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Sample records for acetyl transferase chat

  1. Structural and biochemical analyses reveal how ornithine acetyl transferase binds acidic and basic amino acid substrates.

    PubMed

    Iqbal, Aman; Clifton, Ian J; Chowdhury, Rasheduzzaman; Ivison, David; Domene, Carmen; Schofield, Christopher J

    2011-09-21

    Structural and biochemical analyses reveal how ornithine acetyl-transferases catalyse the reversible transfer of an acetyl-group from a basic (ornithine) to an acidic (glutamate) amino acid by employing a common mechanism involving an acetyl-enzyme intermediate but using different side chain binding modes. PMID:21796301

  2. SIAH-mediated ubiquitination and degradation of acetyl-transferases regulate the p53 response and protein acetylation.

    PubMed

    Grishina, Inna; Debus, Katherina; García-Limones, Carmen; Schneider, Constanze; Shresta, Amit; García, Carlos; Calzado, Marco A; Schmitz, M Lienhard

    2012-12-01

    Posttranslational modification of proteins by lysine acetylation regulates many biological processes ranging from signal transduction to chromatin compaction. Here we identify the acetyl-transferases CBP/p300, Tip60 and PCAF as new substrates for the ubiquitin E3 ligases SIAH1 and SIAH2. While CBP/p300 can undergo ubiquitin/proteasome-dependent degradation by SIAH1 and SIAH2, the two other acetyl-transferases are exclusively degraded by SIAH2. Accordingly, SIAH-deficient cells show enhanced protein acetylation, thus revealing SIAH proteins as indirect regulators of the cellular acetylation status. Functional experiments show that Tip60/PCAF-mediated acetylation of the tumor suppressor p53 is antagonized by the p53 target gene SIAH2 which mediates ubiquitin/proteasome-mediated degradation of both acetyl-transferases and consequently diminishes p53 acetylation and transcriptional activity. The p53 kinase HIPK2 mediates hierarchical phosphorylation of SIAH2 at 5 sites, which further boosts its activity as a ubiquitin E3 ligase for several substrates and therefore dampens the late p53 response. PMID:23044042

  3. Post-transcriptional regulation of chloramphenicol acetyl transferase.

    PubMed Central

    Byeon, W H; Weisblum, B

    1984-01-01

    The +1 site for initiation of inducible chloramphenicol acetyl transferase (CAT) mRNA encoded by plasmid pC194 was determined experimentally by using [alpha-32P]ATP-labeled runoff transcripts partially digested with T1 RNase. By partial digestion of the in vitro transcripts with S1, T1, and cobra venom nucleases as probes of mRNA conformation, single- and double-stranded regions, respectively, were also identified. Thus, a prominent inverted complementary repeat sequence was demonstrated spanning the +14 to +50 positions, which contain the complementary sequences CCUCC and GGAGG (the Shine and Dalgarno sequence for synthesis of CAT) symmetrically apposed and paired as part of a perfect 12-base-pair inverted complementary repeat sequence (-19.5 kcal [ca. -81.7 kJ] per mol). The CAT mRNA was stable to digestion by T1 RNase at the four guanosine residues in the Shine and Dalgarno sequence GGAGG , even at 60 degrees C, suggesting that nascent CAT mRNA allows ribosomes to initiate protein synthesis inefficiently and that induction involves post-transcriptional unmasking of the Shine and Dalgarno sequence. Consistent with this model of regulation, we found that cells carrying pC194 , induced with chloramphenicol, contain about the same concentration of pulse-labeled CAT-specific RNA as do uninduced cells. Induction of CAT synthesis by the non- acetylatable chloramphenicol analog fluorothiamphenicol was tested by using minicells of Bacillus subtilis carrying pC194 as well as minicells containing the cloned pC194 derivatives in which parts of the CAT structural gene were deleted in vitro with BAL 31 exonuclease. Optimal induction of both full-length (active) and deleted (inactive) CAT required similar concentrations of fluorothiamphenicol, whereas induction by chloramphenicol required a higher concentration for the wild-type full-length (active) CAT than for the (inactive) deleted CAT. Because synthesis of deleted CAT was inducible, we infer that CAT plays no direct role

  4. The HTLV-1-encoded protein HBZ directly inhibits the acetyl transferase activity of p300/CBP

    PubMed Central

    Wurm, Torsten; Wright, Diana G.; Polakowski, Nicholas; Mesnard, Jean-Michel; Lemasson, Isabelle

