, thus ensuring that E2F-1 is locked into its cell cycle progression mode. The Tudor domain protein p100-TSN reads the symmetric methylation mark, and binding of p100-TSN down-regulates E2F-1 apoptotic activity. Our results define an exquisite level of precision in the reader-writer interplay that governs the biological outcome of E2F-1 activity. PMID:24076217

  10. Impairment of N-methyl-D-aspartate receptor-controlled motor activity in LYN-deficient mice.

    PubMed

    Umemori, H; Ogura, H; Tozawa, N; Mikoshiba, K; Nishizumi, H; Yamamoto, T

    2003-01-01

    The N-methyl-D-aspartate (NMDA) receptor, an ionotropic glutamate receptor, is implicated in motor activity that is regulated in the striatum and nucleus accumbens of the brain. A Src family kinase Lyn is highly expressed in striatum, cortex, thalamus, and cerebellum in the brain. Here we show that spontaneous motor activity is suppressed in lyn-/- mice. S.c. injection of methylphenidate, which causes accumulation of dopamine in synapses, reveals that dopaminergic pathway is normal in lyn-/- mice. After blocking the NMDA receptor, motor activity of lyn-/- mice increased to the same level as that of wild type mice. Therefore, the NMDA receptor-mediated signaling is enhanced in lyn-/- mice, indicating that Lyn regulates the NMDA receptor pathway negatively. Intriguingly, the activity of protein kinase C (PKC), an enzyme regulated downstream of NMDA receptors, is increased in lyn-/- mice. The present data suggest that the NMDA receptor signal that is enhanced in the absence of Lyn suppresses the motor activity, probably through inhibition of dopaminergic pathway at striatum. We conclude that Lyn contributes to coordination of motor activity through regulation of the NMDA pathway. It appears that this negative regulation involves suppression of downstream signaling of NMDA receptor such as those mediated by PKC.

  11. Degradation of methyl orange by composite photocatalysts nano-TiO2 immobilized on activated carbons of different porosities.

    PubMed

    Wang, Xiaojing; Liu, Yafei; Hu, Zhonghua; Chen, Yujuan; Liu, Wei; Zhao, Guohua

    2009-09-30

    Composite photocatalysts TiO(2) immobilized on granular activated carbons with different porosities (TiO(2)/AC) were prepared by a novel approach, dip-hydrothermal method using peroxotitanate as precursor. The TiO(2)/AC composites were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and the nitrogen absorption. Their photocatalytic activity was evaluated by degradation of methyl orange (MO). The results showed that nano-TiO(2) particles of anatase type were well deposited on the activated carbon surface. The porosity of activated carbon had significant influence on the adsorption, the amount of TiO(2) deposited on the external surface of AC and the activity of composite photocatalysts. The composite TiO(2)/AC made from proper mesoporosity AC exhibited higher catalytic activity than the mixture of powdered TiO(2) with AC. Furthermore, the mechanism of synergistic effect of AC adsorption and TiO(2) photocatalysis was discussed.

  12. Solar magnetic activity cycles, coronal potential field models and eruption rates

    NASA Astrophysics Data System (ADS)

    Petrie, Gordon

    2013-07-01

    We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated potential-field models based on longitudinal full-disk photospheric magnetograms from the NSO's three magnetographs at Kitt Peak, the Synoptic Optical Long-term Investigations of the Sun (SOLIS) vector spectro-magnetograph (VSM), the spectro-magnetograph and the 512-channel magnetograph instruments, and from the U. Stanford's Wilcox Solar Observatory. The associated multipole field components are used to study the dominant length scales and symmetries of the coronal field. Of the axisymmetric multipoles, only the dipole and octupole follow the poles whereas the higher orders follow the activity cycle. All non-axisymmetric multipole strengths are well correlated with the activity cycle. The axial dipole and octupole are the largest contributors to the global field except while the polar fields are reversing. This influence of the polar fields extends to modulating eruption rates. According to the Computer Aided CME Tracking (CACTus), Solar Eruptive Event Detection System (SEEDS), and Nobeyama radioheliograph prominence eruption catalogs, the rate of solar eruptions is found to be systematically higher for active years between 2003-2012 than for those between 1997-2002. This behavior appears to be connected with the weakness of the late-cycle 23 polar fields as suggested by Luhmann. We see evidence that the process of cycle 24 field reversal is well advanced at both poles.

  13. Low cycle fatigue properties of a low activation ferritic steel (JLF-1) at room temperature

    NASA Astrophysics Data System (ADS)

    Nishimura, A.; Nagasaka, T.; Inoue, N.; Muroga, T.; Namba, C.

    2000-12-01

    To investigate fatigue properties of a low activation ferritic steel (9Cr-2W steel, JLF-1), low cycle fatigue tests were performed in air at room temperature under axial strain control for a complete push-pull condition. The strain rate was 0.4% s-1. Cyclic strain-hardening was observed within the initial 20 cycles, and then cyclic strain-softening occurred gradually until the final failure, though the plastic strain range did not change significantly. Tensile peak stresses in hysteresis curves measured at around half the number of cycles to failure depended on the total strain range. The drop in the peak stress by the cyclic strain-softening increased with decreasing total strain range. The regression curve of the total strain range against the fatigue life was formulated using the Manson-Coffin equation and the fatigue life of JLF-1 steel was compared with that of 8Cr-2W steel.

  14. Investigation of X-ray and optical solar flare activities during solar cycles 22 and 23

    NASA Astrophysics Data System (ADS)

    Akimov, L. A.; Belkina, I. L.; Bushueva, T. P.

    2003-02-01

    Daily X-ray flare indices (XFI) for the interval from January 1986 till June 2002 were calculated. The XFI behaviour during solar cycles 22 and 23 was studied. We compare the daily XFI with the daily optical flare indices (OFI) and with the International Relative Sunspot Numbers. The energy emitted by X-ray flares during 77 months of solar cycle 22 is shown to be about five times larger than the analogous value for the present solar cycle. We revealed statistically significant maxima in power spectra of the XFI and OFI. They correspond to periods of 25.5, 36.5, 73, 116, and 150d which presumably are appropriate to characteristic frequencies of the solar flare activity. A hypothesis on an possible effect of Mercury's variable electric charge on the origin of solar flares is proposed and corresponding estimates were made.

  15. The sleep-wake cycle and motor activity, but not temperature, are disrupted over the light-dark cycle in mice genetically depleted of serotonin.

    PubMed

    Solarewicz, Julia Z; Angoa-Perez, Mariana; Kuhn, Donald M; Mateika, Jason H

    2015-01-01

    We examined the role that serotonin has in the modulation of sleep and wakefulness across a 12-h:12-h light-dark cycle and determined whether temperature and motor activity are directly responsible for potential disruptions to arousal state. Telemetry transmitters were implanted in 24 wild-type mice (Tph2(+/+)) and 24 mice with a null mutation for tryptophan hydroxylase 2 (Tph2(-/-)). After surgery, electroencephalography, core body temperature, and motor activity were recorded for 24 h. Temperature for a given arousal state (quiet and active wake, non-rapid eye movement, and paradoxical sleep) was similar in the Tph2(+/+) and Tph2(-/-) mice across the light-dark cycle. The percentage of time spent in active wakefulness, along with motor activity, was decreased in the Tph2(+/+) compared with the Tph2(-/-) mice at the start and end of the dark cycle. This difference persisted into the light cycle. In contrast, the time spent in a given arousal state was similar at the remaining time points. Despite this similarity, periods of non-rapid-eye-movement sleep and wakefulness were less consolidated in the Tph2(+/+) compared with the Tph2(-/-) mice throughout the light-dark cycle. We conclude that the depletion of serotonin does not disrupt the diurnal variation in the sleep-wake cycle, motor activity, and temperature. However, serotonin may suppress photic and nonphotic inputs that manifest at light-dark transitions and serve to shorten the ultraradian duration of wakefulness and non-rapid-eye-movement sleep. Finally, alterations in the sleep-wake cycle following depletion of serotonin are unrelated to disruptions in the modulation of temperature.

  16. Frequencies of solar activity in laminated anhydrite of Upper Permian age (Zechstein-cycle 2)

    NASA Astrophysics Data System (ADS)

    Hiete, M.; Berner, U.

    2003-04-01

    Upper Permian Zechstein contains seven evaporitic cycles that were deposited in an epicontinental sea expanding from E-England to Poland. Zechstein-cycles 1 to 3 show a sequence of marine pelite, overlain by marine carbonate and evaporites (in the order sulfate, halite containing possibly anhydrite and potassium salts, and regressive sulphate at the top). Whereas the marginal facies of the lower sulphate horizon of Zechstein-cycle 2 (Stassfurt cycle) consists of massive anhydrite, its basin facies shows in the lower part a fine lamination of white anhydrite alternating with thin black organic carbon rich layers. These laminations are supposed to be annually deposited layers. The black laminae originate from the annual bloom of algae. Layer thickness is about 0.4 to 1.0 mm and increases from basin centre to more marginal positions. The individual layers can be traced over 300 km within the NW-German Basin. The previously described variability of layer thickness requires a forcing mechanism that is effective over long distances and must be also highly periodic. Also, varying layer thicknesses indicate varying anhydrite precipitation, i. e. probably changes in water temperatures which in turn point to climatic influences on the deposition of the layers. Here we re-examined records of cycle thickness (up to 700 laminae) determined by G. Richter-Bernburg in the 1950ties using modern techniques of time series analysis, e. g. wavelet analysis. We could detect cycles with periods of 10-14 years and 90 years which are close to known cycles of solar activity.

  17. Reverting p53 activation after recovery of cellular stress to resume with cell cycle progression.

    PubMed

    Lazo, Pedro A

    2017-05-01

    The activation of p53 in response to different types of cellular stress induces several protective reactions including cell cycle arrest, senescence or cell death. These protective effects are a consequence of the activation of p53 by specific phosphorylation performed by several kinases. The reversion of the cell cycle arrest, induced by p53, is a consequence of the phosphorylated and activated p53, which triggers its own downregulation and that of its positive regulators. The different down-regulatory processes have a sequential and temporal order of events. The mechanisms implicated in p53 down-regulation include phosphatases, deacetylases, and protein degradation by the proteasome or autophagy, which also affect different p53 protein targets and functions. The necessary first step is the dephosphorylation of p53 to make it available for interaction with mdm2 ubiquitin-ligase, which requires the activation of phosphatases targeting both p53 and p53-activating kinases. In addition, deacetylation of p53 is required to make lysine residues accessible to ubiquitin ligases. The combined action of these downregulatory mechanisms brings p53 protein back to its basal levels, and cell cycle progression can resume if cells have overcome the stress or damage situation. The specific targeting of these down-regulatory mechanisms can be exploited for therapeutic purposes in cancers harbouring wild-type p53.

  18. Daytime spikes in dopaminergic activity drive rapid mood-cycling in mice

    PubMed Central

    Sidor, Michelle M.; Spencer, Sade M.; Dzirasa, Kafui; Parekh, Puja K.; Tye, Kay M.; Warden, Melissa R.; Arey, Rachel N.; Enwright, John F; Jacobsen, Jacob PR; Kumar, Sunil; Remillard, Erin M; Caron, Marc G.; Deisseroth, Karl; McClung, Colleen A

    2014-01-01

    Disruptions in circadian rhythms and dopaminergic activity are involved in the pathophysiology of bipolar disorder, though their interaction remains unclear. Moreover, a lack of animal models that display spontaneous cycling between mood states has hindered our mechanistic understanding of mood switching. Here we find that mice with a mutation in the circadian Clock gene (ClockΔ19) exhibit rapid mood-cycling, with a profound manic-like phenotype emerging during the day following a period of euthymia at night. Mood cycling coincides with abnormal daytime spikes in ventral tegmental area (VTA) dopaminergic activity, tyrosine hydroxylase (TH) levels, and dopamine synthesis. To determine the significance of daytime increases in VTA dopamine activity to manic behaviors, we developed a novel optogenetic stimulation paradigm that produces a sustained increase in dopamine neuronal activity and find that this induces a manic-like behavioral state. Time-dependent dampening of TH activity during the day reverses manic-related behaviours in ClockΔ19 mice. Finally, we show that CLOCK acts as a negative regulator of TH transcription, revealing a novel molecular mechanism underlying cyclic changes in mood-related behaviour. Taken together, these studies have identified a mechanistic connection between circadian gene disruption and the precipitation of manic episodes in bipolar disorder. PMID:25560763

  19. K20E, an oxidative-coupling compound of methyl caffeate, exhibits anti-angiogenic activities through down-regulations of VEGF and VEGF receptor-2

    SciTech Connect

    Pan, Chun-Hsu; Lin, Wen-Hsin; Chien, Yi-Chung; Liu, Fon-Chang; Sheu, Ming-Jyh; Kuo, Yueh-Hsiung; Wu, Chieh-Hsi

    2015-01-15

    Anti-angiogenesis is one of the most popular clinical interventions for cancer chemotherapy. A series of synthesized derivative of methyl caffeate were used to evaluate the anti-angiogenic activity and to investigate possible pharmacological mechanisms in the present study. The most potent anti-angiogenic compound was evaluated in the experiments of murine allograft tumor model and Matrigel plug assay as well as cell models in the human umbilical vascular endothelial cells (HUVECs) and the LLC1 lung cancer cells. Our results suggested that K20E suppressed the tumor growth in the allograft tumor model and exhibited anti-angiogenic activity in Matrigel plug assay. Besides, HUVEC viability was found to be significantly reduced by arresting cell cycle at G{sub 2}/M phase and apoptosis. Cell migration, invasion, and tube formation of the HUVECs were also markedly suppressed by K20E treatment. K20E largely down-regulated the intracellular and secreted vascular endothelial growth factor (VEGF) in the LLC1 cancer cells. Besides, VEGF receptor-2 (VEGFR-2) and its downstream signaling cascades (AKT-mTOR and MEK1/2-ERK1/2) as well as gelatinases were all evidently reduced in the HUVECs treated with K20E. Inversely, K20E can up-regulate the expression levels of p53 and p21 proteins in the HUVECs. Based on these results, our study suggested that K20E possessed inhibiting angiogenesis through regulation of VEGF/VEGFR-2 and its downstream signaling cascades in the vascular endothelial cells (VECs). - Highlights: • K20E is an oxidative-coupling compound of methyl caffeate. • K20E exhibits anti-tumor and anti-angiogenesis effects. • K20E suppresses the expressions of VEGF and VEGF receptor-2 (VEGFR-2) proteins. • K20E deactivates VEGFR-2-mediated downstream signaling pathways to inhibit angiogenesis. • K20E up-regulates p53-p21 pathway to induce apoptosis and cell arrest at G2/M phase.

  20. Cell cycle dependent regulation of deoxycytidine kinase, deoxyguanosine kinase, and cytosolic 5'-nucleotidase I activity in MOLT-4 cells.

    PubMed

    Fyrberg, A; Mirzaee, S; Lotfi, K

    2006-01-01

    Activation of nucleoside analogues is dependent on kinases and 5'-nucleotidases and the balance between the activity of these enzymes. The purpose of this study was to analyze deoxycytidine kinase, deoxyguanosine kinase, and 4 different 5'-nucleotidases during cell cycle progression in MOLT-4 cells. The activity of both kinases was cell cycle dependent and increased during proliferation while the activity of cytosolic 5'-nucleotidase I decreased. We could show that the kinase activity was higher than the total nucleotidase activity, which was unchanged or decreased during cell cycle progression. These data may be important in designing modern combination therapy with nucleoside analogues.

  1. Postnatal telomere dysfunction induces cardiomyocyte cell-cycle arrest through p21 activation

    PubMed Central

    Aix, Esther; Gutiérrez-Gutiérrez, Óscar; Sánchez-Ferrer, Carlota; Aguado, Tania

    2016-01-01

    The molecular mechanisms that drive mammalian cardiomyocytes out of the cell cycle soon after birth remain largely unknown. Here, we identify telomere dysfunction as a critical physiological signal for cardiomyocyte cell-cycle arrest. We show that telomerase activity and cardiomyocyte telomere length decrease sharply in wild-type mouse hearts after birth, resulting in cardiomyocytes with dysfunctional telomeres and anaphase bridges and positive for the cell-cycle arrest protein p21. We further show that premature telomere dysfunction pushes cardiomyocytes out of the cell cycle. Cardiomyocytes from telomerase-deficient mice with dysfunctional telomeres (G3 Terc−/−) show precocious development of anaphase-bridge formation, p21 up-regulation, and binucleation. In line with these findings, the cardiomyocyte proliferative response after cardiac injury was lost in G3 Terc−/− newborns but rescued in G3 Terc−/−/p21−/− mice. These results reveal telomere dysfunction as a crucial signal for cardiomyocyte cell-cycle arrest after birth and suggest interventions to augment the regeneration capacity of mammalian hearts. PMID:27241915

  2. Development of engine activity cycles for the prime movers of unconventional natural gas well development.

    PubMed

    Johnson, Derek; Heltzel, Robert; Nix, Andrew; Barrow, Rebekah

    2017-03-01

    With the advent of unconventional natural gas resources, new research focuses on the efficiency and emissions of the prime movers powering these fleets. These prime movers also play important roles in emissions inventories for this sector. Industry seeks to reduce operating costs by decreasing the required fuel demands of these high horsepower engines but conducting in-field or full-scale research on new technologies is cost prohibitive. As such, this research completed extensive in-use data collection efforts for the engines powering over-the-road trucks, drilling engines, and hydraulic stimulation pump engines. These engine activity data were processed in order to make representative test cycles using a Markov Chain, Monte Carlo (MCMC) simulation method. Such cycles can be applied under controlled environments on scaled engines for future research. In addition to MCMC, genetic algorithms were used to improve the overall performance values for the test cycles and smoothing was applied to ensure regression criteria were met during implementation on a test engine and dynamometer. The variations in cycle and in-use statistics are presented along with comparisons to conventional test cycles used for emissions compliance.

  3. Dynamic DNA methylation patterns across the mouse and human IL10 genes during CD4+ T cell activation; influence of IL-27.