    2012-01-01

    The homologous cellular coactivators p300 and CBP contain intrinsic lysine acetyl transferase (termed HAT) activity. This activity is responsible for acetylation of several sites on the histones as well as modification of transcription factors. In a previous study, we found that HBZ, encoded by the Human T-cell Leukemia Virus type 1 (HTLV-1), binds to multiple domains of p300/CBP, including the HAT domain. In this study, we found that HBZ inhibits the HAT activity of p300/CBP through the bZIP domain of the viral protein. This effect correlated with a reduction of H3K18 acetylation, a specific target of p300/CBP, in cells expressing HBZ. Interestingly, lower levels of H3K18 acetylation were detected in HTLV-1 infected cells compared to non-infected cells. The inhibitory effect of HBZ was not limited to histones, as HBZ also inhibited acetylation of the NF-κB subunit, p65, and the tumor suppressor, p53. Recent studies reported that mutations in the HAT domain of p300/CBP that cause a defect in acetylation are found in certain types of leukemia. These observations suggest that inhibition of the HAT activity by HBZ is important for the development of adult T-cell leukemia associated with HTLV-1 infection. PMID:22434882

  5. Meta-analysis of the relationship between slow acetylation of N-acetyl transferase 2 and the risk of bladder cancer.

    PubMed

    An, Y; Li, H; Wang, K J; Liu, X H; Qiu, M X; Liao, Y; Huang, J L; Wang, X S

    2015-01-01

    The incidence of bladder cancer is closely associated with exposure to aromatic amines, that can cause cancer only after metabolic activation regulated by N-acetyl transferase 1 and 2 (NAT1 and NAT2). Many studies have indicated that slow acetylation of NAT2 increases the risk of bladder cancer. The major risk factor is tobacco smoke; however, some studies have failed to prove this. This study attempted to explore the correlation between NAT2 slow acetylation and bladder cancer risk through a meta-analysis of published case-control studies. Studies detecting NAT2 gene status in bladder cancer patients and healthy controls were retrieved from PubMed, Cochrane, EMchrane, CBM, and CNKI. We retrieved the data of cited articles and publications to identify and compare NAT2 gene in bladder cancer patients and healthy controls. The variables within and between the studies were also considered. The META module in the Stata v.6.0 software was used for data analysis. Twenty independent studies were enrolled in our meta-analysis according to the inclusion and exclusion criteria. Individual differences in the bladder cancer susceptibility were, in part, attributed to the effect of carcinogens. The merged odds ratio of the effect of slow acetylation on bladder cancer was 1.31 (95% confidence interval = 1.11-1.55). In conclusion, NAT2 slow acetylation state was associated with bladder cancer risk, and was shown to modestly increase the risk of bladder cancer. PMID:26681036

  6. Mimicking Insect Communication: Release and Detection of Pheromone, Biosynthesized by an Alcohol Acetyl Transferase Immobilized in a Microreactor

    PubMed Central

    Muñoz, Lourdes; Dimov, Nikolay; Carot-Sans, Gerard; Bula, Wojciech P.; Guerrero, Angel; Gardeniers, Han J. G. E.

    2012-01-01

    Infochemical production, release and detection of (Z,E)-9,11-tetradecadienyl acetate, the major component of the pheromone of the moth Spodoptera littoralis, is achieved in a novel microfluidic system designed to mimic the final step of the pheromone biosynthesis by immobilized recombinant alcohol acetyl transferase. The microfluidic system is part of an “artificial gland”, i.e., a chemoemitter that comprises a microreactor connected to a microevaporator and is able to produce and release a pre-defined amount of the major component of the pheromone from the corresponding (Z,E)-9,11-tetradecadienol. Performance of the entire chemoemitter has been assessed in electrophysiological and behavioral experiments. Electroantennographic depolarizations of the pheromone produced by the chemoemitter were ca. 40% relative to that evoked by the synthetic pheromone. In a wind tunnel, the pheromone released from the evaporator elicited on males a similar attraction behavior as 3 virgin females in most of the parameters considered. PMID:23155372

  7. Anatomy of a simple acyl intermediate in enzyme catalysis: combined biophysical and modeling studies on ornithine acetyl transferase.

    PubMed

    Iqbal, Aman; Clifton, Ian J; Bagonis, Maria; Kershaw, Nadia J; Domene, Carmen; Claridge, Timothy D W; Wharton, Christopher W; Schofield, Christopher J

    2009-01-21

    Acyl-enzyme complexes are intermediates in reactions catalyzed by many hydrolases and related enzymes which employ nucleophilic catalysis. However, most of the reported structural data on acyl-enzyme complexes has been acquired under noncatalytic conditions. Recent IR analyses have indicated that some acyl-enzyme complexes may be more flexible than most crystallographic analyses have implied. OAT2 is a member of the N-terminal nucleophile (Ntn) hydrolase enzyme superfamily and catalyzes the reversible transfer of an acetyl group between the alpha-amino groups of ornithine and glutamate in a mechanism proposed to involve an acyl-enzyme complex. We have carried out biophysical analyses on ornithine acetyl transferase (OAT2), both in solution and in the crystalline state. Mass spectrometric studies identified Thr-181 as the residue acetylated during OAT2 catalysis; (13)C NMR analyses implied the presence of an acyl-enzyme complex in solution. Crystallization of OAT2 in the presence of N-alpha-acetyl-L-glutamate led to a structure in which Thr-181 was acetylated; the carbonyl oxygen of the acyl-enzyme complex was located in an oxyanion hole and positioned to hydrogen bond with the backbone amide NH of Gly-112 and the alcohol of Thr-111. While the crystallographic analyses revealed only one structure, IR spectroscopy demonstrated the presence of two distinct acyl-enzyme complex structures with carbonyl stretching frequencies at 1691 and 1701 cm(-1). Modeling studies implied two possible acyl-enzyme complex structures, one of which correlates with that observed in the crystal structure and with the 1691 cm(-1) IR absorption. The second acyl-enzyme complex structure, which has only a single oxyanion hole hydrogen bond, is proposed to give rise to the 1701 cm(-1) IR absorption. The two acyl-enzyme complex structures can interconvert by movement of the Thr-111 side-chain alcohol hydrogen away from the oxyanion hole to hydrogen bond with the backbone carbonyl of the acylated

  8. The two paralogue phoN (phosphinothricin acetyl transferase) genes of Pseudomonas putida encode functionally different proteins.

    PubMed

    Páez-Espino, A David; Chavarría, Max; de Lorenzo, Víctor

    2015-09-01

    Phosphinothricin (PPT) is a non-specific inhibitor of glutamine synthetase that has been employed as herbicide for selection of transgenic plants expressing cognate resistance genes. While the soil bacterium Pseudomonas putida KT2440 has been generally considered PPT-sensitive, inspection of its genome sequence reveals the presence of two highly similar open reading frames (PP_1924 and PP_4846) encoding acetylases with a potential to cause tolerance to the herbicide. To explore this possibility, each of these genes (named phoN1 and phoN2) was separately cloned and their activities examined in vivo and in vitro. Genetic and biochemical evidence indicated that phoN1 encodes a bona fide PPT-acetyl transferase, the expression of which suffices to make P. putida tolerant to high concentrations of the herbicide. In contrast, PhoN2 does not act on PPT but displays instead activity against methionine sulfoximine (MetSox), another glutamine synthetase inhibitor. When the geometry of the substrate-binding site of PhoN1 was grafted with the equivalent residues of the predicted PhoN2 structure, the resulting protein increased significantly MetSox resistance of the expression host concomitantly with the loss of activity on PPT. These observations uncover intricate biochemical and genetic interactions among soil microorganisms and how they can be perturbed by exposure to generic herbicides in soil. PMID:25684119

  9. Thiopurine metabolites variations during co-treatment with aminosalicylates for inflammatory bowel disease: Effect of N-acetyl transferase polymorphisms

    PubMed Central

    Stocco, Gabriele; Cuzzoni, Eva; De Iudicibus, Sara; Favretto, Diego; Malusà, Noelia; Martelossi, Stefano; Pozzi, Elena; Lionetti, Paolo; Ventura, Alessandro; Decorti, Giuliana