    PubMed

    Hedrich, Christian M; Ramakrishnan, Amritha; Dabitao, Djeneba; Wang, Fengying; Ranatunga, Dilini; Bream, Jay H

    2010-01-01

    IL-10 plays a critical role in controlling inflammation and the anti-inflammatory functions of IL-10 are regulated based on its coordinated expression from various cellular sources, most notably T cells. Although nearly all CD4+ subpopulations can express IL-10, surprisingly little is known about the molecular mechanisms which control IL-10 induction, particularly in humans. To examine the regulation of human IL-10 expression, we created the hIL10BAC transgenic mouse. As previously reported, we observed conservation of myeloid-derived IL-10 expression but found that human IL-10 was only weakly expressed in splenic CD4+ T cells from hIL10BAC mice. Since DNA methylation is an important determinant of gene expression profiles, we assessed the patterns of DNA methylation in the human and mouse IL10 genes in naïve and activated CD4+ T cells. Across mouse and human IL10 there were no obvious patterns of CpG methylation in naïve CD4+ T cells following polyclonal activation. Overall however, the human IL10 gene had significantly higher levels of DNA methylation. Interestingly, coculture with the IL-10-inducing cytokine IL-27 lead to a site-specific reduction in methylation of the mouse but not human IL10 gene. Demethylation was specifically localized to an intronic site adjacent to a known regulatory region. Our findings indicate that while the mouse and human IL10 genes undergo variable changes in DNA methylation during CD4+ T cell activation, IL-27 appears to influence DNA methylation in a particular intronic region thus associating with IL-10 expression.

  4. The 'golden age' of DNA methylation in neurodegenerative diseases.

    PubMed

    Fuso, Andrea

    2013-03-01

    DNA methylation reactions are regulated, in the first instance, by enzymes and the intermediates that constitute the 'so called' one-carbon metabolism. This is a complex biochemical pathway, also known as the homocysteine cycle, regulated by the presence of B vitamins (folate, B6, B12) and choline, among other metabolites. One of the intermediates of this metabolism is S-adenosylmethionine, which represent the methyl donor in all the DNA methyltransferase reactions in eukaryotes. The one-carbon metabolism therefore produces the substrate necessary for the transferring of a methyl group on the cytosine residues of DNA; S-adenosylmethionine also regulates the activity of the enzymes that catalyze this reaction, namely the DNA methyltransferases (DNMTs). Alterations of this metabolic cycle can therefore be responsible for aberrant DNA methylation processes possibly leading to several human diseases. As a matter of fact, increasing evidences indicate that a number of human diseases with multifactorial origin may have an epigenetic basis. This is also due to the great technical advances in the field of epigenetic research. Among the human diseases associated with epigenetic factors, aging-related and neurodegenerative diseases are probably the object of most intense research. This review will present the main evidences linking several human diseases to DNA methylation, with particular focus on neurodegenerative diseases, together with a short description of the state-of-the-art of methylation assays.

  5. Isolation of betulinic acid, its methyl ester and guaiane sesquiterpenoids with protein tyrosine phosphatase 1B inhibitory activity from the roots of Saussurea lappa C.B.Clarke.

    PubMed

    Choi, Ji Young; Na, Minkyun; Hyun Hwang, In; Ho Lee, Seung; Young Bae, Eun; Yeon Kim, Bo; Seog Ahn, Jong

    2009-01-08

    Activity-guided fractionation of a MeOH extract of the roots of Saussurea lappa C.B.Clarke (Compositae), using an in vitro protein tyrosine phosphatase 1B (PTP1B) inhibition assay, led to the isolation of four active constituents: betulinic acid (1), betulinic acid methyl ester (2), mokko lactone (3) and dehydrocostuslactone (4), along with nine inactive compounds. Our findings indicate that betulinic acid (1) and its methyl ester 2, as well as the two guaiane sesquiterpenoids 3 and 4 are potential lead moieties for the development of new PTP1B inhibitors.

  6. Measuring brain activity cycling (BAC) in long term EEG monitoring of preterm babies.

    PubMed

    Stevenson, Nathan J; Palmu, Kirsi; Wikström, Sverre; Hellström-Westas, Lena; Vanhatalo, Sampsa

    2014-07-01

    Measuring fluctuation of vigilance states in early preterm infants undergoing long term intensive care holds promise for monitoring their neurological well-being. There is currently, however, neither objective nor quantitative methods available for this purpose in a research or clinical environment. The aim of this proof-of-concept study was, therefore, to develop quantitative measures of the fluctuation in vigilance states or brain activity cycling (BAC) in early preterm infants. The proposed measures of BAC were summary statistics computed on a frequency domain representation of the proportional duration of spontaneous activity transients (SAT%) calculated from electroencephalograph (EEG) recordings. Eighteen combinations of three statistics and six frequency domain representations were compared to a visual interpretation of cycling in the SAT% signal. Three high performing measures (band energy/periodogram: R = 0.809, relative band energy/nonstationary frequency marginal: R = 0.711, g-statistic/nonstationary frequency marginal: R = 0.638) were then compared to a grading of sleep wake cycling based on the visual interpretation of the amplitude-integrated EEG trend. These measures of BAC are conceptually straightforward, correlate well with the visual scores of BAC and sleep wake cycling, are robust enough to cope with the technically compromised monitoring data available in intensive care units, and are recommended for further validation in prospective studies.

  7. Polarity Reversal of the Solar Photospheric Magnetic Field During Activity Cycle 24

    NASA Astrophysics Data System (ADS)

    Sun, Xudong; Hoeksema, Jon Todd; Liu, Yang; Zhao, Junwei

    2014-06-01

    The large-scale solar magnetic field reverses its polarity during the maximum phase of each activity cycle. As observed on the photosphere, active region (AR) magnetic flux migrates poleward in narrow, sheared streams resulted from large-scale flows and diffusion. A small net flux of the trailing sunspot polarity eventually aggregates at high latitudes, manifesting the poloidal field of the next cycle. We characterize this process for the ongoing cycle 24 based on four years' line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI). The axial dipole component reversed sign in early 2012, but the poleward flux migration was grossly out of phase in the two hemispheres. As a proxy, the northern polar field (taken as mean above 70 degrees latitude) switched from negative to positive in late 2012, whereas the southern remained positive as of March 2014. Three factors that are in line with the surface flux transport model may have contributed. First, AR emergence started and peaked earlier in the north. Second, several ARs with small or inverse tilt angles (w.r.t. the Joy's law) emerged in the south in late 2010. Third, meridional flow speed inferred from helioseismology varied greatly prior to 2013; slower streams (compared to a three-year mean at the same latitude) appeared earlier in the north. We correlate HMI with the long-running Wilcox Solar Observatory (WSO) dataset, and compare the current cycle with the previous three.

  8. c-Myc activates multiple metabolic networks to generate substrates for cell-cycle entry.

    PubMed

    Morrish, F; Isern, N; Sadilek, M; Jeffrey, M; Hockenbery, D M

    2009-07-09

    Cell proliferation requires the coordinated activity of cytosolic and mitochondrial metabolic pathways to provide ATP and building blocks for DNA, RNA and protein synthesis. Many metabolic pathway genes are targets of the c-myc oncogene and cell-cycle regulator. However, the contribution of c-Myc to the activation of cytosolic and mitochondrial metabolic networks during cell-cycle entry is unknown. Here, we report the metabolic fates of [U-(13)C] glucose in serum-stimulated myc(-/-) and myc(+/+) fibroblasts by (13)C isotopomer NMR analysis. We demonstrate that endogenous c-myc increased (13)C labeling of ribose sugars, purines and amino acids, indicating partitioning of glucose carbons into C1/folate and pentose phosphate pathways, and increased tricarboxylic acid cycle turnover at the expense of anaplerotic flux. Myc expression also increased global O-linked N-acetylglucosamine protein modification, and inhibition of hexosamine biosynthesis selectively reduced growth of Myc-expressing cells, suggesting its importance in Myc-induced proliferation. These data reveal a central organizing function for the Myc oncogene in the metabolism of cycling cells. The pervasive deregulation of this oncogene in human cancers may be explained by its function in directing metabolic networks required for cell proliferation.

  9. Ibuprofen and apigenin induce apoptosis and cell cycle arrest in activated microglia.

    PubMed

    Elsisi, Nahed S; Darling-Reed, Selina; Lee, Eunsook Y; Oriaku, Ebenezer T; Soliman, Karam F

    2005-02-28

    In case of injury or disease, microglia are recruited to the site of the pathology and become activated as evidenced by morphological changes and expression of pro-inflammatory cytokines. Evidence suggests that microglia proliferate by cell division to create gliosis at the site of pathological conditions such as the amyloid plaques in Alzheimer's disease and the substantia nigra of Parkinson's disease patients. The hyperactivation of microglia contributes to neurotoxicity. In the present study we tested the hypothesis that anti-inflammatory compounds modulate the progression of cell cycle and induce apoptosis of the activated cells. We investigated the effects of ibuprofen (non-steroidal anti-inflammatory drug) and apigenin (a flavonoid with anti-inflammatory and anti-proliferative properties) on the cell cycle of the murine microglial cell line BV-2. The findings indicate that apigenin-induced cell cycle arrest preferentially in the G2/M phase and ibuprofen caused S phase arrest. The binding of annexin V-FITC to the membranes of cells which indicates the apoptotic process were examined, whereas the DNA was stained with propidium iodide. Both apigenin and ibuprofen induced apoptosis significantly in early and late stages. The induction of apoptosis by ibuprofen and apigenin was confirmed using TUNEL assay, revealing that 25 microM apigenin and 250 microM ibuprofen significantly increased apoptosis in BV-2 cells. The results from the present study suggest that anti-inflammatory compounds might inhibit microglial proliferation by modulating the cell cycle progression and apoptosis.

  10. Inflows towards active regions and the modulation of the solar cycle: A parameter study

    NASA Astrophysics Data System (ADS)

    Martin-Belda, D.; Cameron, R. H.

    2017-01-01

    Aims: We aim to investigate how converging flows towards active regions affect the surface transport of magnetic flux, as well as their impact on the generation of the Sun's poloidal field. The inflows constitute a potential non-linear mechanism for the saturation of the global dynamo and may contribute to the modulation of the solar cycle in the Babcock-Leighton framework. Methods: We build a surface flux transport code incorporating a parametrized model of the inflows and run simulations spanning several cycles. We carry out a parameter study to assess how the strength and extension of the inflows affect the build-up of the global dipole field. We also perform simulations with different levels of activity to investigate the potential role of the inflows in the saturation of the global dynamo. Results: We find that the interaction of neighbouring active regions can lead to the occasional formation of single-polarity magnetic flux clumps that are inconsistent with observations. We propose the darkening caused by pores in areas of high magnetic field strength as a possible mechanism preventing this flux-clumping. We find that inflows decrease the amplitude of the axial dipole moment by 30%, relative to a no-inflows scenario. Stronger (weaker) inflows lead to larger (smaller) reductions of the axial dipole moment. The relative amplitude of the generated axial dipole is about 9% larger after very weak cycles than after very strong cycles. This supports the idea that the inflows are a non-linear mechanism that is capable of saturating the global dynamo and contributing to the modulation of the solar cycle within the Babcock-Leighton framework.

  11. Gene-Specific Promoter Methylation Status in Hormone-Receptor-Positive Breast Cancer Associates with Postmenopausal Body Size and Recreational Physical Activity

    PubMed Central

    McCullough, Lauren E.; Chen, Jia; White, Alexandra J.; Xu, Xinran; Cho, Yoon Hee; Bradshaw, Patrick T.; Eng, Sybil M.; Teitelbaum, Susan L.; Terry, Mary Beth; Garbowski, Gail; Neugut, Alfred I.; Hibshoosh, Hanina; Santella, Regina M.; Gammon, Marilie D.

    2015-01-01

    Introduction Breast cancer, the leading cancer diagnosis among American women, is positively associated with postmenopausal obesity and little or no recreational physical activity (RPA). However, the underlying mechanisms of these associations remain unresolved. Aberrant changes in DNA methylation may represent an early event in carcinogenesis, but few studies have investigated associations between obesity/RPA and gene methylation, particularly in postmenopausal breast tumors where these lifestyle factors are most relevant. Methods We used case-case unconditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CI) for the associations between body mass index (BMI=weight [kg]/height [m2]) in the year prior to diagnosis, or RPA (average hours/week), and methylation status (methylated vs. unmethylated) of 13 breast cancer-related genes in 532 postmenopausal breast tumor samples from the Long Island Breast Cancer Study Project. We also explored whether the association between BMI/RPA and estrogen/progesterone-receptor status (ER+PR+ vs. all others) was differential with respect to gene methylation status. Methylation-specific PCR and the MethyLight assay were used to assess gene methylation. Results BMI 25-29.9kg/m2, and perhaps BMI≥30kg/m2, was associated with methylated HIN1 in breast tumor tissue. Cases with BMI≥30kg/m2 were more likely to have ER+PR+ breast tumors in the presence of unmethylated ESR1 (OR=2.63, 95% CI 1.32-5.25) and women with high RPA were more likely to have ER+PR+ breast tumors with methylated GSTP1 (OR=2.33, 95% CI 0.79-6.84). Discussion While biologically plausible, our findings that BMI is associated with methylated HIN1 and BMI/RPA are associated with ER+PR+ breast tumors in the presence of unmethylated ESR1 and methylated GSTP1, respectively, warrant further investigation. Future studies would benefit from enrolling greater numbers of postmenopausal women and examining a larger panel of breast cancer

  12. Cell cycle arrest and activation of development in marine invertebrate deuterostomes.

    PubMed

    Costache, Vlad; McDougall, Alex; Dumollard, Rémi

    2014-08-01

    Like most metazoans, eggs of echinoderms and tunicates (marine deuterostomes, there is no data for the cephalochordates) arrest awaiting fertilization due to the activity of the Mos/MEK/MAPK cascade and are released from this cell cycle arrest by sperm-triggered Ca2+ signals. Invertebrate deuterostome eggs display mainly three distinct types of cell cycle arrest before fertilization mediated by potentially different cytostatic factors (CSF): one CSF causes arrest during meiotic metaphase I (MI-CSF in tunicates and some starfishes), another CSF likely causes arrest during meiotic metaphase II (amphioxus), and yet another form of CSF causes arrest to occur after meiotic exit during G1 of the first mitotic cycle (G1-CSF). In tunicates and echinoderms these different CSF activities have been shown to rely on the Mos//MAPK pathway for establishment and on Ca2+ signals for their inactivation. Despite these molecular similarities, release of MI-CSF arrest is caused by APC/C activation (to destroy cyclin B) whereas release from G1-CSF is caused by stimulating S phase and the synthesis of cyclins. Further research is needed to understand how both the Mos//MAPK cascade and Ca2+ achieve these tasks in different marine invertebrate deuterostomes. Another conserved feature of eggs is that protein synthesis of specific mRNAs is necessary to proceed through oocyte maturation and to maintain CSF-induced cell cycle arrest. Then activation of development at fertilization is accompanied by an increase in the rate of protein synthesis but the mechanisms involved are still largely unknown in most of the marine deuterostomes. How the sperm-triggered Ca2+ signals cause an increase in protein synthesis has been studied mainly in sea urchin eggs. Here we review these conserved features of eggs (arrest, activation and protein synthesis) focusing on the non-vertebrate deuterostomes.

  13. Role of calcium signaling in the activation of mitochondrial nitric oxide synthase and citric acid cycle.

    PubMed

    Traaseth, Nathaniel; Elfering, Sarah; Solien, Joseph; Haynes, Virginia; Giulivi, Cecilia

    2004-07-23

    An apparent discrepancy arises about the role of calcium on the rates of oxygen consumption by mitochondria: mitochondrial calcium increases the rate of oxygen consumption because of the activation of calcium-activated dehydrogenases, and by activating mitochondrial nitric oxide synthase (mtNOS), decreases the rates of oxygen consumption because nitric oxide is a competitive inhibitor of cytochrome oxidase. To this end, the rates of oxygen consumption and nitric oxide production were followed in isolated rat liver mitochondria in the presence of either L-Arg (to sustain a mtNOS activity) or N(G)-monomethyl-L-Arg (NMMA, a competitive inhibitor of mtNOS) under State 3 conditions. In the presence of NMMA, the rates of State 3 oxygen consumption exhibited a K(0.5) of 0.16 microM intramitochondrial free calcium, agreeing with those required for the activation of the Krebs cycle. By plotting the difference between the rates of oxygen consumption in State 3 with L-Arg and with NMMA at various calcium concentrations, a K(0.5) of 1.2 microM intramitochondrial free calcium was obtained, similar to the K(0.5) (0.9 microM) of the dependence of the rate of nitric oxide production on calcium concentrations. The activation of dehydrogenases, followed by the activation of mtNOS, would lead to the modulation of the Krebs cycle activity by the modulation of nitric oxide on the respiratory rates. This would ensue in changes in the NADH/NAD and ATP/ADP ratios, which would influence the rate of the cycle and the oxygen diffusion.

  14. Effectiveness and Student Perceptions of an Active Learning Activity Using a Headline News Story to Enhance In-Class Learning of Cell Cycle Regulation

    ERIC Educational Resources Information Center

    Dirks-Naylor, Amie J.

    2016-01-01

    An active learning activity was used to engage students and enhance in-class learning of cell cycle regulation in a PharmD level integrated biological sciences course. The aim of the present study was to determine the effectiveness and perception of the in-class activity. After completion of a lecture on the topic of cell cycle regulation,…

  15. The influence of sexual cycle on the MFO activity: A practical problem in biomonitoring

    SciTech Connect

    Fossi, C.; Leonzio, C.; Focardi, S. )

    1988-09-01

    During the last several years the induction of the mixed function oxidases system has been commonly used as a biochemical markers of xenobiotics contamination in aquatic, marine and terrestrial animals. The use of this index of stress in wild animals like birds has directly contributed to their ability to detect and understand the significance of the exposure to liphosoluble contaminants in the environment. Nevertheless, several intrinsic factors, such as for example the hormonal modulation during the sexual cycle, seems to significantly modify the activity of some monooxygenases. The aim of this paper is to underline, using three different examples of studies in wild birds exposed to PCBs, the role of the sexual cycles in the modification of MFO activity and consequently the importance of considering this aspect in planning biomonitoring.

  16. Activated carbon/Fe(3)O(4) nanoparticle composite: fabrication, methyl orange removal and regeneration by hydrogen peroxide.