    2015-01-01

    AIM: To evaluate variation of the concentration of thiopurine metabolites after 5-aminosalicylate (5-ASA) interruption and the role of genetic polymorphisms of N-acetyl transferase (NAT) 1 and 2. METHODS: Concentrations of thioguanine nucleotides (TGN) and methymercaptopurine nucleotides (MMPN), metabolites of thiopurines, were measured by high performance liquid chromatography in 12 young patients (3 females and 9 males, median age 16 years) with inflammatory bowel disease (6 Crohn’s disease and 6 ulcerative colitis) treated with thiopurines (7 mercaptopurine and 5 azathioprine) and 5-ASA. Blood samples were collected one month before and one month after the interruption of 5-ASA. DNA was extracted and genotyping of NAT1, NAT2, inosine triphosphate pyrophosphatase (ITPA) and thiopurine methyl transferase (TPMT) genes was performed using PCR assays. RESULTS: Median TGN concentration before 5-ASA interruption was 270 pmol/8 x 108 erythrocytes (range: 145-750); after the interruption of the aminosalicylate, a 35% reduction in TGN mean concentrations (absolute mean reduction 109 pmol/8 × 108 erythrocytes) was observed (median 221 pmol/8 × 108 erythrocytes, range: 96-427, P value linear mixed effects model 0.0011). Demographic and clinical covariates were not related to thiopurine metabolites concentrations. All patients were wild-type for the most relevant ITPA and TPMT variants. For NAT1 genotyping, 7 subjects presented an allele combination corresponding to fast enzymatic activity and 5 to slow activity. NAT1 genotypes corresponding to fast enzymatic activity were associated with reduced TGN concentration (P value linear mixed effects model 0.033), putatively because of increased 5-ASA inactivation and consequent reduced inhibition of thiopurine metabolism. The effect of NAT1 status on TGN seems to be persistent even after one month since the interruption of the aminosalicylate. No effect of NAT1 genotypes was shown on MMPN concentrations. NAT2 genotyping

  10. Arylamine N-acetyl Transferase (NAT) in the blue secretion of Telescopium telescopium: xenobiotic metabolizing enzyme as a biomarker for detection of environmental pollution.

    PubMed

    Gorain, Bapi; Chakraborty, Sumon; Pal, Murari Mohan; Sarkar, Ratul; Samanta, Samir Kumar; Karmakar, Sanmoy; Sen, Tuhinadri

    2014-01-01

    Telescopium telescopium, a marine mollusc collected from Sundarban mangrove, belongs to the largest mollusca phylum in the world and exudes a blue secretion when stimulated mechanically. The blue secretion was found to metabolize (preferentially) para-amino benzoic acid, a substrate for N-acetyl transferase (NAT), thereby indicating acetyl transferase like activity of the secretion. Attempts were also made to characterise bioactive fraction of the blue secretion and to further use this as a biomarker for monitoring of marine pollution. NAT like enzyme from marine mollusc is a potential candidate for detoxification of different harmful chemicals. A partially purified extract of blue secretion was obtained by fractional precipitation with (NH4)2SO4. From different fractions obtained by precipitation, the 0-30% fraction (30S) displayed NAT like activity (using para amino benzoic acid as a substrate with para nitrophenyl phosphate or acetyl coenzyme A as acetyl group donors). Maximum NAT like enzyme activity was attained at 25°C and at a pH of 6. The enzyme activity was found to be inhibited by 5 mM phenyl methyl sulfonyl fluoride. The divalent metal ions reduced NAT like activity of 30S. Moreover, Cu(2+) and Zn(2+) (at concentration of 1 mM) completely inhibited NAT activity. The thermal stability and bench-top stability studies were performed and it was found that the enzyme was stable at room temperature for more than 24 hours. Results from the present study further indicate that heavy metal content in blue secretion gradually decreased from pre-monsoon to post-monsoon season, which also corresponded to the change in NAT like activity. Therefore, this article stresses the importance of biomarker research for monitoring pollution. PMID:26034680

  11. Specific Synthesis of Neurostatin and Gangliosides O-Acetylated in the Outer Sialic Acids Using a Sialate Transferase

    PubMed Central

    Romero-Ramírez, Lorenzo; García-Álvarez, Isabel; Campos-Olivas, Ramón; Gilbert, Michel; Goneau, Marie-France; Fernández-Mayoralas, Alfonso; Nieto-Sampedro, Manuel