    PubMed

    Do, Manh Huy; Phan, Ngoc Hoa; Nguyen, Thi Dung; Pham, Thi Thu Suong; Nguyen, Van Khoa; Vu, Thi Thuy Trang; Nguyen, Thi Kim Phuong

    2011-11-01

    In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe(3)O(4) nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe(3)O(4) nanoparticles, were fabricated by a modified impregnation method using HNO(3) as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO(3) (powdered activated carbon modified by HNO(3)) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe(3)O(4) nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide.

  17. Computation of Accurate Activation Barriers for Methyl-Transfer Reactions of Sulfonium and Ammonium Salts in Aqueous Solution.

    PubMed

    Gunaydin, Hakan; Acevedo, Orlando; Jorgensen, William L; Houk, K N

    2007-05-01

    The energetics of methyl-transfer reactions from dimethylammonium, tetramethylammonium, and trimethylsulfonium to dimethylamine were computed with density functional theory, MP2, CBS-QB3, and quantum mechanics/molecular mechanics (QM/MM) Monte Carlo methods. At the CBS-QB3 level, the gas-phase activation enthalpies are computed to be 9.9, 15.3, and 7.9 kcal/mol, respectively. MP2/6-31+G(d,p) activation enthalpies are in best agreement with the CBS-QB3 results. The effects of aqueous solvation on these reactions were studied with polarizable continuum model, generalized Born/surface area (GB/SA), and QM/MM Monte Carlo simulations utilizing free-energy perturbation theory in which the PDDG/PM3 semiempirical Hamiltonian for the QM and explicit TIP4P water molecules in the MM region were used. In the aqueous phase, all of these reactions proceed more slowly when compared to the gas phase, since the charged reactants are stabilized more than the transition structure geometries with delocalized positive charges. In order to obtain the aqueous-phase activation free energies, the gas-phase activation free energies were corrected with the solvation free energies obtained from single-point conductor-like polarizable continuum model and GB/SA calculations for the stationary points along the reaction coordinate.

  18. AMPK Causes Cell Cycle Arrest in LKB1-deficient Cells via Activation of CAMKK2

    PubMed Central

    Fogarty, Sarah; Ross, Fiona A.; Ciruelos, Diana Vara; Gray, Alexander; Gowans, Graeme J.; Hardie, D. Grahame

    2017-01-01

    The AMP-activated protein kinase (AMPK) is activated by phosphorylation at Thr172, either by the tumor suppressor kinase LKB1 or by an alternate pathway involving the Ca2+/calmodulin-dependent kinase, CAMKK2. Increases in AMP:ATP and ADP:ATP ratios, signifying energy deficit, promote allosteric activation and net Thr172 phosphorylation mediated by LKB1, so that the LKB1-AMPK pathway acts as an energy sensor. Many tumor cells carry loss-of-function mutations in the STK11 gene encoding LKB1, but LKB1 re-expression in these cells causes cell cycle arrest. Therefore, it was investigated as to whether arrest by LKB1 is caused by activation of AMPK or of one of the AMPK-related kinases, which are also dependent on LKB1 but are not activated by CAMKK2. In three LKB1-null tumor cell lines, treatment with the Ca2+ ionophore A23187 caused a G1-arrest that correlated with AMPK activation and Thr172 phosphorylation. In G361 cells, expression of a truncated, CAMKK2 mutant also caused G1-arrest similar to that caused by expression of LKB1, while expression of a dominant negative AMPK mutant, or a double knockout of both AMPK-α subunits, also prevented the cell cycle arrest caused by A23187. These mechanistic findings confirm that AMPK activation triggers cell cycle arrest, and also suggest that the rapid proliferation of LKB1-null tumor cells is due to lack of the restraining influence of AMPK. However, cell cycle arrest can be restored by re-expressing LKB1 or a constitutively active CAMKK2, or by pharmacological agents that increase intracellular Ca2+ and thus activate endogenous CAMKK2. Implications Evidence here reveals that the rapid growth and proliferation of cancer cells lacking the tumor suppressor LKB1 is due to reduced activity of AMPK, and suggests a therapeutic approach by which this block might be circumvented. PMID:27141100

  19. Arylesterase activity is associated with antioxidant intake and paraoxonase-1 (PON1) gene methylation in metabolic syndrome patients following an energy restricted diet.

    PubMed

    de la Iglesia, Rocio; Mansego, Maria L; Sánchez-Muniz, Francisco J; Zulet, M Angeles; Martinez, J Alfredo

    2014-01-01

    The arylesterase (ARE) activity linked to the paraoxonase-1 (PON1) gene is known to protect lipoproteins from oxidation and provide defense against metabolic syndrome (MetS) and cardiovascular diseases. The epigenetic regulation of enzymatic activities is gaining importance nowadays. This research aimed to assess the potential relationships between the ARE activity with the methylation levels of the PON1 gene transcriptional regulatory region, anthropometrics, biochemical markers and antioxidant dietary components. Forty-seven subjects (47 ± 10 y.o; BMI 36.2 ± 3.8 kg/m(2); 46.8 % female) with MetS features, who followed a six-month energy-restricted dietary weight-loss intervention, were included in this study (www.clinicaltrials.gov; NCT01087086). Anthropometric, biochemical, enzymatic and dietary data were assessed using validated procedures. PON1 transcriptional regulatory region methylation was analyzed by a microarray technical approach. Volunteers reduced ARE activity in parallel with body weight (p = 0.005), BMI (p = 0.006), total fat mass (p = 0.020), diastolic blood pressure (p = 0.018), mean blood pressure (p = 0.022) and triglycerides (p = 0.014). Methylation levels of some CpG sites of the PON1 gene correlated negatively with ARE activity (p < 0.05). Interestingly, dietary vitamin C (p = 0.001), tocopherols (p = 0.009) and lycopene (p = 0.038) were positively associated with ARE activity and showed an inverse correlation (p = 0.004, p = 0.029 and p = 0.021, respectively) with the methylation of some selected CpG sites of the PON1 gene. In conclusion, ARE activity decreased in parallel with MetS-related markers associated to the energy restriction, while dietary antioxidants might enhance the ARE activity by lowering the PON1 gene methylation in patients with MetS features.

  20. Arylesterase activity is associated with antioxidant intake and paraoxonase-1 (PON1) gene methylation in metabolic syndrome patients following an energy restricted diet

    PubMed Central

    de la Iglesia, Rocio; Mansego, Maria L.; Sánchez-Muniz, Francisco J.; Zulet, M. Angeles; Martinez, J. Alfredo

    2014-01-01

    The arylesterase (ARE) activity linked to the paraoxonase-1 (PON1) gene is known to protect lipoproteins from oxidation and provide defense against metabolic syndrome (MetS) and cardiovascular diseases. The epigenetic regulation of enzymatic activities is gaining importance nowadays. This research aimed to assess the potential relationships between the ARE activity with the methylation levels of the PON1 gene transcriptional regulatory region, anthropometrics, biochemical markers and antioxidant dietary components. Forty-seven subjects (47 ± 10 y.o; BMI 36.2 ± 3.8 kg/m2; 46.8 % female) with MetS features, who followed a six-month energy-restricted dietary weight-loss intervention, were included in this study (www.clinicaltrials.gov; NCT01087086). Anthropometric, biochemical, enzymatic and dietary data were assessed using validated procedures. PON1 transcriptional regulatory region methylation was analyzed by a microarray technical approach. Volunteers reduced ARE activity in parallel with body weight (p = 0.005), BMI (p = 0.006), total fat mass (p = 0.020), diastolic blood pressure (p = 0.018), mean blood pressure (p = 0.022) and triglycerides (p = 0.014). Methylation levels of some CpG sites of the PON1 gene correlated negatively with ARE activity (p < 0.05). Interestingly, dietary vitamin C (p = 0.001), tocopherols (p = 0.009) and lycopene (p = 0.038) were positively associated with ARE activity and showed an inverse correlation (p = 0.004, p = 0.029 and p = 0.021, respectively) with the methylation of some selected CpG sites of the PON1 gene. In conclusion, ARE activity decreased in parallel with MetS-related markers associated to the energy restriction, while dietary antioxidants might enhance the ARE activity by lowering the PON1 gene methylation in patients with MetS features. PMID:26417268

  1. Modifications in activation of lower limb muscles as a function of initial foot position in cycling.

    PubMed

    Padulo, Johnny; Powell, Douglas W; Ardigò, Luca P; Viggiano, Davide

    2015-08-01

    Cyclic movements, such as walking/cycling, require the activity of spinal-circuits, the central-pattern-generators (CPG). To our knowledge little work has been done to investigate the activation of these circuits, e.g., the muscular and kinematic activity during cycling initiation. This study aims to detail the muscle output properties as a function of the initial lower limb-position using a simple cycling paradigm. Therefore, subjects were required to pedal on a cycle-ergometer in seated position starting at different-crank-angles (0-150°). Surface-electromyography was recorded from the gluteus major (GL), vastus lateralis (VL), and gastrocnemius medialis (GM), while crank position was recorded using a linear-encoder. Gluteus major peak-activity (PA) occurred at 65.0±12.4° when starting with 0° initial crank position (ICP), while occurred maximally at 110.5±2.9 when starting with 70° ICP. Vastus lateralis PA occurred at 40.7±8.8° with 0° ICP, whereas with 70° ICP PA occurred at 103.4±4.0°. Similarly, GM PA occurred at 112.0±10.7° with 0° ICP, whereas with 70° ICP PA occurred at 142.5±4.2° PA. Gluteus major and gastrocnemius medialis showed similar PA phase shifts, which may suggest they are controlled by same local circuitry, in agreement with their common spinal origin, i.e., motoneurons pool in S1-S2.

  2. Multiplex Eukaryotic Transcription (In)activation: Timing, Bursting and Cycling of a Ratchet Clock Mechanism.

    PubMed

    Rybakova, Katja N; Bruggeman, Frank J; Tomaszewska, Aleksandra; Moné, Martijn J; Carlberg, Carsten; Westerhoff, Hans V

    2015-04-01

    Activation of eukaryotic transcription is an intricate process that relies on a multitude of regulatory proteins forming complexes on chromatin. Chromatin modifications appear to play a guiding role in protein-complex assembly on chromatin. Together, these processes give rise to stochastic, often bursting, transcriptional activity. Here we present a model of eukaryotic transcription that aims to integrate those mechanisms. We use stochastic and ordinary-differential-equation modeling frameworks to examine various possible mechanisms of gene regulation by multiple transcription factors. We find that the assembly of large transcription factor complexes on chromatin via equilibrium-binding mechanisms is highly inefficient and insensitive to concentration changes of single regulatory proteins. An alternative model that lacks these limitations is a cyclic ratchet mechanism. In this mechanism, small protein complexes assemble sequentially on the promoter. Chromatin modifications mark the completion of a protein complex assembly, and sensitize the local chromatin for the assembly of the next protein complex. In this manner, a strict order of protein complex assemblies is attained. Even though the individual assembly steps are highly stochastic in duration, a sequence of them gives rise to a remarkable precision of the transcription cycle duration. This mechanism explains how transcription activation cycles, lasting for tens of minutes, derive from regulatory proteins residing on chromatin for only tens of seconds. Transcriptional bursts are an inherent feature of such transcription activation cycles. Bursting transcription can cause individual cells to remain in synchrony transiently, offering an explanation of transcriptional cycling as observed in cell populations, both on promoter chromatin status and mRNA levels.

  3. S-Adenosylmethionine suppresses the expression of Smad3/4 in activated human hepatic stellate cells via Rac1 promoter methylation

    PubMed Central

    BIAN, KANGQI; ZHANG, FENG; WANG, TINGTING; ZOU, XIAOPING; DUAN, XUHONG; CHEN, GUANGXIA; ZHUGE, YUZHENG

    2016-01-01

    The aim of the present study was to investigate whether S-adenosylmethionine (SAM) was able to suppress activated human hepatic stellate cells (HSCs). Human LX-2 HSCs were cultured with SAM or NSC23766, and were transfected with plasmids encoding ras-related C3 botulinum toxin substrate 1 (Rac1) protein or an empty expression vector. Cell proliferation was detected by Cell Counting Kit-8. Cell migration and invasion were determined using the Transwell assay. The expression levels of Rac1 and Smad3/4 were detected by reverse transcription-quantitative polymerase chain reaction (PCR) or western blotting. The methylation status of Rac1 promoters was measured by methylation-specific PCR. The results demonstrated that SAM and NSC23766 suppressed the expression of Smad3/4 in LX-2 cells. The overexpression of Rac1 enhanced the proliferation, migration and invasion of LX-2 cells. In addition, compared with the control groups, a marked increase was observed in the protein expression levels of Smad3/4 in the LX-2 cells transfected with Rac1 plasmids. The methylation-specific PCR findings showed that SAM increased the methylation of Rac1 promoters. The results of the present study suggested that Rac1 enhanced the expression of Smad3/4 in activated HSCs; however, this increase may be suppressed by SAM-induced methylation of Rac1 promoters. PMID:26986629

  4. Can FES-Augmented Active Cycling Training Improve Locomotion in Post-Acute Elderly Stroke Patients?

    PubMed

    Peri, Elisabetta; Ambrosini, Emilia; Pedrocchi, Alessandra; Ferrigno, Giancarlo; Nava, Claudia; Longoni, Valentina; Monticone, Marco; Ferrante, Simona

    2016-06-13

    Recent studies advocated the use of active cycling coupled with functional electrical stimulation to induce neuroplasticity and enhance functional improvements in stroke adult patients. The aim of this work was to evaluate whether the benefits induced by such a treatment are superior to standard physiotherapy. A single-blinded randomized controlled trial has been performed on post-acute elderly stroke patients. Patients underwent FES-augmented cycling training combined with voluntary pedaling or standard physiotherapy. The intervention consisted of fifteen 30-minutes sessions carried out within 3 weeks. Patients were evaluated before and after training, through functional scales, gait analysis and a voluntary pedaling test. Results were compared with an age-matched healthy group. Sixteen patients completed the training. After treatment, a general improvement of all clinical scales was obtained for both groups. Only the mechanical efficiency highlighted a group effect in favor of the experimental group. Although a group effect was not found for any other cycling or gait parameters, the experimental group showed a higher percentage of change with respect to the control group (e.g. the gait velocity was improved of 35.4% and 25.4% respectively, and its variation over time was higher than minimal clinical difference for the experimental group only). This trend suggests that differences in terms of motor recovery between the two groups may be achieved increasing the training dose. In conclusion, this study, although preliminary, showed that FES-augmented active cycling training seems to be effective in improving cycling and walking ability in post-acute elderly stroke patients. A higher sample size is required to confirm results.

  5. Can FES-Augmented Active Cycling Training Improve Locomotion in Post-Acute Elderly Stroke Patients?

    PubMed Central

    Peri, Elisabetta; Ambrosini, Emilia; Pedrocchi, Alessandra; Ferrigno, Giancarlo; Nava, Claudia; Longoni, Valentina; Monticone, Marco; Ferrante, Simona

    2016-01-01

    Recent studies advocated the use of active cycling coupled with functional electrical stimulation to induce neuroplasticity and enhance functional improvements in stroke adult patients. The aim of this work was to evaluate whether the benefits induced by such a treatment are superior to standard physiotherapy. A single-blinded randomized controlled trial has been performed on post-acute elderly stroke patients. Patients underwent FES-augmented cycling training combined with voluntary pedaling or standard physiotherapy. The intervention consisted of fifteen 30-minutes sessions carried out within 3 weeks. Patients were evaluated before and after training, through functional scales, gait analysis and a voluntary pedaling test. Results were compared with an age-matched healthy group. Sixteen patients completed the training. After treatment, a general improvement of all clinical scales was obtained for both groups. Only the mechanical efficiency highlighted a group effect in favor of the experimental group. Although a group effect was not found for any other cycling or gait parameters, the experimental group showed a higher percentage of change with respect to the control group (e.g. the gait velocity was improved of 35.4% and 25.4% respectively, and its variation over time was higher than minimal clinical difference for the experimental group only). This trend suggests that differences in terms of motor recovery between the two groups may be achieved increasing the training dose. In conclusion, this study, although preliminary, showed that FES-augmented active cycling training seems to be effective in improving cycling and walking ability in post-acute elderly stroke patients. A higher sample size is required to confirm results. PMID:27990234

  6. Design, synthesis, and biological activity of 4-[(4-cyano-2-arylbenzyloxy)-(3-methyl-3H-imidazol-4-yl)methyl]benzonitriles as potent and selective farnesyltransferase inhibitors.

    PubMed

    Wang, Le; Wang, Gary T; Wang, Xilu; Tong, Yunsong; Sullivan, Gerry; Park, David; Leonard, Nicholas M; Li, Qun; Cohen, Jerry; Gu, Wen-Zhen; Zhang, Haiying; Bauch, Joy L; Jakob, Clarissa G; Hutchins, Charles W; Stoll, Vincent S; Marsh, Kennan; Rosenberg, Saul H; Sham, Hing L; Lin, Nan-Horng

    2004-01-29

    A novel series of 4-[(4-cyano-2-arylbenzyloxy)-(3-methyl-3H-imidazol-4-yl)methyl]benzonitriles have been synthesized as selective farnesyltransferase inhibitors using structure-based design. X-ray cocrystal structures of compound 20-FTase-HFP and A313326-FTase-HFP confirmed our initial design. The decreased interaction between the aryl groups and Ser 48 in GGTase-I binding site could be one possible reason to explain the improved selectivity for this new series of FTase inhibitors. Medicinal chemistry efforts led to the discovery of compound 64 with potent cellular activity (EC(50) = 3.5 nM) and outstanding pharmacokinetic profiles in dog (96% bioavailable, 18.4 h oral t(1/2), and 0.19 L/(h x kg) plasma clearance).

  7. An analysis of solar-cycle temporal relationships among activity indicators

    NASA Astrophysics Data System (ADS)

    Bachmann, K. T.; Maymani, H.; Nautiyal, K.; te Velde, V.

    2004-01-01

    Differences in the time development of solar activity indices are an important clue in the search for physical processes responsible for changing solar emission at various wavelengths. In this paper we describe our investigation of temporal relationships among two space-based indices, Lyman-α 121.6 nm emission (Lα) and the Mg II 280 nm core-to-wing ratio, and four ground-based indices - the 10.7 cm flux (F10), the He I 1083 nm equivalent width, the Ca II K 393.4 nm emission index, and the International Sunspot Number (ISN). We provide scatterplots of index pairs passed through a 2-year Gaussian filter during each available solar cycle, and we approximate the temporal relationships quantitatively as overall temporal offsets with uncertainties. We reconcile our findings with qualitative ideas concerning the variation of solar emissions with solar activity. Since the F10 and ISN time series are longer than four complete solar cycles, we are able to evaluate the reproducibility of temporal offsets over multiple solar cycles. The chief motivation for our work is to improve solar indicator analysis by providing a method of seeing and analyzing temporal relationships clearly and easily. We believe that future physical models of magnetic activity and spectral emissions in the solar chromosphere and transition region may make quantitative predictions of temporal relationships among full-disk solar indices for comparison with analyses such as ours.

  8. Cannabinoid receptor activation inhibits cell cycle progression by modulating 14-3-3β.

    PubMed

    Jung, Hye-Won; Park, Inae; Ghil, Sungho

    2014-09-01

    Cannabinoids display various pharmacological activities, including tumor regression, anti-inflammatory and neuroprotective effects. To investigate the molecular mechanisms underlying the pharmacological effects of cannabinoids, we used a yeast two-hybrid system to screen a mouse brain cDNA library for proteins interacting with type 1 cannabinoid receptor (CB1R). Using the intracellular loop 3 of CB1R as bait, we identified 14-3-3β as an interacting partner of CB1R and confirmed their interaction using affinity-binding assays. 14-3-3β has been reported to induce a cell cycle delay at the G2/M phase. We tested the effects of cannabinoids on cell cycle progression in HeLa cells synchronized using a double-thymidine block-and-release protocol and found an increase in the population of G2/M phase cells. We further found that CB1R activation augmented the interaction of 14-3-3β with Wee1 and Cdc25B, and promoted phosphorylation of Cdc2 at Tyr-15. These results suggest that cannabinoids induce cell cycle delay at the G2/M phase by activating 14-3-3β.

  9. Absence of substrate channeling between active sites in the Agrobacterium tumefaciens IspDF and IspE enzymes of the methyl erythritol phosphate pathway.

    PubMed

    Lherbet, Christian; Pojer, Florence; Richard, Stéphane B; Noel, Joseph P; Poulter, C D

    2006-03-21

    The conversion of 2-C-methyl-d-erythritol 4-phosphate (MEP) to 2-C-methyl-d-erythritol 2,4-cyclodiphosphate (cMEDP) in the MEP entry into the isoprenoid biosynthetic pathway occurs in three consecutive steps catalyzed by the IspD, IspE, and IspF enzymes, respectively. In Agrobacterium tumefaciens the ispD and ispF genes are fused to encode a bifunctional enzyme that catalyzes the first (synthesis of 4-diphosphocytidyl-2-C-methyl d-erythritol) and third (synthesis of 2-C-methyl-d-erythritol 2,4-cyclodiphosphate) steps. Sedimentation velocity experiments indicate that the bifunctional IspDF enzyme and the IspE protein associate in solution, raising the possibility of substrate channeling among the active sites in these two proteins. Kinetic evidence for substrate channeling was sought by measuring the time courses for product formation during incubations of MEP, CTP, and ATP with the IspDF and IspE proteins with and without an excess of the inactive IspE(D152A) mutant in the presence or absence of 30% (v/v) glycerol. The time dependencies indicate that the enzyme-generated intermediates are not transferred from the IspD active site in IspDF to the active site of IspE or from the active site in IspE to the active site of the IspF module of IspDF.

  10. Tidal, daily, and lunar-day activity cycles in the marine polychaete Nereis virens.

    PubMed

    Last, Kim S; Bailhache, Thierry; Kramer, Cas; Kyriacou, Charalambos P; Rosato, Ezio; Olive, Peter J W

    2009-02-01

    The burrow emergence activity of the wild caught ragworm Nereis virens Sars associated with food prospecting was investigated under various photoperiodic (LD) and simulated tidal cycles (STC) using a laboratory based actograph. Just over half (57%) of the animals under LD with STC displayed significant tidal (approximately 12.4 h) and/or lunar-day (approximately 24.8 h) activity patterns. Under constant light (LL) plus a STC, 25% of all animals were tidal, while one animal responded with a circadian (24.2 h) activity rhythm suggestive of cross-modal entrainment where the environmental stimulus of one period entrains rhythmic behavior of a different period. All peaks of activity under a STC, apart from that of the individual cross-modal entrainment case, coincided with the period of tank flooding. Under only LD without a STC, 49% of the animals showed nocturnal (approximately 24 h) activity. When animals were maintained under free-running LL conditions, 15% displayed significant rhythmicity with circatidal and circadian/circalunidian periodicities. Although activity cycles in N. virens at the population level are robust, at the individual level they are particularly labile, suggesting complex biological clock-control with multiple clock output pathways.

  11. Filterable redox cycling activity: a comparison between diesel exhaust particles and secondary organic aerosol constituents.

    PubMed

    McWhinney, Robert D; Badali, Kaitlin; Liggio, John; Li, Shao-Meng; Abbatt, Jonathan P D

    2013-04-02

    The redox activity of diesel exhaust particles (DEP) collected from a light-duty diesel passenger car engine was examined using the dithiothreitol (DTT) assay. DEP was highly redox-active, causing DTT to decay at a rate of 23-61 pmol min(-1) μg(-1) of particle used in the assay, which was an order of magnitude higher than ambient coarse and fine particulate matter (PM) collected from downtown Toronto. Only 2-11% of the redox activity was in the water-soluble portion, while the remainder occurred at the black carbon surface. This is in contrast to redox-active secondary organic aerosol constituents, in which upward of 90% of the activity occurs in the water-soluble fraction. The redox activity of DEP is not extractable by moderately polar (methanol) and nonpolar (dichloromethane) organic solvents, and is hypothesized to arise from redox-active moieties contiguous with the black carbon portion of the particles. These measurements illustrate that "Filterable Redox Cycling Activity" may therefore be useful to distinguish black carbon-based oxidative capacity from water-soluble organic-based activity. The difference in chemical environment leading to redox activity highlights the need to further examine the relationship between activity in the DTT assay and toxicology measurements across particles of different origins and composition.

  12. Lycopene enhances antioxidant enzyme activities and immunity function in N-methyl-N'-nitro-N-nitrosoguanidine-enduced gastric cancer rats.

    PubMed

    Luo, Cong; Wu, Xian-Guo

    2011-01-01

    To investigate anticancer effect of lycopene, we examined the effects of lycopene on the oxidative injury and immunity activities of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric cancer rats. The animals were divided into five groups. Group I served as the normal control and was given corn oil orally for 20 weeks. Group II were induced with MNNG 200 mg/kg body weight by oral gavage at days 0 and 14, and saturated NaCl (1 mL per rats) was given once every three days for four weeks until the end of the experimental period. Group III, IV and V were posttreated with lycopene (50, 100 and 150 mg/kg body weight, dissolved in corn oil) from the sixth week of MNNG (as in group II) induction up to the end of the experimental period. In the presence of MNNG, MDA and immunity levels were significantly increased, whereas enzymatic (SOD, CAT, and GPx) antioxidant activities were decreased in the treated rats compared with normal control rats. Administration of lycopene to gastric carcinoma-induced rats largely up-regulated the redox status and immunity activities to decrease the risk of cancer compared to group II. We conclude that up-regulation of antioxidants and immunity by lycopene treatment might be responsible for the anticancer effect in gastric carcinoma.

  13. A method for detecting the temporal sequence of muscle activation during cycling using MRI.

    PubMed

    Elder, Christopher P; Cook, Ryan N; Wilkens, Kenneth L; Chance, Marti A; Sanchez, Otto A; Damon, Bruce M

    2011-03-01

    Surface electromyography (EMG) can assess muscle recruitment patterns during cycling, but has limited applicability to studies of deep muscle recruitment and electrically stimulated contractions. We determined whether muscle recruitment timing could be inferred from MRI-measured transverse relaxation time constant (T(2)) changes and a cycle ergometer modified to vary power as a function of pedal angle. Six subjects performed 6 min of single-leg cycling under two conditions (E0°-230° and E90°-230°), which increased the power from 0°-230° and 90-230° of the pedal cycle, respectively. The difference condition produced a virtual power output from 0-180° (V0°-180°). Recruitment was assessed by integrating EMG over the pedal cycle (IEMG) and as the (post-pre) exercise T(2) change (ΔT(2)). For E0°-230°, the mean IEMG for vastus medialis and lateralis (VM/VL; 49.3 ± 3.9 mV·s; mean ± SE) was greater (P < 0.05) than that for E90°-230° (17.9 ± 1.9 mV·s); the corresponding ΔT(2) values were 8.7 ± 1.0 and 1.4 ± 0.5 ms (P < 0.05). For E0°-230° and E90°-230°, the IEMG values for biceps femoris/long head (BF(L)) were 37.7 ± 5.4 and 27.1 ± 5.6 mV·s (P > 0.05); the corresponding ΔT(2) values were 0.9 ± 0.9 and 1.5 ± 0.9 ms (P > 0.05). MRI data indicated activation of the semitendinosus and BF/short head for E0°-230° and E90°-230°. For V0°-180°, ΔT(2) was 7.2 ± 0.9 ms for VM/VL and -0.6 ± 0.6 ms for BF(L); IEMG was 31.5 ± 3.7 mV·s for VM/VL and 10.6 ± 7.0 mV·s for BF(L). MRI and EMG data indicate VM/VL activity from 0 to 180° and selected hamstring activity from 90 to 230°. Combining ΔT(2) measurements with variable loading allows the spatial and temporal patterns of recruitment during cycling to be inferred from MRI data.

  14. Cell cycle regulation and p53 activation by protein phosphatase 2C alpha.

    PubMed

    Ofek, Paula; Ben-Meir, Daniella; Kariv-Inbal, Zehavit; Oren, Moshe; Lavi, Sara

    2003-04-18

    Protein phosphatase 2C (PP2C) dephosphorylates a broad range of substrates, regulating stress response and growth-related pathways in both prokaryotes and eukaryotes. We now demonstrate that PP2C alpha, a major mammalian isoform, inhibits cell growth and activates the p53 pathway. In 293 cell clones, in which PP2C alpha expression is regulated by a tetracycline-inducible promoter, PP2C alpha overexpression led to G(2)/M cell cycle arrest and apoptosis. Furthermore, PP2C alpha induced the expression of endogenous p53 and the p53-responsive gene p21. Activation of the p53 pathway by PP2C alpha took place both in cells harboring endogenous p53, as well as in p53-null cells transfected with exogenous p53. Induction of PP2C alpha resulted in an increase in the overall levels of p53 protein as well as an augmentation of p53 transcription activity. The dephosphorylation activity of PP2C alpha is essential to the described phenomena, as none of these effects was detected when an enzymatically inactive PP2C alpha mutant was overexpressed. p53 plays an important role in PP2C alpha-directed cell cycle arrest and apoptosis because perturbation of p53 expression in human 293 cells by human papillomavirus E6 led to a significant increase in cell survival. The role of PP2C alpha in p53 activation is discussed.

  15. Activated carbons from end-products of tree nut and tree fruit production as sorbents for removing methyl bromide in ventilation effluent from postharvest chamber fumigation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    End-products of tree nuts and tree fruits grown in California, USA were evaluated for the ability to remove methyl bromide from the ventilation effluent of postharvest chamber fumigations. Activated carbon sorbents from walnut and almond shells as well as peach and prune pits were prepared using dif...

  16. Design synthesis and structure–activity relationship of 5-substituted (tetrahydronaphthalen-2yl)methyl with N-phenyl-N-(piperidin-2-yl) propionamide derivatives as opioid ligands

    PubMed Central

    Deekonda, Srinivas; Rankin, David; Davis, Peg; Lai, Josephine; Vanderah, Todd. W.; Porecca, Frank; Hruby, Victor J.

    2016-01-01

    Here, we report the design, synthesis and structure activity relationship of novel small molecule opioid ligands based on 5-amino substituted (tetrahydronaphthalen-2-yl)methyl moiety with N-phenyl-N-(piperidin-2-yl)propionamide derivatives. We synthesized various molecules including amino, amide and hydroxy substitution on the 5th position of the (tetrahydronaphthalen-2-yl)methyl moiety. In our further designs we replaced the (tetrahydronaphthalen-2-yl)methyl moiety with benzyl and phenethyl moiety. These N-phenyl-N-(piperidin-2-yl)propionamide analogues showed moderate to good binding affinities (850–4 nM) and were selective towards the μ opioid receptor over the δ opioid receptors. From the structure activity relationship studies, we found that a hydroxyl substitution at the 5th position of (tetrahydronapthalen-2yl)methyl group, ligands 19 and 20, showed excellent binding affinities 4 and 5 nM, respectively, and 1000 fold selectivity towards the μ opioid relative to the delta opioid receptor. The ligand 19 showed potent agonist activities 75 ± 21 nM, and 190 ± 42 nM in the GPI and MVD assays. Surprisingly the fluoro analogue 20 showed good agonist activities in MVD assays 170 ± 42 nM, in contrast to its binding affinity results. PMID:26712115

  17. Promoter analysis of mouse Scn3a gene and regulation of the promoter activity by GC box and CpG methylation.

    PubMed

    Deng, Guang-Fei; Qin, Jia-Ming; Sun, Xun-Sha; Kuang, Zu-Ying; Su, Tao; Zhao, Qi-Hua; Shi, Yi-Wu; Liu, Xiao-Rong; Yu, Mei-Juan; Yi, Yong-Hong; Liao, Wei-Ping; Long, Yue-Sheng

    2011-06-01

    Voltage-gated sodium channel α-subunit type III (Na(v)1.3) is mainly expressed in the central nervous system and is associated with neurological disorders. The expression of mouse Scn3a product (Na(v)1.3) mainly occurs in embryonic and early postnatal brain but not in adult brain. Here, we report for the first time the identification and characterization of the mouse Scn3a gene promoter region and regulation of the promoter activity by GC box and CpG methylation. Luciferase assay showed that the promoter region F1.2 (nt -1,049 to +157) had significantly higher activity in PC12 cells, comparing with that in SH-SY5Y cells and HEK293 cells. A stepwise 5' truncation of the promoter region found that the minimal functional promoter located within the region nt -168 to +157. Deletion of a GC box (nt -254 to -258) in the mouse Scn3a promoter decreased the promoter activity. CpG methylation of the F1.2 without the GC box completely repressed the promoter activity, suggesting that the GC box is a critical element in the CpG-methylated Scn3a promoter. These results suggest that the GC box and CpG methylation might play important roles in regulating mouse Scn3a gene expression.

  18. A TGFβ-PRMT5-MEP50 Axis Regulates Cancer Cell Invasion through Histone H3 and H4 Arginine Methylation Coupled Transcriptional Activation and Repression

    PubMed Central

    Chen, Hongshan; Lorton, Benjamin; Gupta, Varun; Shechter, David

    2016-01-01

    Protein arginine methyltransferase 5 (PRMT5) complexed with MEP50/WDR77 catalyzes arginine methylation on histones and other proteins. PRMT5-MEP50 activity is elevated in cancer cells and its expression is highly correlated with poor prognosis in many human tumors. We demonstrate that PRMT5-MEP50 is essential for transcriptional regulation promoting cancer cell invasive phenotypes in lung adenocarcinoma, lung squamous cell carcinoma and breast carcinoma cancer cells. RNA-Seq transcriptome analysis demonstrated that PRMT5 and MEP50 are required to maintain expression of metastasis and Epithelial-to-mesenchymal transition (EMT) markers and to potentiate an epigenetic mechanism of the TGFβ response. We show that PRMT5-MEP50 activity both positively and negatively regulates expression of a wide range of genes. Exogenous TGFβ promotes EMT in a unique pathway of PRMT5-MEP50 catalyzed histone mono- and dimethylation of chromatin at key metastasis suppressor and EMT genes, defining a new mechanism regulating cancer invasivity. PRMT5 methylation of histone H3R2me1 induced transcriptional activation by recruitment of WDR5 and concomitant H3K4 methylation at targeted genes. In parallel, PRMT5 methylation of histone H4R3me2s suppressed transcription at distinct genomic loci. Our decoding of histone methylarginine at key genes supports a critical role for complementary PRMT5-MEP50 transcriptional activation and repression in cancer invasion pathways and in response to TGFβ stimulation and therefore and orients future chemotherapeutic opportunities. PMID:27270440

  19. DNA methylation and differentiation.

    PubMed Central

    Michalowsky, L A; Jones, P A

    1989-01-01

    The methylation of specific cytosine residues in DNA has been implicated in regulating gene expression and facilitating functional specialization of cellular phenotypes. Generally, the demethylation of certain CpG sites correlates with transcriptional activation of genes. 5-Azacytidine is an inhibitor of DNA methylation and has been widely used as a potent activator of suppressed genetic information. Treatment of cells with 5-azacytidine results in profound phenotypic alterations. The drug-induced hypomethylation of DNA apparently perturbs DNA-protein interactions that may consequently alter transcriptional activity and cell determination. The inhibitory effect of cytosine methylation may be exerted via altered DNA-protein interactions specifically or may be transduced by a change in the conformation of chromatin. Recent studies have demonstrated that cytosine methylation also plays a central role in parental imprinting, which in turn determines the differential expression of maternal and paternal genomes during embryogenesis. In other words, methylation is the mechanism whereby the embryo retains memory of the gametic origin of each component of genetic information. A memory of this type would probably persist during DNA replication and cell division as methylation patterns are stable and heritable. PMID:2466640

  20. Sub- and Quasi-Centurial Cycles in Solar and Geomagnetic Activity Data Series

    NASA Astrophysics Data System (ADS)

    Komitov, B.; Sello, S.; Duchlev, P.; Dechev, M.; Penev, K.; Koleva, K.