    2012-01-01

    Gangliosides are sialic acid containing glycosphingolipids, commonly found on the outer leaflet of the plasma membrane. O-acetylation of sialic acid hydroxyl groups is one of the most common modifications in gangliosides. Studies on the biological activity of O-acetylated gangliosides have been limited by their scarcity in nature. This comparatively small change in ganglioside structure causes major changes in their physiological properties. When the ganglioside GD1b was O-acetylated in the outer sialic acid, it became the potent inhibitor of astroblast and astrocytoma proliferation called Neurostatin. Although various chemical and enzymatic methods to O-acetylate commercial gangliosides have been described, O-acetylation was nonspecific and produced many side-products that reduced the yield. An enzyme with O-acetyltransferase activity (SOAT) has been previously cloned from the bacteria Campylobacter jejuni. This enzyme catalyzed the acetylation of oligosaccharide-bound sialic acid, with high specificity for terminal alpha-2,8-linked residues. Using this enzyme and commercial gangliosides as starting material, we have specifically O-acetylated the gangliosides’ outer sialic acids, to produce the corresponding gangliosides specifically O-acetylated in the sialic acid bound in alpha-2,3 and alpha-2,8 residues. We demonstrate here that O-acetylation occurred specifically in the C-9 position of the sialic acid. In summary, we present a new method of specific O-acetylation of ganglioside sialic acids that permits the large scale preparation of these modified glycosphingolipids, facilitating both, the study of their mechanism of antitumoral action and their use as therapeutic drugs for treating glioblastoma multiform (GBM) patients. PMID:23226505

  12. Crystal Structure of TDP-Fucosamine Acetyl Transferase (WECD) from Escherichia Coli, an Enzyme Required for Enterobacterial Common Antigen Synthesis

    SciTech Connect

    Hung,M.; Rangarajan, E.; Munger, C.; Nadeau, G.; Sulea, T.; Matte, A.

    2006-01-01

    Enterobacterial common antigen (ECA) is a polysaccharide found on the outer membrane of virtually all gram-negative enteric bacteria and consists of three sugars, N-acetyl-D-glucosamine, N-acetyl-D-mannosaminuronic acid, and 4-acetamido-4,6-dideoxy-D-galactose, organized into trisaccharide repeating units having the sequence {yields}(3)-{alpha}-D-Fuc4NAc-(1{yields}4)-{beta}-D-ManNAcA-(1{yields}4)-{alpha}-D-GlcNAc-(1{yields}). While the precise function of ECA is unknown, it has been linked to the resistance of Shiga-toxin-producing Escherichia coli (STEC) O157:H7 to organic acids and the resistance of Salmonella enterica to bile salts. The final step in the synthesis of 4-acetamido-4,6-dideoxy-D-galactose, the acetyl-coenzyme A (CoA)-dependent acetylation of the 4-amino group, is carried out by TDP-fucosamine acetyltransferase (WecD). We have determined the crystal structure of WecD in apo form at a 1.95-Angstroms resolution and bound to acetyl-CoA at a 1.66-Angstroms resolution. WecD is a dimeric enzyme, with each monomer adopting the GNAT N-acetyltransferase fold, common to a number of enzymes involved in acetylation of histones, aminoglycoside antibiotics, serotonin, and sugars. The crystal structure of WecD, however, represents the first structure of a GNAT family member that acts on nucleotide sugars. Based on this cocrystal structure, we have used flexible docking to generate a WecD-bound model of the acetyl-CoA-TDP-fucosamine tetrahedral intermediate, representing the structure during acetyl transfer. Our structural data show that WecD does not possess a residue that directly functions as a catalytic base, although Tyr208 is well positioned to function as a general acid by protonating the thiolate anion of coenzyme A.

  13. Isolation of a mutant Arabidopsis plant that lacks N-acetyl glucosaminyl transferase I and is unable to synthesize Golgi-modified complex N-linked glycans.

    PubMed Central

    von Schaewen, A; Sturm, A; O'Neill, J; Chrispeels, M J

    1993-01-01

    The complex asparagine-linked glycans of plant glycoproteins, characterized by the presence of beta 1-->2 xylose and alpha 1-->3 fucose residues, are derived from typical mannose9(N-acetylglucosamine)2 (Man9GlcNAc2) N-linked glycans through the activity of a series of glycosidases and glycosyl transferases in the Golgi apparatus. By screening leaf extracts with an antiserum against complex glycans, we isolated a mutant of Arabidopsis thaliana that is blocked in the conversion of high-manne to complex glycans. In callus tissues derived from the mutant plants, all glycans bind to concanavalin A. These glycans can be released by treatment with endoglycosidase H, and the majority has the same size as Man5GlcNAc1 glycans. In the presence of deoxymannojirimycin, an inhibitor of mannosidase I, the mutant cells synthesize Man9GlcNAc2 and Man8GlcNAc2 glycans, suggesting that the biochemical lesion in the mutant is not in the biosynthesis of high-mannose glycans in the endoplasmic reticulum but in their modification in the Golgi. Direct enzyme assays of cell extracts show that the mutant cells lack N-acetyl glucosaminyl transferase I, the first enzyme in the pathway of complex glycan biosynthesis. The mutant plants are able to complete their development normally under several environmental conditions, suggesting that complex glycans are not essential for normal developmental processes. By crossing the complex-glycan-deficient strain of A. thaliana with a transgenic strain that expresses the glycoprotein phytohemagglutinin, we obtained a unique strain that synthesizes phytohemagglutinin with two high-mannose glycans, instead of one high-mannose and one complex glycan. PMID:8278542