    2016-07-01

    The subject of this paper is the existence and stability of solar cycles with durations in the range of 20-250 years. Five types of data series are used: 1) the Zurich series (1749-2009 AD), the mean annual International sunspot number Ri, 2) the Group sunspot number series Rh (1610-1995 AD), 3) the simulated extended sunspot number from Extended time series of Solar Activity Indices (ESAI) (1090-2002 AD), 4) the simulated extended geomagnetic aa-index from ESAI (1099-2002 AD), 5) the Meudon filament series (1919-1991 AD). Two principally independent methods of time series analysis are used: the T-R periodogram analysis (both in standard and ``scanning window'' regimes) and the wavelet-analysis. The obtained results are very similar. A strong cycle with a mean duration of 55-60 years is found to exist in all series. On the other hand, a strong and stable quasi 110-120 years and ˜200-year cycles are obtained in all of these series except in the Ri one. The high importance of the long term solar activity dynamics for the aims of solar dynamo modeling and predictions is especially noted.

  1. Development of 23 Cycles Activity in Northern and Southern Hemispheres of the Sun

    NASA Astrophysics Data System (ADS)

    Ryabov, M. I.; Sukharev, A. L.; Lukashuk, S. A.

    On an example of the 23rd cycle of solar activity the basic properties of its development in northern and southern hemispheres were researched (daily values of Wolf Sunspot Number - W, the daily values of Sun spots areas - Sp and daily values of flare index - FI.) Effects of application of full-scale Wavelet analysis for studying the temporary structure of formation of a solar cycle show the difference in northern and southern hemispheres. The "leading" periods (in northern hemisphere - 340 days, and in southern hemisphere - 709 days) differ. Thus, the activity period in two years is predominate in southern hemisphere. The "leading" period for the flare index for northern hemisphere is 555 days, and for southern hemisphere is 709 days. In general the basic periods W in northern hemisphere are in the range of 37-555 days, and in southern - 78-906 days, SpN (61-906 days), SpS (61-1477 days), FIN (37-555 days), FIS (23-709 days), FIS - (14709 days) depending on the phase of solar cycle.

  2. Self-oocyte activation and parthenogenesis: an unusual outcome of a misconducted IVF cycle.

    PubMed

    Socolov, Razvan; Ebner, Thomas; Gorduza, Vlad; Martiniuc, Violeta; Angioni, Stefano; Socolov, Demetra

    2015-07-01

    A rare cause of infertility is the lack of fertilisation with the spontaneous activation of oocytes, leading to parthenogenesis. We present such a case. The patient was a G1P0 38-year-old woman of African ethnicity, who requested an in vitro fertilisation (IVF) with donor sperm. She received a stimulation protocol of 75 IU of FSH/LH from day 3 of the cycle, which she interrupted after 2 d, and restarted with the same dosage for another 3 d from day 7, plus one administration of GnRH antagonist in day 10 of the cycle. With a follicle reaching 19 mm on day 11, estradiol of 325 ng/ml, ovulation was induced with hMG 5000 UI, and oocyte pick-up performed at 30 h. One oocyte was retrieved, and good-quality sperms were added to the insemination procedure. No fecundation occurred at 20 h, with the extruded oocyte separated from the granulosa wall. At 40 h and 64 h the aspect was of three cells, one cell with one nucleus, the others with high granulation and no visible nuclei. This case shows an unusual self-activation oocyte in a poorly managed IVF cycle. The patient will be further evaluated, to decide if a better managed stimulation protocol would prevent recurrence.

  3. Developmentally programmed 3' CpG island methylation confers tissue- and cell-type-specific transcriptional activation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During development, a small but significant number of CpG islands (CGIs) becomes methylated. The timing of developmentally programmed CGI methylation and associated mechanisms of transcriptional regulation during cellular differentiation, however, remain poorly characterized. Here we used genome-wid...

  4. Cell cycle effect on the activity of deoxynucleoside analogue metabolising enzymes

    SciTech Connect

    Fyrberg, Anna; Albertioni, Freidoun; Lotfi, Kourosh . E-mail: koulo@imv.liu.se

    2007-06-15

    Deoxynucleoside analogues (dNAs) are cytotoxic towards both replicating and indolent malignancies. The impact of fluctuations in the metabolism of dNAs in relation to cell cycle could have strong implications regarding the activity of dNAs. Deoxycytidine kinase (dCK) and deoxyguanosine kinase (dGK) are important enzymes for phosphorylation/activation of dNAs. These drugs can be dephosphorylated/deactivated by 5'-nucleotidases (5'-NTs) and elevated activities of 5'-NTs and decreased dCK and/or dGK activities represent resistance mechanisms towards dNAs. The activities of dCK, dGK, and three 5'-NTs were investigated in four human leukemic cell lines in relationship to cell cycle progression and cytotoxicity of dNAs. Synchronization of cell cultures to arrest in G0/G1 by serum-deprivation was performed followed by serum-supplementation for cell cycle progression. The activities of dCK and dGK increased up to 3-fold in CEM, HL60, and MOLT-4 cells as they started to proliferate, while the activity of cytosolic nucleotidase I was reduced in proliferating cells. CEM, HL60, and MOLT-4 cells were also more sensitive to cladribine, cytarabine, 9-{beta}-D-arabinofuranosylguanine and clofarabine than K562 cells which demonstrated lower levels and less alteration of these enzymes and were least susceptible to the cytotoxic effects of most dNAs. The results suggest that, in the cell lines studied, the proliferation process is associated with a general shift in the direction of activation of dNAs by inducing activities of dCK/dGK and reducing the activity of cN-I which is favourable for the cytotoxic effects of cladribine, cytarabine and, 9-{beta}-D-arabinofuranosylguanine. These results emphasize the importance of cellular proliferation and dNA metabolism by both phosphorylation and dephosphorylation for susceptibility to dNAs. It underscores the need to understand the mechanisms of action and resistance to dNAs in order to increase efficacy of dNAs treatment by new rational.

  5. Use of benzo analogs to enhance antimycotic activity of kresoxim methyl for control of aflatoxigenic fungal pathogens

    PubMed Central

    Kim, Jong H.; Mahoney, Noreen; Chan, Kathleen L.; Campbell, Bruce C.; Haff, Ronald P.; Stanker, Larry H.

    2014-01-01

    The aim of this study was to examine two benzo analogs, octylgallate (OG) and veratraldehyde (VT), as antifungal agents against strains of Aspergillus parasiticus and A.flavus (toxigenic or atoxigenic). Both toxigenic and atoxigenic strains used were capable of producing kojic acid, another cellular secondary product. A. fumigatus was used as a genetic model for this study. When applied independently, OG exhibits considerably higher antifungal activity compared to VT. The minimum inhibitory concentrations (MICs) of OG were 0.3–0.5 mM, while that of VT were 3.0–5.0 mM in agar plate-bioassays. OG or VT in concert with the fungicide kresoxim methyl (Kre-Me; strobilurin) greatly enhanced sensitivity of Aspergillus strains to Kre-Me. The combination with OG also overcame the tolerance of A. fumigatus mitogen-activated protein kinase (MAPK) mutants to Kre-Me. The degree of compound interaction resulting from chemosensitization of the fungi by OG was determined using checkerboard bioassays, where synergistic activity greatly lowered MICs or minimum fungicidal concentrations. However, the control chemosensitizer benzohydroxamic acid, an alternative oxidase inhibitor conventionally applied in concert with strobilurin, did not achieve synergism. The level of antifungal or chemosensitizing activity was also “compound—strain” specific, indicating differential susceptibility of tested strains to OG or VT, and/or heat stress. Besides targeting the antioxidant system, OG also negatively affected the cell wall-integrity pathway, as determined by the inhibition of Saccharomyces cerevisiae cell wall-integrity MAPK pathway mutants. We concluded that certain benzo analogs effectively inhibit fungal growth. They possess chemosensitizing capability to increase efficacy of Kre-Me and thus, could reduce effective dosages of strobilurins and alleviate negative side effects associated with current antifungal practices. OG also exhibits moderate antiaflatoxigenic activity. PMID

  6. Intracellular and membrane-damaging activities of methyl gallate isolated from Terminalia chebula against multidrug-resistant Shigella spp.

    PubMed

    Acharyya, Saurabh; Sarkar, Prodipta; Saha, Dhira R; Patra, Amarendra; Ramamurthy, T; Bag, Prasanta K

    2015-08-01

    Shigella spp. (Shigella dysenteriae, Shigella flexneri, Shigella boydii and Shigella sonnei) cause bacillary dysentery (shigellosis), which is characterized by bloody mucous diarrhoea. Although a variety of antibiotics have been effective for treatment of shigellosis, options are becoming limited due to globally emerging drug resistance. In the present study, in vitro antibacterial activity of methyl gallate (MG) isolated from Terminalia chebula was determined by performing MIC, minimal bactericidal concentration (MBC) and time-kill kinetic studies. Bacterial membrane-damaging activity of MG was determined by membrane perturbation and transmission electron microscopy (TEM). Cellular drug accumulation, cell infection and assessment of intracellular activities of MG and reference antibiotics were performed using HeLa cell cultures. The bactericidal activity of MG against multidrug-resistant (MDR) Shigella spp. in comparison with other commonly used drugs including fluoroquinolone was demonstrated here. TEM findings in the present study revealed that MG caused the total disintegration of inner and outer membranes, and leakage of the cytoplasmic contents of S. dysenteriae. The level of accumulation of MG and tetracycline in HeLa cells incubated for 24  h was relatively higher than that of ciprofloxacin and nalidixic acid (ratio of intracellular concentration/extracellular concentration of antibiotic for MG and tetracycline>ciprofloxacin and nalidixic acid). The viable number of intracellular S. dysenteriae was decreased in a time-dependent manner in the presence of MG (4 × MBC) and reduced to zero within 20  h. The significant intracellular activities of MG suggested that it could potentially be used as an effective antibacterial agent for the treatment of severe infections caused by MDR Shigella spp.

  7. Impact of activation methods on persulfate oxidation of methyl tert-butyl ether.

    PubMed

    Deng, Dayi; Peng, Libin; Guan, Mengyun; Kang, Yuan

    2014-01-15

    To provide guidance on the selection of proper persulfate processes for the remediation of MTBE contaminated groundwater, MTBE aqueous solutions were treated with three common field persulfate processes including heat activated persulfate, Fe(III)-EDTA activated persulfate and alkaline persulfate, respectively. The results were compared with MTBE oxidation by Fenton's reagent and persulfate alone at 25°C. The impact of the activating conditions on the fate of MTBE and its daughter products was investigated. Heat activation at 40°C offered the most rapid removal of MTBE and its daughter products, while Fe(III)-EDTA activation showed higher efficiency of MTBE removal but low removal efficiency of its daughter products. On the other hand, alkaline persulfate showed slower kinetics for the removal of MTBE and less accumulation of the daughter products. Furthermore, tert-butyl alcohol and acetone were observed as the main purgeable daughter products along with a small amount of tert-butyl formate in persulfate oxidation of MTBE, while tert-butyl formate, tert-butyl alcohol and acetone were the main products in Fenton oxidation. Mechanistic analysis suggests that degradation of MTBE by persulfate most likely happens via non-oxygen demand pathways, different from the dominant oxygen demand degradation pathways observed in Fenton oxidation.

  8. Recent Activities in Research of the Combined Cycle Engine at JAXA

    NASA Astrophysics Data System (ADS)

    Tani, Kouichiro; Tomioka, Sadatake; Kato, Kanenori; Ueda, Syuichi; Takegoshi, Masao

    Recent activities of the researches on the rocket based combined cycle engine in Japan Aerospace Exploration Agency are summarized. Aiming to realize the flight test in 10 years, JAXA has been making sub-scale model experiments as well as a series of component tests. In 08 fiscal year, sub-scale tests were carried out in Mach 6 flight condition and the stable ramjet combustion was confirmed following the successful ramjet mode establishment in Mach 4 condition in previous year. Some improvements of flow modeling inside the combustor and the ejector analysis were also achieved. With the scramjet mode analysis due in ’09 fiscal year, the designing method of the combined cycle engine will be improved and the next test engine will be launched.

  9. Activation of MAPK/ERK signaling by Burkholderia pseudomallei cycle inhibiting factor (Cif)

    PubMed Central

    Ng, Mei Ying; Wang, Mei; Casey, Patrick J.; Gan, Yunn-Hwen; Hagen, Thilo

    2017-01-01

    Cycle inhibiting factors (Cifs) are virulence proteins secreted by the type III secretion system of some Gram-negative pathogenic bacteria including Burkholderia pseudomallei. Cif is known to function to deamidate Nedd8, leading to inhibition of Cullin E3 ubiquitin ligases (CRL) and consequently induction of cell cycle arrest. Here we show that Cif can function as a potent activator of MAPK/ERK signaling without significant activation of other signaling pathways downstream of receptor tyrosine kinases. Importantly, we found that the ability of Cif to activate ERK is dependent on its deamidase activity, but independent of Cullin E3 ligase inhibition. This suggests that apart from Nedd8, other cellular targets of Cif-dependent deamidation exist. We provide evidence that the mechanism involved in Cif-mediated ERK activation is dependent on recruitment of the Grb2-SOS1 complex to the plasma membrane. Further investigation revealed that Cif appears to modify the phosphorylation status of SOS1 in a region containing the CDC25-H and proline-rich domains. It is known that prolonged Cullin E3 ligase inhibition leads to cellular apoptosis. Therefore, we hypothesize that ERK activation is an important mechanism to counter the pro-apoptotic effects of Cif. Indeed, we show that Cif dependent ERK activation promotes phosphorylation of the proapoptotic protein Bim, thereby potentially conferring a pro-survival signal. In summary, we identified a novel deamidation-dependent mechanism of action of the B. pseudomallei virulence factor Cif/CHBP to activate MAPK/ERK signaling. Our study demonstrates that bacterial proteins such as Cif can serve as useful molecular tools to uncover novel aspects of mammalian signaling pathways. PMID:28166272

  10. Proteomic and activity profiles of ascorbate-glutathione cycle enzymes in germinating barley embryo.

    PubMed

    Bønsager, Birgit C; Shahpiri, Azar; Finnie, Christine; Svensson, Birte

    2010-10-01

    Enzymes involved in redox control are important during seed germination and seedling growth. Ascorbate-glutathione cycle enzymes in barley embryo extracts were monitored both by 2D-gel electrophoresis and activity measurements from 4 to 144 h post imbibition (PI). Strikingly different activity profiles were observed. No ascorbate peroxidase (APX) activity was present in mature seeds but activity was detected after 24 h PI and increased 14-fold up to 144 h PI. In contrast, dehydroascorbate reductase (DHAR) activity was present at 4h PI and first decreased by 9-fold until 72 h PI followed by a 5-fold increase at 144 h PI. Glutathione reductase and monodehydroascorbate reductase activities were also detected at 4 h PI, and showed modest increases of 1.8- and 2.7-fold, respectively, by 144 h PI. The combination of functional analysis with the proteomics approach enabled correlation of the activity profiles and protein abundance. While gel spots containing APX showed intensity changes consistent with the activity profile from 0 to 72 h PI, DHAR spot intensities indicated that post-translational regulation may be responsible for the observed changes in activity. Transcript profiling, 2D-western blotting and mass spectrometric characterization of multiple APX spots demonstrated the presence of APX1 and minor amounts of APX2.

  11. Agonist-mediated assembly of the crustacean methyl farnesoate receptor

    PubMed Central

    Kakaley, Elizabeth K. Medlock; Wang, Helen Y.; LeBlanc, Gerald A.

    2017-01-01

    The methyl farnesoate receptor (MfR) orchestrates aspects of reproduction and development such as male sex determination in branchiopod crustaceans. Phenotypic endpoints regulated by the receptor have been well-documented, but molecular interactions involved in receptor activation remain elusive. We hypothesized that the MfR subunits, methoprene-tolerant transcription factor (Met) and steroid receptor coactivator (SRC), would be expressed coincident with the timing of sex programming of developing oocytes by methyl farnesoate in daphnids. We also hypothesized that methyl farnesoate activates MfR assembly. Met mRNA was expressed rhythmically during the reproductive cycle, with peak mRNA accumulation just prior period of oocytes programming of sex. Further, we revealed evidence that Met proteins self-associate in the absence of methyl farnesoate, and that the presence of methyl farnesoate stimulates dissociation of Met multimers with subsequent association with SRC. Results demonstrated that the Met subunit is highly dynamic in controlling the action of methyl farnesoate through temporal variation in its expression and availability for receptor assembly. PMID:28322350

  12. Structure-activity relationship for quaternary ammonium compounds hybridized with poly(methyl methacrylate).

    PubMed

    Melo, Leticia D; Palombo, Renata R; Petri, Denise F S; Bruns, Michael; Pereira, Edla M A; Carmona-Ribeiro, Ana M

    2011-06-01

    Hybrid films from poly (methylmethacrylate) (PMMA) and dioctadecyldimethylammonium bromide (DODAB), cetyltrimethylammonium bromide (CTAB), or tetrapropylammonium bromide (TPAB) were characterized by determination of wettability, ellipsometry, atomic force microscopy, active compounds diffusion to water, X-ray photoelectron spectroscopy (XPS) with determination of atomic composition on the films surface, and biocidal activity against Pseudomonas aeruginosa or Staphylococcus aureus. QAC mobility in the films increased from DODAB to CTAB to TPAB. Diffusion and optimal hydrophobic-hydrophilic balance imparted the highest bioactivity to CTAB. DODAB sustained immobilization at the film surface killed bacteria upon contact. TPAB ability to diffuse was useless because of its unfavorable hydrophobic-hydrophilic balance for bioactivity.

  13. (Accumulation of methyl-deficient rat liver messenger ribonucleic acid on ethionine administration). Progress report. [Methyltransferase activity in Ehrlich ascites tumor cells and effects of phorbol ester on methyltransferase activity

    SciTech Connect

    Borek, E.

    1980-01-01

    Enzyme fractions were isolated from Ehrlich ascites cells which introduced methyl groups into methyl deficient rat liver mRNA and unmethylated vaccinia mRNA. The methyl groups were incorporated at the 5' end into cap 1 structures by the viral enzyme, whereas both cap 0 and cap 1 structures were formed by the Ehrlich ascites cell enzymes. Preliminary results indicate the presence of adenine N/sup 6/-methyltransferase activity in Ehrlich ascites cells. These results indicate that mRNA deficient in 5'-cap methylation and in internal methylation of adenine accumulated in rats on exposure to ethionine. The methyl-deficient mRNA isolated from the liver of ethionine-fed rats differed in its translational properties from mRNA isolated from control animals. Preliminary experiments indicate that single topical application of 17n moles of TPA to mouse skin altered tRNA methyltransferases. The extent of methylation was increased over 2-fold in mouse skin treated with TPA for 48 hours. These changes have been observed as early as 12 hours following TPA treatment. In contrast, the application of initiating dose of DMBA had no effect on these enzymes. It should be emphasized that the changes in tRNA methyltransferases produced by TPA are not merely an increase of the concentration of the enzyme, rather that they represent alterations of specificity of a battery of enzymes. In turn the change in enzyme specificity can produce alterations in the structure of tRNA. (ERB)

  14. Epigallocatechin-3-gallate potently inhibits the in vitro activity of hydroxy-3-methyl-glutaryl-CoA reductase[S

    PubMed Central

    Cuccioloni, Massimiliano; Mozzicafreddo, Matteo; Spina, Michele; Tran, Chi Nhan; Falconi, Maurizio; Eleuteri, Anna Maria; Angeletti, Mauro

    2011-01-01

    Hydroxy-3-methyl-glutaryl-CoA reductase (HMGR) is the rate-controlling enzyme of cholesterol synthesis, and owing to its biological and pharmacological relevance, researchers have investigated several compounds capable of modulating its activity with the hope of developing new hypocholesterolemic drugs. In particular, polyphenol-rich extracts were extensively tested for their cholesterol-lowering effect as alternatives, or adjuvants, to the conventional statin therapies, but a full understanding of the mechanism of their action has yet to be reached. Our work reports on a detailed kinetic and equilibrium study on the modulation of HMGR by the most-abundant catechin in green tea, epigallocatechin-3-gallate (EGCG). Using a concerted approach involving spectrophotometric, optical biosensor, and chromatographic analyses, molecular docking, and site-directed mutagenesis on the cofactor site of HMGR, we have demonstrated that EGCG potently inhibits the in vitro activity of HMGR (Ki in the nanomolar range) by competitively binding to the cofactor site of the reductase. Finally, we evaluated the effect of combined EGCG-statin administration. PMID:21357570

  15. Long-term imipramine treatment increases N-methyl-d-aspartate receptor activity and expression via epigenetic mechanisms.

    PubMed

    Nghia, Nguyen An; Hirasawa, Takae; Kasai, Hirotake; Obata, Chie; Moriishi, Kohji; Mochizuki, Kazuki; Koizumi, Schuichi; Kubota, Takeo

    2015-04-05

    Imipramine, a major antidepressant, is known to inhibit reuptake of serotonin and norepinephrine, which contributes to recovery from major depressive disorder. It has recently been reported that acute imipramine treatment inhibits N-methyl-d-aspartate (NMDA) receptor activity. However, the mechanisms underlying long-term effects of imipramine have not been identified. We tested these distinct effects in mouse cortical neurons and found that acute (30s) imipramine treatment decreased Ca(2+) influx through NMDA receptors, whereas long-term treatment (48h) increased Ca(2+) influx via the same receptors. Furthermore, long-term treatment increased NMDA receptor 2B (NR2B) subunit expression via epigenetic changes, including increased acetylation of histones H3K9 and H3K27 in the NR2B promoter and decreased activity of histone deacetylase 3 (HDAC3) and HDAC4. These results suggest that the long-term effects of imipramine on NMDA receptors are quite different from its acute effects. Furthermore, increased NR2B expression via epigenetic alterations might be a part of the mechanism responsible for this long-term effect.

  16. Fatty acid methyl ester (FAME) technology for monitoring biological foaming in activated sludge: full scale plant verification.

    PubMed

    Lee, J W; Cha, D K; Kim, I; Son, A; Ahn, K H

    2008-02-01

    Fatty acid methyl ester (FAME) technology was evaluated as a monitoring tool for quantification of Gordonia amarae in activated sludge systems. The fatty acid, 19:1 alcohol, which was identified as a unique fatty acid in G. amarae was not only confirmed to be present in foaming plant samples, but the quantity of the signature peak correlated closely with the degree of foaming. Foaming potential experiment provided a range of critical foaming levels that corresponded to G. amarae population. This range of critical Gordonia levels was correlated to the threshold signature FAME amount. Six full-scale wastewater treatment plants were selected based on a survey to participate in our full-scale study to evaluate the potential application of the FAME technique as the Gordonia monitoring tool. Greater amounts of signature FAME were extracted from the mixed liquor samples obtained from treatment plants experiencing Gordonia foaming problems. The amounts of signature FAME correlated well with the conventional filamentous counting technique. These results demonstrated that the relative abundance of the signature FAMEs can be used to quantitatively monitor the abundance of foam-causing microorganism in activated sludge.

  17. Methyl methacrylate-induced changes in CNS (central nervous system) activity. 1 March 1978-28 February 1980

    SciTech Connect

    Innes, D.L.

    1980-01-01

    Experiments were performed to determine if methyl-methacrylate (MMA) monomer vapor in air caused central nervous system (CNS) changes in exposed rats. Rats were exposed to 400 parts per million (ppm) MMA vapor for 60 minutes. The only significant changes occurred in the lateral hypothalamic and ventral hippocampal nuclei. Several substudies suggested that the changes in the hippocampal neuronal firing rates were related to the perception of the MMA odor and dependent on an intact nervous connection to the receptors in the nose. In a subchronic study no consistent long term changes in neuronal activity were detected. However, a decrease in neuronal activity was detected during the first week of exposure. In another study, the exposure levels of MMA ranged from 50 to 800 ppm. The lateral hypothalamic and ventral hippocampal nuclei responded as before, but not at the 50 ppm level. The author concludes that the threshold exposure concentration for the observed effects are the same as or slightly less than the current threshold limit value for MMA vapor in the workplace.

  18. Observations of hysteresis in solar cycle variations among seven solar activity indicators

    NASA Technical Reports Server (NTRS)

    Bachmann, Kurt T.; White, Oran R.

    1994-01-01

    We show that smoothed time series of 7 indices of solar activity exhibit significant solar cycle dependent differences in their relative variations during the past 20 years. In some cases these observed hysteresis patterns start to repeat over more than one solar cycle, giving evidence that this is a normal feature of solar variability. Among the indices we study, we find that the hysteresis effects are approximately simple phase shifts, and we quantify these phase shifts in terms of lag times behind the leading index, the International Sunspot Number. Our measured lag times range from less than one month to greater than four months and can be much larger than lag times estimated from short-term variations of these same activity indices during the emergence and decay of major active regions. We argue that hysteresis represents a real delay in the onset and decline of solar activity and is an important clue in the search for physical processes responsible for changing solar emission at various wavelengths.

  19. Nuclear cathepsin L activity is required for cell cycle progression of colorectal carcinoma cells.

    PubMed

    Tamhane, Tripti; Lllukkumbura, Rukshala; Lu, Shiying; Maelandsmo, Gunhild M; Haugen, Mads H; Brix, Klaudia

    2016-03-01

    Prominent tasks of cysteine cathepsins involve endo-lysosomal proteolysis and turnover of extracellular matrix constituents or plasma membrane proteins for maintenance of intestinal homeostasis. Here we report on enhanced levels and altered subcellular localization of distinct cysteine cathepsins in adenocarcinoma tissue in comparison to adjacent normal colon. Immunofluorescence and immunoblotting investigations revealed the presence of cathepsin L in the nuclear compartment in addition to its expected endo-lysosomal localization in colorectal carcinoma cells. Cathepsin L was represented as the full-length protein in the nuclei of HCT116 cells from which stefin B, a potent cathepsin L inhibitor, was absent. Fluorescence activated cell sorting analyses with synchronized cell cultures revealed deceleration of cell cycle progression of HCT116 cells upon inhibition of cathepsin L activity, while expression of cathepsin L-enhanced green fluorescent protein chimeras accelerated S-phase entry. We conclude that the activity of cathepsin L is high in the nucleus of colorectal carcinoma cells because of lacking stefin B inhibitory activity. Furthermore, we hypothesize that nuclear cathepsin L accelerates cell cycle progression of HCT116 cells thereby supporting the notion that cysteine cathepsins may play significant roles in carcinogenesis due to deregulated trafficking.

  20. Effect of sprouting and light cycle on antioxidant activity of Brassica oleracea varieties.

    PubMed

    Vale, Ana Paula; Cidade, Honorina; Pinto, Madalena; Oliveira, M Beatriz P P

    2014-12-15

    The antioxidant activity of sprouts from four Brassica oleracea varieties was evaluated using "in vitro" methods (total phenolic and flavonoid content; radical scavenging assays: DPPH, hydroxyl and peroxyl; and Ferrous Ion-chelating Ability Assay). Light cycles and sprouting influenced the potential antioxidant activity of sprouts and significant differences were observed between varieties. Generally, antioxidant activity decreased with sprouting and increased in the presence of light, whose discriminant effect was highly significant (P<0.001). Red cabbage sprouts produced under light cycles showed the highest antioxidant activity (57.11 μg mL(-1) Ferrous Ion-chelating Ability, 221.46 μg mL(-1) Hydroxyl radical scavenging, 279.02 μg mL(-1) Peroxyl radical scavenging). Among the traditional Portuguese brassica varieties, Penca cabbage sprouts produced under light presented higher antioxidant capacity, and also higher phenolic and flavonoid content (54.04 mg GAEg(-1) d.w. extract and 21.33 QEg(-1) d.w. extract, respectively) than Galega kale. The phenolic content of Brassica sprouts had a significant contribution to the antioxidant capacity.

  1. Dynamo-based scheme for forecasting the magnitude of solar activity cycles

    NASA Technical Reports Server (NTRS)

    Layden, A. C.; Fox, P. A.; Howard, J. M.; Sarajedini, A.; Schatten, K. H.

    1991-01-01

    This paper presents a general framework for forecasting the smoothed maximum level of solar activity in a given cycle, based on a simple understanding of the solar dynamo. This type of forecasting requires knowledge of the sun's polar magnetic field strength at the preceding activity minimum. Because direct measurements of this quantity are difficult to obtain, the quality of a number of proxy indicators already used by other authors is evaluated, which are physically related to the sun's polar field. These indicators are subjected to a rigorous statistical analysis, and the analysis technique for each indicator is specified in detail in order to simplify and systematize reanalysis for future use. It is found that several of these proxies are in fact poorly correlated or uncorrelated with solar activity, and thus are of little value for predicting activity maxima. Also presented is a scheme in which the predictions of the individual proxies are combined via an appropriately weighted mean to produce a compound prediction. The scheme is then applied to the current cycle 22, and a maximum smoothed international sunspot number of 171 + or - 26 is estimated.

  2. Arginine methylation of USP9X promotes its interaction with TDRD3 and its anti-apoptotic activities in breast cancer cells

    PubMed Central

    Narayanan, Nithya; Wang, Zhihao; Li, Ling; Yang, Yanzhong

    2017-01-01

    The Tudor domain-containing proteins are characterized by their specific interactions with methylated protein motifs, including methyl-arginines and methyl-lysines. The Tudor domain-containing protein 3 (TDRD3) is one of the major methyl-arginine effector molecules that recognizes methylated arginine residues on histones and the C-terminal domain of RNA polymerase II, and activates transcription. However, majority of the cellular TDRD3 localizes to the cytoplasm and its functions there are still elusive. Here, we have identified ubiquitin-specific protease 9 X-linked (USP9X) as a TDRD3-interacting protein by GST (glutathione S-transferase) pull-down and co-immunoprecipitation. Detailed characterization suggests that the interaction between TDRD3 and USP9X is mediated through the Tudor domain of TDRD3 and the arginine methylation of USP9X. This interaction plays a critical role in TDRD3 protein stability, as knockdown of USP9X expression leads to increased TDRD3 ubiquitination. We also found that USP9X co-localizes with TDRD3 in cytoplasmic stress granules and this localization is diminished in Tdrd3-null mouse embryonic fibroblast cells, suggesting that TDRD3 is essential for USP9X stress granule localization. Furthermore, we found that one of the USP9X de-ubiquitination targets, myeloid cell leukemia protein 1, is regulated by TDRD3, indicating that TDRD3 potentially regulates USP9X de-ubiquitinase activity. Finally, we show that knockdown of TDRD3 expression sensitizes breast cancer cells to chemotherapeutic drug-induced apoptosis, likely due to its regulation of USP9X. This study provides a novel candidate strategy for targeting apoptosis pathways in cancer therapy. PMID:28101374

  3. Role of aerosols in modulating cloud properties during active-break cycle of Indian summer monsoon

    NASA Astrophysics Data System (ADS)

    Bhattacharya, A.; Chakraborty, A.; Venugopal, V.

    2016-11-01

    In this study, the weather research and forecast model coupled with chemistry (WRF-Chem), is used to understand the impact of aerosol-cloud interaction during the active-break cycles of the Indian summer monsoon. Two sets of simulations are performed, one with a fixed aerosol concentration (ConstantAero) and the other with an observation-based prescription of the rate of change of aerosol concentration as a function of precipitation (VaryingAero). This prescription is derived based on satellite-retrieved daily rainrate and concurrent observations of aerosol optical depth from aerosol robotic network. The proposed modification is necessitated by the lack of realistic emission estimates over the Indian region as well as the presence of inherent biases in monsoon simulation in WRF-Chem. In the VaryingAero simulation, unlike in the ConstantAero run, we find that the break-to-active monsoon phase has more cloud liquid water (CLW) and less rain efficiency than in the active-to-break phase. This is primarily due to the indirect effect of increased aerosol loading in the break phase. This result is in accordance with the observed behaviour of CLW estimtes from microwave imager (TRMM 2A12) and radar reflectivity (TRMM precipitation radar). We also find that the proposed interactive aerosol loading results in higher spatial variability in CLW and enhances the likelihood of increased cloud cover via formation of larger clouds. The modification also alters the diurnal cycle of clouds in break and break-to-active phases as compared to other phases due to aerosol loading, with a stronger diurnal cycle of upper level clouds in these phases in the VaryingAero model as compared to ConstantAero model.

  4. Spectral analysis of auroral geomagnetic activity during various solar cycles between 1960 and 2014

    NASA Astrophysics Data System (ADS)

    Kotzé, Pieter Benjamin

    2016-12-01

    In this paper we use wavelets and Lomb-Scargle spectral analysis techniques to investigate the changing pattern of the different harmonics of the 27-day solar rotation period of the AE (auroral electrojet) index during various phases of different solar cycles between 1960 and 2014. Previous investigations have revealed that the solar minimum of cycles 23-24 exhibited strong 13.5- and 9.0-day recurrence in geomagnetic data in comparison to the usual dominant 27.0-day synodic solar rotation period. Daily mean AE indices are utilized to show how several harmonics of the 27-day recurrent period change during every solar cycle subject to a 95 % confidence rule by performing a wavelet analysis of each individual year's AE indices. Results show that particularly during the solar minimum of 23-24 during 2008 the 27-day period is no longer detectable above the 95 % confidence level. During this interval geomagnetic activity is now dominated by the second (13.5-day) and third (9.0-day) harmonics. A Pearson correlation analysis between AE and various spherical harmonic coefficients describing the solar magnetic field during each Carrington rotation period confirms that the solar dynamo has been dominated by an unusual combination of sectorial harmonic structure during 23-24, which can be responsible for the observed anomalously low solar activity. These findings clearly show that, during the unusual low-activity interval of 2008, auroral geomagnetic activity was predominantly driven by high-speed solar wind streams originating from multiple low-latitude coronal holes distributed at regular solar longitude intervals.

  5. Enriching step-based product information models to support product life-cycle activities

    NASA Astrophysics Data System (ADS)

    Sarigecili, Mehmet Ilteris

    The representation and management of product information in its life-cycle requires standardized data exchange protocols. Standard for Exchange of Product Model Data (STEP) is such a standard that has been used widely by the industries. Even though STEP-based product models are well defined and syntactically correct, populating product data according to these models is not easy because they are too big and disorganized. Data exchange specifications (DEXs) and templates provide re-organized information models required in data exchange of specific activities for various businesses. DEXs show us it would be possible to organize STEP-based product models in order to support different engineering activities at various stages of product life-cycle. In this study, STEP-based models are enriched and organized to support two engineering activities: materials information declaration and tolerance analysis. Due to new environmental regulations, the substance and materials information in products have to be screened closely by manufacturing industries. This requires a fast, unambiguous and complete product information exchange between the members of a supply chain. Tolerance analysis activity, on the other hand, is used to verify the functional requirements of an assembly considering the worst case (i.e., maximum and minimum) conditions for the part/assembly dimensions. Another issue with STEP-based product models is that the semantics of product data are represented implicitly. Hence, it is difficult to interpret the semantics of data for different product life-cycle phases for various application domains. OntoSTEP, developed at NIST, provides semantically enriched product models in OWL. In this thesis, we would like to present how to interpret the GD & T specifications in STEP for tolerance analysis by utilizing OntoSTEP.

  6. North-south asymmetry in small and large sunspot group activity and violation of even-odd solar cycle rule

    NASA Astrophysics Data System (ADS)

    Javaraiah, J.

    2016-07-01

    According to Gnevyshev-Ohl (G-O) rule an odd-numbered cycle is stronger than its preceding even-numbered cycle. In the modern time the cycle pair (22, 23) violated this rule. By using the combined Greenwich Photoheliographic Results (GPR) and Solar Optical Observing Network (SOON) sunspot group data during the period 1874-2015, and Debrecen Photoheliographic Data (DPD) of sunspot groups during the period 1974-2015, here we have found that the solar cycle pair (22, 23) violated the G-O rule because, besides during cycle 23 a large deficiency of small sunspot groups in both the northern and the southern hemispheres, during cycle 22 a large abundance of small sunspot groups in the southern hemisphere. In the case of large and small sunspot groups the cycle pair (22, 23) violated the G-O rule in the northern and southern hemispheres, respectively, suggesting the north-south asymmetry in solar activity has a significant contribution in the violation of G-O rule. The amplitude of solar cycle 24 is smaller than that of solar cycle 23. However, Coronal Mass Ejections (CMEs) rate in the rising phases of the cycles 23 and 24 are almost same (even slightly large in cycle 24). From both the SOON and the DPD sunspot group data here we have also found that on the average the ratio of the number (counts) of large sunspot groups to the number of small sunspot groups is larger in the rising phase of cycle 24 than that in the corresponding phase of cycle 23. We suggest this could be a potential reason for the aforesaid discrepancy in the CME rates during the rising phases of cycles 23 and 24. These results have significant implication on solar cycle mechanism.