  14. Purification and characterization of a cytoplasmic enzyme component of the Na+-activated malonate decarboxylase system of Malonomonas rubra: acetyl-S-acyl carrier protein: malonate acyl carrier protein-SH transferase.

    PubMed

    Hilbi, H; Dimroth, P

    1994-01-01

    Malonate decarboxylation by crude extracts of Malonomonas rubra was specifically activated by Na+ and less efficiently by Li+ ions. The extracts contained an enzyme catalyzing CoA transfer from malonyl-CoA to acetate, yielding acetyl-CoA and malonate. After about a 26-fold purification of the malonyl-CoA:acetate CoA transferase, an almost pure enzyme was obtained, indicating that about 4% of the cellular protein consisted of the CoA transferase. This abundance of the transferase is in accord with its proposed role as an enzyme component of the malonate decarboxylase system, the key enzyme of energy metabolism in this organism. The apparent molecular weight of the polypeptide was 67,000 as revealed from SDS-polyacrylamide gel electrophoresis. A similar molecular weight was estimated for the native transferase by gel chromatography, indicating that the enzyme exists as a monomer. Kinetic analyses of the CoA transferase yielded the following: pH-optimum at pH 5.5, an apparent Km for malonyl-CoA of 1.9mM, for acetate of 54mM, for acetyl-CoA of 6.9mM, and for malonate of 0.5mM. Malonate or citrate inhibited the enzyme with an apparent Ki of 0.4mM and 3.0mM, respectively. The isolated CoA transferase increased the activity of malonate decarboxylase of a crude enzyme system, in which part of the endogenous CoA transferase was inactivated by borohydride, about three-fold. These results indicate that the CoA transferase functions physiologically as a component of the malonate decarboxylase system, in which it catalyzes the transfer of acyl carrier protein from acetyl acyl carrier protein and malonate to yield malonyl acyl carrier protein and acetate. Malonate is thus activated on the enzyme by exchange for the catalytically important enzymebound acetyl thioester residues noted previously. This type of substrate activation resembles the catalytic mechanism of citrate lyase and citramalate lyase. PMID:18251085

  15. N-acetyl-cysteine prevents age-related hearing loss and the progressive loss of inner hair cells in γ-glutamyl transferase 1 deficient mice.

    PubMed

    Ding, Dalian; Jiang, Haiyan; Chen, Guang-Di; Longo-Guess, Chantal; Muthaiah, Vijaya Prakash Krishnan; Tian, Cong; Sheppard, Adam; Salvi, Richard; Johnson, Kenneth R

    2016-04-01

    Genetic factors combined with oxidative stress are major determinants of age-related hearing loss (ARHL), one of the most prevalent disorders of the elderly. Dwarf grey mice, Ggt1dwg/dwg, are homozygous for a loss of function mutation of the g-glutamyl transferase 1 gene, which encodes an important antioxidant enzyme critical for the resynthesis of glutathione (GSH). Since GSH reduces oxidative damage, we hypothesized that Ggt1dwg/dwg mice would be susceptible to ARHL. Surprisingly, otoacoustic emissions and cochlear microphonic potentials, which reflect cochlear outer hair cell (OHC) function, were largely unaffected in mutant mice, whereas auditory brainstem responses and the compound action potential were grossly abnormal. These functional deficits were associated with an unusual and selective loss of inner hair cells (IHC), but retention of OHC and auditory nerve fibers. Remarkably, hearing deficits and IHC loss were completely prevented by N-acetyl-L-cysteine, which induces de novo synthesis of GSH; however, hearing deficits and IHC loss reappeared when treatment was discontinued. Ggt1dwg/dwg mice represent an important new model for investigating ARHL, therapeutic interventions, and understanding the perceptual and electrophysiological consequences of sensory deprivation caused by the loss of sensory input exclusively from IHC. PMID:26977590