  7. A simulation study of inorganic sulfur cycling in the water level fluctuation zone of the Three Gorges Reservoir, China and the implications for mercury methylation.

    PubMed

    Liu, Jiang; Jiang, Tao; Huang, Rong; Wang, Dingyong; Zhang, Jinzhong; Qian, Sheng; Yin, Deliang; Chen, Hong

    2017-01-01

    The water level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) in China experiences a drying and wetting rotation every year, and the water level induced redox variation may influence inorganic sulfur speciation and mercury methylation. In this work, a simulative flooding and drying experiment and a sulfate added flooding experiment were conducted to study this topic. The results showed that sulfate was reduced from the 10th d during the flooding period based on the detected sulfide in water and the increased elemental sulfur (S(0)) in sediment. Sulfate reduction and sulfide re-oxidation led to the increase of S(0) contents with the maximal values of 1.86 and 0.46 mg kg(-1) during the flooding and drying period, respectively. Methylmercury (MeHg) content in sediment displayed a rising trend (0.16-0.28 μg kg(-1)) in the first 40 d during the flooding period, and then declined from 0.28 to 0.15 μg kg(-1). A positive correlation between MeHg content and S(0) content in soil (r = 0.53, p < 0.05) was found during the flooding period, and a positive but not significant correlation between the percent of MeHg in THg (%MeHg) and S(0) content (r = 0.85, p = 0.08). In sulfate added flooding simulation, MeHg content in sediment did not increase with the sulfate concentration increasing. The increased pyrite in high-sulfate treatment may fix mercury through adsorption process. This study demonstrated that inorganic sulfur species especially S(0) and chromium reducible sulfur (CRS) play an important role on mercury methylation in the WLFZ of the TGR.

  8. Enzymatic synthesis of theanine from glutamic acid γ-methyl ester and ethylamine by immobilized Escherichia coli cells with γ-glutamyltranspeptidase activity.

    PubMed

    Zhang, Fei; Zheng, Qing-Zhong; Jiao, Qing-Cai; Liu, Jun-Zhong; Zhao, Gen-Hai

    2010-11-01

    Theanine (γ-glutamylethylamide) is the main amino acid component in green tea. The demand for theanine in the food and pharmaceutical industries continues to increase because of its special flavour and multiple physiological effects. In this research, an improved method for enzymatic theanine synthesis is reported. An economical substrate, glutamic acid γ-methyl ester, was used in the synthesis catalyzed by immobilized Escherichia coli cells with γ-glutamyltranspeptidase (GGT) activity. The results show that GGT activity with glutamic acid γ-methyl ester as substrate was about 1.2-folds higher than that with glutamine as substrate. Reaction conditions were optimized by using 300 mmol/l glutamic acid γ-methyl ester, 3,000 mmol/l ethylamine, and 0.1 g/ml of immobilized GGT cells at pH 10 and 50°C. Under these conditions, the immobilized cells were continuously used ten times, yielding an average glutamic acid γ-methyl ester to theanine conversion rate of 69.3%. Bead activity did not change significantly the first six times they were used, and the average conversion rate during the first six instances was 87.2%. The immobilized cells exhibited favourable operational stability.

  9. The potent antioxidant activity of the vitamin K cycle in microsomal lipid peroxidation.

    PubMed

    Vervoort, L M; Ronden, J E; Thijssen, H H

    1997-10-15

    In the vitamin K cycle, vitamin K-hydroquinone, the active cofactor for gamma-glutamylcarboxylase, is continuously regenerated. The successive pathways contain oxidation of the hydroquinone to the epoxide, followed by reduction to the quinone and reduction to the hydroquinone. Vitamin K-hydroquinone is a potent radical scavenging species (Mukai et al., J Biol Chem 267: 22277-22281, 1992). We tested the potential antioxidant activity of the vitamin K cycle in lipid peroxidation reactions (thiobarbituric acid reactive substances, TBARS) in rat liver microsomes. As prooxidant we used Fe2+/ascorbate, NADPH-Fe3+/ATP, and NADPH/CCl4. Vitamin K (< or = 50 microM) on its own did not influence the formation of TBARS. In combination with 1 mM dithiothreitol (DTT), the reductive cofactor for the microsomal enzyme vitamin K epoxide reductase, vitamin K suppressed lipid peroxidation with a concentration that blocked the maximal response by 50% (IC50) of ca. 0.2 microM. Vitamin K1 (phylloquinone) and vitamin K2 (menaquinone-4) were equally active. Warfarin (5 microM) and chloro-vitamin K (50 microM), inhibitors of vitamin K epoxide reductase and gamma-glutamylcarboxylase, respectively, were able to completely abolish the antioxidant effect. Lipid peroxidation was inversely related to the amount of vitamin K hydroquinone in the reaction. Vitamin K epoxide reductase seemed sensitive to lipid peroxidation, with half of the activity being lost within 10 min during oxidation with NADPH/CCl4. The inactivation could be attenuated by antioxidants such as vitamin E, reduced glutathione, and menadione and also by a K vitamin in combination with DTT, but not by superoxide dismutase and catalase. The results show that the vitamin K cycle could act as a potent antioxidant, that the active species in all probability is vitamin K-hydroquinone, and that the primary reaction product is the semiquinone. The results also show that the reaction product is processed in the vitamin K cycle to

  10. Conserved DNA methylation in Gadd45a(-/-) mice.

    PubMed

    Engel, Nora; Tront, Jennifer S; Erinle, Toyin; Nguyen, Nghi; Latham, Keith E; Sapienza, Carmen; Hoffman, Barbara; Liebermann, Dan A

    2009-02-16

    Gadd45a (growth arrest and DNA-damage-inducible protein 45 alpha) plays a pivotal role in cellular stress responses and is implicated in DNA repair, cell cycle arrest and apoptosis.(1) Recently, it was proposed that GADD45A is a key regulator of active DNA demethylation by way of its role in DNA repair.(2) Barreto et al. reported that Gadd45a overexpression activated transcription from methylation-silenced reporter plasmids and promoted global DNA demethylation. siRNA-mediated knockdown of Gadd45a levels resulted in increased levels of DNA methylation at specific endogenous loci. Based on these exciting results, Gadd45a(-/-) mice might be predicted to have a hypermethylation phenotype. We report here that neither global nor locus-specific methylation is increased in Gadd45a(-/-) mice.

  11. Murine T cell activation is regulated by surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide)

    SciTech Connect

    Warford, Jordan; Doucette, Carolyn D.; Hoskin, David W.; Easton, Alexander S.

    2014-01-10

    Highlights: •Surfen is the first inhibitor of glycosaminoglycan function to be studied in murine T cells. •Surfen reduces T cell proliferation stimulated in vitro and in vivo. •Surfen reduces CD25 expression in T cells activated in vivo but not in vitro. •Surfen increases T cell proliferation when T cell receptor activation is bypassed. •Surfen’s effects are blocked by co-administration of heparin sulfate. -- Abstract: Surfen (bis-2-methyl-4-amino-quinolyl-6-carbamide) binds to glycosaminoglycans (GAGs) and has been shown to influence their function, and the function of proteoglycans (complexes of GAGs linked to a core protein). T cells synthesize, secrete and express GAGs and proteoglycans which are involved in several aspects of T cell function. However, there are as yet no studies on the effect of GAG-binding agents such as surfen on T cell function. In this study, surfen was found to influence murine T cell activation. Doses between 2.5 and 20 μM produced a graduated reduction in the proliferation of T cells activated with anti-CD3/CD28 antibody-coated T cell expander beads. Surfen (20 mg/kg) was also administered to mice treated with anti-CD3 antibody to activate T cells in vivo. Lymphocytes from surfen-treated mice also showed reduced proliferation and lymph node cell counts were reduced. Surfen reduced labeling with a cell viability marker (7-ADD) but to a much lower extent than its effect on proliferation. Surfen also reduced CD25 (the α-subunit of the interleukin (IL)-2 receptor) expression with no effect on CD69 expression in T cells treated in vivo but not in vitro. When receptor activation was bypassed by treating T cells in vitro with phorbyl myristate acetate (10 ng/ml) and ionomycin (100 ng/ml), surfen treatment either increased proliferation (10 μM) or had no effect (2.5, 5 and 20 μM). In vitro treatment of T cells with surfen had no effect on IL-2 or interferon-γ synthesis and did not alter proliferation of the IL-2 dependent cell

  12. Cell-cycle-dependent regulation of Ca2+-activated K+ channel in Jurkat T-lymphocyte.

    PubMed

    Morimoto, Takashi; Ohya, Susumu; Hayashi, Hidetoshi; Onozaki, Kikuo; Imaizumi, Yuji

    2007-05-01

    Small-conductance Ca2+-activated K+ (SK2) channel plays an important role in the activation of Jurkat T-lymphocytes by maintaining electrical gradients for the sustained Ca2+ influx. Apamin-sensitive K+ current was significantly decreased with cell-cycle progression from G0/G1 into G2/M phases, and protein expression of SK2 channels showed parallel down-regulation, with its highest expression at early G0/G1 phase. In the G0/G1 phase, the apamin-sensitive component of thapsigargin-induced Ca2+ influx was significantly larger than that in the G2/M phase. These observations suggest that SK2-channel activation may largely contribute to the sustained Ca2+ influx in the G0/G1 phase in comparison of that in the G2/M phase in Jurkat T-lymphocytes.

  13. Cross talk between cell death and cell cycle progression: BCL-2 regulates NFAT-mediated activation.

    PubMed Central

    Linette, G P; Li, Y; Roth, K; Korsmeyer, S J

    1996-01-01

    BCL-2-deficient T cells demonstrate accelerated cell cycle progression and increased apoptosis following activation. Increasing the levels of BCL-2 retarded the G0-->S transition, sustained the levels of cyclin-dependent kinase inhibitor p27Kip1, and repressed postactivation death. Proximal signal transduction events and immediate early gene transcription were unaffected. However, the transcription and synthesis of interleukin 2 and other delayed early cytokines were markedly attenuated by BCL-2. In contrast, a cysteine protease inhibitor that also blocks apoptosis had no substantial affect upon cytokine production. InterleUkin 2 expression requires several transcription factors of which nuclear translocation of NFAT (nuclear factor of activated T cells) and NFAT-mediated transactivation were impaired by BCL-2. Thus, select genetic aberrations in the apoptotic pathway reveal a cell autonomous coregulation of activation. Images Fig. 3 Fig. 4 Fig. 7 PMID:8790367

  14. CG methylation.

    PubMed

    Vinson, Charles; Chatterjee, Raghunath

    2012-12-01

    A striking feature of mammalian genomes is the paucity of the CG dinucleotide. There are approximately 20,000 regions termed CpG islands where CGs cluster. This represents 5% of all CGs and 1% of the genome. CpG islands are typically unmethylated and are often promoters for housekeeping genes. The remaining 95% of CG dinucleotides are disposed throughout 99% of the genome and are typically methylated and found in half of all promoters. CG methylation facilitates binding of the C/EBP family of transcription factors, proteins critical for differentiation of many tissues. This allows these proteins to localize in the methylated CG poor regions of the genome where they may produce advantageous changes in gene expression at nearby or more distant regions of the genome. In this review, our growing understanding of the consequences of CG methylation will be surveyed.

  15. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYL METHACRYLATE ( CAS No . 80 - 62 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) January 1998 U.S . Environmental Protection Agency Washington , DC TABLE OF CONTENTS DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . .

  16. Placental insufficiency decreases cell cycle activity and terminal maturation in fetal sheep cardiomyocytes

    PubMed Central

    Louey, Samantha; Jonker, Sonnet S; Giraud, George D; Thornburg, Kent L

    2007-01-01

    Umbilicoplacental embolization (UPE) in sheep has been used to investigate the effects of placental insufficiency on fetal development. However, its specific effects on the heart have been little studied. The aim of this study was to determine the effects of placental insufficiency, induced by UPE, on cardiomyocyte size, maturation and proliferation. Instrumented fetal sheep underwent UPE for either 10 or 20 days. Hearts were collected at 125 ± 1 days (10 day group) or 136 ± 1 days (20 day group) of gestation (term ∼145 days). Cell size, maturational state (as measured by the proportion of binucleated myocytes) and cell cycle activity (as measured by positive staining of cells for Ki-67) were determined in dissociated cardiomyocytes. UPE fetuses were hypoxaemic, but mean arterial pressures were not different from controls. UPE fetuses were lighter than control fetuses (10 days: −21%, P < 0.05; 20 days: −27%, P < 0.01) and had smaller hearts, but heart weight was appropriate for body weight. Neither lengths nor widths were different between control and UPE cardiomyocytes at either age. Ten days of UPE did not significantly alter the proportion of binucleated myocytes or cell cycle activity in either ventricle. However, 20 days of UPE reduced cell cycle activity in both ventricles by ∼70% (P < 0.05); the proportion of binucleated myocytes was also lower in UPE fetuses at this age (left ventricle: 31.1 ± 12.0 versus 46.0 ± 6.6%, P < 0.05; right ventricle: 29.4 ± 12.3 versus 46.3 ± 5.3%, P < 0.05). It is concluded that in the absence of fetal arterial hypertension, placental insufficiency is associated with substantially depressed growth of the heart through suppressed proliferation and maturation of cardiomyocytes. PMID:17234700

  17. ICBP90, a novel methyl K9 H3 binding protein linking protein ubiquitination with heterochromatin formation.

    PubMed

    Karagianni, Panagiota; Amazit, Larbi; Qin, Jun; Wong, Jiemin

    2008-01-01

    Methylation of histone H3 on lysine 9 is critical for diverse biological processes including transcriptional repression, heterochromatin formation, and X inactivation. The biological effects of histone methylation are thought to be mediated by effector proteins that recognize and bind to specific patterns of methylation. Using an unbiased in vitro biochemical approach, we have identified ICBP90, a transcription and cell cycle regulator, as a novel methyl K9 H3-specific binding protein. ICBP90 and its murine homologue Np95 are enriched in pericentric heterochromatin of interphase nuclei, and this localization is dependent on H3K9 methylation. Specific binding of ICBP90 to methyl K9 H3 depends on two functional domains, a PHD (plant homeodomain) finger that defines the binding specificity and an SRA (SET- and RING-associated) domain that promotes binding activity. Furthermore, we present evidence that ICBP90 is required for proper heterochromatin formation in mammalian cells.

  18. Abundances and potential activities of nitrogen cycling microbial communities along a chronosequence of a glacier forefield

    PubMed Central

    Brankatschk, Robert; Töwe, Stefanie; Kleineidam, Kristina; Schloter, Michael; Zeyer, Josef

    2011-01-01

    Glacier forefields are ideal ecosystems to study the development of nutrient cycles as well as single turnover processes during soil development. In this study, we examined the ecology of the microbial nitrogen (N) cycle in bulk soil samples from a chronosequence of the Damma glacier, Switzerland. Major processes of the N cycle were reconstructed on the genetic as well as the potential enzyme activity level at sites of the chronosequence that have been ice-free for 10, 50, 70, 120 and 2000 years. In our study, we focused on N fixation, mineralization (chitinolysis and proteolysis), nitrification and denitrification. Our results suggest that mineralization, mainly the decomposition of deposited organic material, was the main driver for N turnover in initial soils, that is, ice-free for 10 years. Transient soils being ice-free for 50 and 70 years were characterized by a high abundance of N fixing microorganisms. In developed soils, ice-free for 120 and 2000 years, significant rates of nitrification and denitrification were measured. Surprisingly, copy numbers of the respective functional genes encoding the corresponding enzymes were already high in the initial phase of soil development. This clearly indicates that the genetic potential is not the driver for certain functional traits in the initial phase of soil formation but rather a well-balanced expression of the respective genes coding for selected functions. PMID:21124490

  19. Structure-activity relationship between carboxylic acids and T cell cycle blockade.

    PubMed

    Gilbert, Kathleen M; DeLoose, Annick; Valentine, Jimmie L; Fifer, E Kim

    2006-04-04

    This study was designed to examine the potential structure-activity relationship between carboxylic acids, histone acetylation and T cell cycle blockade. Toward this goal a series of structural homologues of the short-chain carboxylic acid n-butyrate were studied for their ability to block the IL-2-stimulated proliferation of cloned CD4+ T cells. The carboxylic acids were also tested for their ability to inhibit histone deacetylation. In addition, Western blotting was used to examine the relative capacity of the carboxlic acids to upregulate the cyclin kinase-dependent inhibitor p21cip1 in T cells. As shown earlier n-butyrate effectively inhibited histone deacetylation. The increased acetylation induced by n-butyrate was associated with the upregulation of the cyclin-dependent kinase inhibitor p21cip1 and the cell cycle blockade of CD4+ T cells. Of the other carboxylic acids studied, the short chain acids, C3-C5, without branching were the best inhibitors of histone deacetylase. This inhibition correlated with increased expression of the cell cycle blocker p21cip1, and the associated suppression of CD4+ T cell proliferation. The branched-chain carboxylic acids tested were ineffective in all the assays. These results underline the relationship between the ability of a carboxylic acid to inhibit histone deacetylation, and their ability to block T cell proliferation, and suggests that branching inhibits these effects.