  16. N-acetyl-cysteine prevents age-related hearing loss and the progressive loss of inner hair cells in γ-glutamyl transferase 1 deficient mice

    PubMed Central

    Ding, Dalian; Jiang, Haiyan; Chen, Guang-Di; Longo-Guess, Chantal; Muthaiah, Vijaya Prakash Krishnan; Tian, Cong; Sheppard, Adam; Salvi, Richard; Johnson, Kenneth R.

    2016-01-01

    Genetic factors combined with oxidative stress are major determinants of age-related hearing loss (ARHL), one of the most prevalent disorders of the elderly. Dwarf grey mice, Ggt1dwg/dwg, are homozygous for a loss of function mutation of the γ-glutamyl transferase 1 gene, which encodes an important antioxidant enzyme critical for the resynthesis of glutathione (GSH). Since GSH reduces oxidative damage, we hypothesized that Ggt1dwg/dwg mice would be susceptible to ARHL. Surprisingly, otoacoustic emissions and cochlear microphonic potentials, which reflect cochlear outer hair cell (OHC) function, were largely unaffected in mutant mice, whereas auditory brainstem responses and the compound action potential were grossly abnormal. These functional deficits were associated with an unusual and selective loss of inner hair cells (IHC), but retention of OHC and auditory nerve fibers. Remarkably, hearing deficits and IHC loss were completely prevented by N-acetyl-L-cysteine, which induces de novo synthesis of GSH; however, hearing deficits and IHC loss reappeared when treatment was discontinued. Ggt1dwg/dwgmice represent an important new model for investigating ARHL, therapeutic interventions, and understanding the perceptual and electrophysiological consequences of sensory deprivation caused by the loss of sensory input exclusively from IHC. PMID:26977590

  17. Popular Chat Day Q & A

    MedlinePlus

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  18. De Novo Nonsense Mutations in KAT6A, a Lysine Acetyl-Transferase Gene, Cause a Syndrome Including Microcephaly and Global Developmental Delay

    PubMed Central

    Arboleda, Valerie A.; Lee, Hane; Dorrani, Naghmeh; Zadeh, Neda; Willis, Mary; Macmurdo, Colleen Forsyth; Manning, Melanie A.; Kwan, Andrea; Hudgins, Louanne; Barthelemy, Florian; Miceli, M. Carrie; Quintero-Rivera, Fabiola; Kantarci, Sibel; Strom, Samuel P.; Deignan, Joshua L.; Grody, Wayne W.; Vilain, Eric; Nelson, Stanley F.

    2015-01-01

    Chromatin remodeling through histone acetyltransferase (HAT) and histone deactylase (HDAC) enzymes affects fundamental cellular processes including the cell-cycle, cell differentiation, metabolism, and apoptosis. Nonsense mutations in genes that are involved in histone acetylation and deacetylation result in multiple congenital anomalies with most individuals displaying significant developmental delay, microcephaly and dysmorphism. Here, we report a syndrome caused by de novo heterozygous nonsense mutations in KAT6A (a.k.a., MOZ, MYST3) identified by clinical exome sequencing (CES) in four independent families. The same de novo nonsense mutation (c.3385C>T [p.Arg1129∗]) was observed in three individuals, and the fourth individual had a nearby de novo nonsense mutation (c.3070C>T [p.Arg1024∗]). Neither of these variants was present in 1,815 in-house exomes or in public databases. Common features among all four probands include primary microcephaly, global developmental delay including profound speech delay, and craniofacial dysmorphism, as well as more varied features such as feeding difficulties, cardiac defects, and ocular anomalies. We further demonstrate that KAT6A mutations result in dysregulation of H3K9 and H3K18 acetylation and altered P53 signaling. Through histone and non-histone acetylation, KAT6A affects multiple cellular processes and illustrates the complex role of acetylation in regulating development and disease. PMID:25728775

  19. De novo nonsense mutations in KAT6A, a lysine acetyl-transferase gene, cause a syndrome including microcephaly and global developmental delay.