  20. Principal Component Analysis of Solar Background and Sunspot Magnetic Field in cycles 21-24 and its implications for the solar activity prediction in cycles 25-27

    NASA Astrophysics Data System (ADS)

    Zharkova, Valentina; Popova, Helen; Zharkov, Sergei; Shepherd, Simon

    Principle component analysis (PCA) of the solar background magnetic field (SBMF) measured from Wilcox Solar Observatory (WSO) and sunspot magnetic field (SMF) measured by SOHO/MDI magnetograms reveals the two principal components (PCs) of waves travelling in time. In addition, the independent components analysis helps to uncover 8 pairs of SBMF waves in latitudes: two large symmetric magnetic waves , which are the same for all cycles 21-23, and three pairs of asymmetric magnetic waves, which are unique for each cycle. In each pair the waves travel slightly off phase with different phase shift for each cycle and have a different number of equator crossings (Zharkova et al, 2012). These SBMF variations are assumed to be those of poloidal magnetic field traveling slightly off-phase from pole to pole which are caused by a joint action of dipole and quadruple magnetic sources in the Sun. The simulations with the two layer Parker's dynamo model with meridional circulation revealed that the dominant pair of PCs can be produced by a magnetic dipole accounting for the two main dynamo waves operating between the two magnetic poles. The further three pairs of the waves are unique to each cycle and associated with the multiple magnetic sources in the solar interior: with a quadruple symmetry in both layers for cycle 21, with quadruple magnetic sources in the upper layer and dipole sources in the inner layer for cycle 22 and with the quadruple magnetic sources in the inner layer and the dipole sources in the upper layer for cycle 23 (Popova et al, 2013). The PCs derived for all three cycles from SMBF were used as a training set for the magnetic wave prediction for the cycles 24-27 by using Hamiltonian approach (Shepherd and Zharkova, 2014) and verifying by the SBMF observations in the current cycle 24. The prediction results indicate that the solar activity is defined mainly by the solar background magnetic fields while the sunspots and their magnetic fields seem to be

  1. Impact of lung inflation cycle frequency on rat muscle and skin sympathetic activity recorded using suction electrodes

    PubMed Central

    Huang, Chunhua; Marina, Nephtali; Gilbey, Michael P.

    2009-01-01

    Microneurography has been used in humans to study sympathetic activity supplying targets within skeletal muscle and skin. Comparable animal studies are relatively few, probably due to the technical demands of traditional fibre picking techniques. Here we apply a simple suction electrode technique to record cutaneous (CVC) and muscle (MVC) vasoconstrictor activities and describe and investigate the basis of the frequency dependence of lung inflation related modulation. Hindlimb MVC and CVC activities were recorded concurrently. The magnitude of MVC and CVC activities at the lung inflation cycle frequency was significantly less at 2.0 Hz than at lung inflation cycle frequencies ≤ 1.0 Hz. As lung inflation cycle frequency was increased the coherence between lung inflation cycle or BP and MVC or CVC waveforms decreased. Consistent with the hypothesis that much of the coherence between lung inflation cycle and nerve activity waveforms is secondary to oscillating baroreceptor activity attributable to BP waves, partialization with the BP waveform significantly decreased the coherence between lung inflation cycle and nerve waveforms, and there was an absence of coherence between these waveforms following sinus and aortic denervation. Our data extend findings from other laboratories and establish the value of a suction electrode technique for recording MVC and CVC activities. Furthermore, our observations describe the rates of positive pressure ventilation that avoid strong and regular gating of sympathetic activity. PMID:19457723

  2. Effect of oral administration of sodium bicarbonate on surface EMG activity during repeated cycling sprints.

    PubMed

    Matsuura, Ryouta; Arimitsu, Takuma; Kimura, Takehide; Yunoki, Takahiro; Yano, Tokuo

    2007-11-01

    The purpose of this study was to determine the effect of oral administration of sodium bicarbonate (NaHCO3) on surface electromyogram (SEMG) activity from the vastus lateralis (VL) during repeated cycling sprints (RCS). Subjects performed two RCS tests (ten 10-s sprints) interspersed with both 30-s and 360-s recovery periods 1 h after oral administration of either NaHCO3 (RCSAlk) or CaCO3 (RCSPla) in a random counterbalanced order. Recovery periods of 360 s were set before the 5th and 9th sprints. The rate of decrease in plasma HCO3- concentration during RCS was significantly greater in RCSAlk than in RCSPla, but the rates of decline in blood pH during the two RCS tests were similar. There was no difference between change in plasma lactate concentration in RCSAlk and that in RCSPla. Performance during RCSAlk was similar to that during RCSPla. There were no differences in oxygen uptake immediately before each cycling sprint (preVO2) and in SEMG activity between RCSAlk and RCSPla. In conclusion, oral administration of NaHCO3 did not affect SEMG activity from the VL. This suggests that the muscle recruitment strategy during RCS is not determined by only intramuscular pH.

  3. Chemoenzymatic collective synthesis of optically active hydroxyl(methyl)tetrahydronaphthalene-based bioactive terpenoids.

    PubMed

    Batwal, Ramesh U; Argade, Narshinha P

    2015-12-14

    Starting from succinic anhydride and 2-methylanisole, a chemoenzymatic collective formal/total synthesis of several optically active tetrahydronaphthalene based bioactive natural products has been presented via advanced level common precursors; the natural product and antipode (-)/(+)-aristelegone B. Regioselective benzylic oxidations, stereoselective introduction of hydroxyl groups at the α-position of ketone moiety in syn-orientation, efficient enzymatic resolutions with high enantiomeric purity, stereoselective reductions, samarium iodide induced deoxygenations and tandem acylation-Wittig reactions without racemization and/or eliminative aromatization were the key features. An attempted diastereoselective synthesis of (±)-vallapin has also been described.

  4. Synthesis, photobiological activity and photoreactivity of methyl-thieno-8-azacoumarins, novel bioisosters of psoralen.

    PubMed

    Dalla Via, Lisa; Marciani Magno, Sebastiano; Rodighiero, Paolo; Gia, Ornella

    2002-05-06

    4,4'-dimethyl-thieno-8-azacoumarin (6) and 4,4',5'-trimethyl-thieno-8-azacoumarin (8) were synthesised. Their photobiological activity was tested on human tumour cell lines. Interestingly, for 6, a photocytotoxic ability higher in HL-60, comparable in HeLa cells, with respect to that of the well-known drug 8-methoxypsoralen (8-MOP), was demonstrated. The covalent photoaddition to DNA occurs by means of the molecular mechanism already demonstrated for furocoumarins. However, it is noteworthy that no skin phototoxicity appears.

  5. On the Relationship Between Solar Wind Speed, Geomagnetic Activity, and the Solar Cycle Using Annual Values

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2008-01-01

    The aa index can be decomposed into two separate components: the leading sporadic component due to solar activity as measured by sunspot number and the residual or recurrent component due to interplanetary disturbances, such as coronal holes. For the interval 1964-2006, a highly statistically important correlation (r = 0.749) is found between annual averages of the aa index and the solar wind speed (especially between the residual component of aa and the solar wind speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of solar wind speed are inferred to have also trended upward.

  6. Investigating the Potential of Activity Tracking App Data to Estimate Cycle Flows in Urban Areas

    NASA Astrophysics Data System (ADS)

    Haworth, J.

    2016-06-01

    Traffic congestion and its associated environmental effects pose a significant problem for large cities. Consequently, promoting and investing in green travel modes such as cycling is high on the agenda for many transport authorities. In order to target investment in cycling infrastructure and improve the experience of cyclists on the road, it is important to know where they are. Unfortunately, investment in intelligent transportation systems over the years has mainly focussed on monitoring vehicular traffic, and comparatively little is known about where cyclists are on a day to day basis. In London, for example, there are a limited number of automatic cycle counters installed on the network, which provide only part of the picture. These are supplemented by surveys that are carried out infrequently. Activity tracking apps on smart phones and GPS devices such as Strava have become very popular over recent years. Their intended use is to track physical activity and monitor training. However, many people routinely use such apps to record their daily commutes by bicycle. At the aggregate level, these data provide a potentially rich source of information about the movement and behaviour of cyclists. Before such data can be relied upon, however, it is necessary to examine their representativeness and understand their potential biases. In this study, the flows obtained from Strava Metro (SM) are compared with those obtained during the 2013 London Cycle Census (LCC). A set of linear regression models are constructed to predict LCC flows using SM flows along with a number of dummy variables including road type, hour of day, day of week and presence/absence of cycle lane. Cross-validation is used to test the fitted models on unseen LCC sites. SM flows are found to be a statistically significant (p<0.0001) predictor of total flows as measured by the LCC and the models yield R squared statistics of ~0.7 before considering spatio-temporal variation. The initial results indicate

  7. Recognition of enhancer element-specific histone methylation by TIP60 in transcriptional activation

    PubMed Central

    Jeong, Kwang Won; Kim, Kyunghwan; Situ, Alan Jialun; Ulmer, Tobias S.; An, Woojin; Stallcup, Michael R.

    2011-01-01

    Many coregulator proteins are recruited by DNA-bound transcription factors to remodel chromatin and activate transcription. However, mechanisms for coordinating actions of multiple coregulator proteins are poorly understood. We demonstrate that multiple protein-protein interactions by protein acetyltransferase TIP60 are required for estrogen-induced transcription of a subset of estrogen receptor (ER) α target genes in human cells. Estrogen-induced recruitment of TIP60 requires direct binding of TIP60 to ERα and the action of chromatin remodeling ATPase BRG1, leading to increased recruitment of histone methyltransferase MLL1 and increased monomethylation of histone H3 at Lys4. TIP60 recruitment also requires preferential binding of the TIP60 chromodomain to histone H3 containing monomethylated Lys4, which marks active and poised enhancer elements. After recruitment, TIP60 increases acetylation of histone H2A at Lys5. Thus, complex cooperation of TIP60 with ERα and other chromatin remodeling enzymes is required for estrogen-induced transcription. PMID:22081016

  8. Cycle Training Increased GLUT4 and Activation of mTOR in Fast Twitch Muscle Fibers

    PubMed Central

    Stuart, Charles A.; Howell, Mary E.A.; Baker, Jonathan D.; Dykes, Rhesa J.; Duffourc, Michelle M.; Ramsey, Michael W.; Stone, Michael H.

    2009-01-01

    Purpose To determine if cycle training of sedentary subjects would increase the expression of the principle muscle glucose transporters, six volunteers completed six weeks of progressively increasing intensity stationary cycle cycling. Methods In vastus lateralis muscle biopsies, changes in expression of GLUT1, GLUT4, GLUT5, and GLUT12 were compared using quantitative immunoblots with specific protein standards. Regulatory pathway components were evaluated by immunoblots of muscle homogenates and immunohistochemistry of microscopic sections. Results GLUT1 was unchanged, GLUT4 increased 66%, GLUT12 increased 104%, and GLUT5 decreased 72%. A mitochondrial marker (cytochrome c) and regulators of mitochondrial biogenesis (PGC-1α and phospho-AMPK) were unchanged, but the muscle hypertrophy pathway component, phospho-mTOR increased 83% after the exercise program. In baseline biopsies, GLUT4 by immunohistochemical techniques was 37% greater in Type I (slow twitch, red) muscle fibers, but the exercise training increased GLUT4 expression in Type II (fast twitch, white) fibers by 50%, achieving parity with the Type I fibers. Baseline phospho-mTOR expression was 50% higher in Type II fibers and increased more in Type II fibers (62%) with training, but also increased in Type I fibers (34%). Conclusion Progressive intensity stationary cycle training of previously sedentary subjects increased muscle insulin-responsive glucose transporters (GLUT4 and GLUT12) and decreased the fructose transporter (GLUT5). The increase in GLUT4 occurred primarily in Type II muscle fibers and this coincided with activation of the mTOR muscle hypertrophy pathway. There was little impact on Type I fiber GLUT4 expression and no evidence of change in mitochondrial biogenesis. PMID:20010125

  9. Enhanced adsorptive removal of methyl orange and methylene blue from aqueous solution by alkali-activated multiwalled carbon nanotubes.

    PubMed

    Ma, Jie; Yu, Fei; Zhou, Lu; Jin, Lu; Yang, Mingxuan; Luan, Jingshuai; Tang, Yuhang; Fan, Haibo; Yuan, Zhiwen; Chen, Junhong

    2012-11-01

    An alkali-acitvated method was explored to synthesize activated carbon nanotubes (CNTs-A) with a high specific surface area (SSA), and a large number of mesopores. The resulting CNTs-A were used as an adsorbent material for removal of anionic and cationic dyes in aqueous solutions. Experimental results indicated that CNTs-A have excellent adsorption capacity for methyl orange (149 mg/g) and methylene blue (399 mg/g). Alkali-activation treatment of CNTs increased the SSA and pore volume (PV), and introduced oxygen-containing functional groups on the surface of CNTs-A, which would be beneficial to improving the adsorption affinity of CNTs-A for removal of dyes. Kinetic regression results shown that the adsorption kinetic was more accurately represented by a pseudo second-order model. The overall adsorption process was jointly controlled by external mass transfer and intra-particle diffusion, and intra-particle diffusion played a dominant role. Freundlich isotherm model showed a better fit with adsorption data than Langmuir isotherm model. Adsorption interactions of dyes onto CNTs-A from aqueous solutions were investigated using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) method. The remarkable adsorption capacity of dye onto CNTs-A can be attributed to the multiple adsorption interaction mechanisms (hydrogen bonding, π-π electron-donor-acceptor interactions, electrostatic interactions, mesopore filling) on the CNTs-A. Results of this work are of great significance for environmental applications of activated CNTs as a promising adsorbent nanomaterial for organic pollutants from aqueous solutions.

  10. Adenosine A1 receptor activation modulates N-methyl-d-aspartate (NMDA) preconditioning phenotype in the brain.

    PubMed

    Constantino, Leandra C; Pamplona, Fabrício A; Matheus, Filipe C; Ludka, Fabiana K; Gomez-Soler, Maricel; Ciruela, Francisco; Boeck, Carina R; Prediger, Rui D; Tasca, Carla I

    2015-04-01

    N-methyl-d-aspartate (NMDA) preconditioning is induced by subtoxic doses of NMDA and it promotes a transient state of resistance against subsequent lethal insults. Interestingly, this mechanism of neuroprotection depends on adenosine A1 receptors (A1R), since blockade of A1R precludes this phenomenon. In this study we evaluated the consequences of NMDA preconditioning on the hippocampal A1R biology (i.e. expression, binding properties and functionality). Accordingly, we measured A1R expression in NMDA preconditioned mice (75mg/kg, i.p.; 24h) and showed that neither the total amount of receptor, nor the A1R levels in the synaptic fraction was altered. In addition, the A1R binding affinity to the antagonist [(3)H] DPCPX was slightly increased in total membrane extracts of hippocampus from preconditioned mice. Next, we evaluated the impact of NMDA preconditioning on A1R functioning by measuring the A1R-mediated regulation of glutamate uptake into hippocampal slices and on behavioral responses in the open field and hot plate tests. NMDA preconditioning increased glutamate uptake into hippocampal slices without altering the expression of glutamate transporter GLT-1. Interestingly, NMDA preconditioning also induced antinociception in the hot plate test and both effects were reversed by post-activation of A1R with the agonist CCPA (0.2mg/kg, i.p.). NMDA preconditioning or A1R modulation did not alter locomotor activity in the open field. Overall, the results described herein provide new evidence that post-activation of A1R modulates NMDA preconditioning-mediated responses, pointing to the importance of the cross-talk between glutamatergic and adenosinergic systems to neuroprotection.

  11. Quantitative study in vivo of methionine cycle in humans using (methyl-/sup 2/H/sub 3/)- and (1-/sup 13/C)methionine

    SciTech Connect

    Storch, K.J.; Wagner, D.A.; Burke, J.F.; Young, V.R.

    1988-09-01

    Kinetic aspects of body methionine (MET) metabolism were examined in healthy young men during the fed and postabsorptive (PA) states. Rates of MET incorporation (S) into and release (B) from body proteins; transmethylation (TM); and remethylation (RM) and transsulfuration (TS) of homocysteine (HCY) were estimated with the aid of a 5-h constant intravenous infusion of (methyl-2H3)- and (1-13C)methionine. The isotopic data (plasma methionine labeling and 13C enrichment of expired air) were submitted to a stochastic model of amino acid metabolism. During the fed state, the subjects (n = 4) received, at 20-min intervals, small isonitrogenous isocaloric meals containing a complete L-amino acid mixture supplying MET at a rate equivalent to 198 mumol.kg body wt-1.day-1. The PA subjects (n = 4) received the isotope after a 10-h overnight fast. For the PA group, the components of MET metabolism were as follows: S, 20 +/- 0.5; B, 24 +/- 0.5; TM, 5.8 +/- 0.6; RM, 1.8 +/- 0.4; and TS, 4.0 +/- 0.4 (+/-SE) mumol.kg-1.h-1. During the fed state the values were S, 26 +/- 2.5; B, 18 +/- 2; TM, 14 +/- 1.3; RM, 5.7 +/- 0.9; and TS 8.3 +/- 0.6 mumol.kg-1.h-1. The meal-induced changes in B, TM, RM, and TS were significant (P less than 0.05). Comparison of the partitioning of MET between S and TM (these two pathways of MET disposal constitute the ''methionine locus'') in the PA and in the fed states indicates that the MET locus is of regulatory importance in MET homeostasis. A twofold increase in the partitioning of MET to TM was observed in the fed state. The increase in HCY recycling, relative to TS (these two pathways of HCY disposal constitute the ''HCY locus''), in the fed state did not reach statistical significance when compared with the PA state. Total daily TM are estimated to be 238 +/- 22 mumol/kg. This is similar to the estimate generated by the methyl balance model of Mudd and Poole which approximated 241 mumol/kg.

  12. Alternative Oxidase Activity in Tobacco Leaf Mitochondria (Dependence on Tricarboxylic Acid Cycle-Mediated Redox Regulation and Pyruvate Activation).

    PubMed

    Vanlerberghe, G. C.; Day, D. A.; Wiskich, J. T.; Vanlerberghe, A. E.; McIntosh, L.

    1995-10-01

    Transgenic Nicotiana tabacum (cv Petit Havana SR1) containing high levels of mitochondrial alternative oxidase (AOX) protein due to the introduction of a sense transgene(s) of Aox1, the nuclear gene encoding AOX, were used to investigate mechanisms regulating AOX activity. After purification of leaf mitochondria, a large proportion of the AOX protein was present as the oxidized (covalently associated and less active) dimer. High AOX activity in these mitochondria was dependent on both reduction of the protein by DTT (to the noncovalently associated and more active dimer) and its subsequent activation by certain [alpha]-keto acids, particularly pyruvate. Reduction of AOX to its more active form could also be mediated by intramitochondrial reducing power generated by the oxidation of certain tricarboxylic acid cycle substrates, most notably isocitrate and malate. Our evidence suggests that NADPH may be specifically required for AOX reduction. All of the above regulatory mechanisms applied to AOX in wild-type mitochondria as well. Tran