    PubMed

    Arboleda, Valerie A; Lee, Hane; Dorrani, Naghmeh; Zadeh, Neda; Willis, Mary; Macmurdo, Colleen Forsyth; Manning, Melanie A; Kwan, Andrea; Hudgins, Louanne; Barthelemy, Florian; Miceli, M Carrie; Quintero-Rivera, Fabiola; Kantarci, Sibel; Strom, Samuel P; Deignan, Joshua L; Grody, Wayne W; Vilain, Eric; Nelson, Stanley F

    2015-03-01

    Chromatin remodeling through histone acetyltransferase (HAT) and histone deactylase (HDAC) enzymes affects fundamental cellular processes including the cell-cycle, cell differentiation, metabolism, and apoptosis. Nonsense mutations in genes that are involved in histone acetylation and deacetylation result in multiple congenital anomalies with most individuals displaying significant developmental delay, microcephaly and dysmorphism. Here, we report a syndrome caused by de novo heterozygous nonsense mutations in KAT6A (a.k.a., MOZ, MYST3) identified by clinical exome sequencing (CES) in four independent families. The same de novo nonsense mutation (c.3385C>T [p.Arg1129∗]) was observed in three individuals, and the fourth individual had a nearby de novo nonsense mutation (c.3070C>T [p.Arg1024∗]). Neither of these variants was present in 1,815 in-house exomes or in public databases. Common features among all four probands include primary microcephaly, global developmental delay including profound speech delay, and craniofacial dysmorphism, as well as more varied features such as feeding difficulties, cardiac defects, and ocular anomalies. We further demonstrate that KAT6A mutations result in dysregulation of H3K9 and H3K18 acetylation and altered P53 signaling. Through histone and non-histone acetylation, KAT6A affects multiple cellular processes and illustrates the complex role of acetylation in regulating development and disease. PMID:25728775

  20. Histone Acetyl Transferase 1 Is Essential for Mammalian Development, Genome Stability, and the Processing of Newly Synthesized Histones H3 and H4

    PubMed Central

    Nagarajan, Prabakaran; Ge, Zhongqi; Sirbu, Bianca; Doughty, Cheryl; Agudelo Garcia, Paula A.; Schlederer, Michaela; Annunziato, Anthony T.; Cortez, David; Kenner, Lukas; Parthun, Mark R.

    2013-01-01

    Histone acetyltransferase 1 is an evolutionarily conserved type B histone acetyltransferase that is thought to be responsible for the diacetylation of newly synthesized histone H4 on lysines 5 and 12 during chromatin assembly. To understand the function of this enzyme in a complex organism, we have constructed a conditional mouse knockout model of Hat1. Murine Hat1 is essential for viability, as homozygous deletion of Hat1 results in neonatal lethality. The lungs of embryos and pups genetically deficient in Hat1 were much less mature upon histological evaluation. The neonatal lethality is due to severe defects in lung development that result in less aeration and respiratory distress. Many of the Hat1−/− neonates also display significant craniofacial defects with abnormalities in the bones of the skull and jaw. Hat1−/− mouse embryonic fibroblasts (MEFs) are defective in cell proliferation and are sensitive to DNA damaging agents. In addition, the Hat1−/− MEFs display a marked increase in genome instability. Analysis of histone dynamics at sites of replication-coupled chromatin assembly demonstrates that Hat1 is not only responsible for the acetylation of newly synthesized histone H4 but is also required to maintain the acetylation of histone H3 on lysines 9, 18, and 27 during replication-coupled chromatin assembly. PMID:23754951

  1. Chat Reference. SPEC Kit.

    ERIC Educational Resources Information Center

    Ronan, Jana, Comp.; Turner, Carol, Comp.

    2002-01-01

    This SPEC (Systems and Procedures Exchange Center) Kit presents the results of a survey of Association of Research Libraries (ARL) member libraries designed to gather data on chat reference service. A total of 66 of 124 ARL member libraries responded to the survey. A copy of the questionnaire with tabulated results is presented. Representative…

  2. Internet Relay Chat.

    ERIC Educational Resources Information Center

    Simpson, Carol

    2000-01-01

    Describes Internet Relay Chats (IRCs), electronic conversations over the Internet that allow multiple users to write messages, and their applications to educational settings such as teacher collaboration and conversations between classes. Explains hardware and software requirements, IRC organization into nets and channels, and benefits and…

  3. Chatting in Paragraphs: Towards Academic Discourse in Foreign Language Chat

    ERIC Educational Resources Information Center

    Mendelson, Adam

    2012-01-01

    This paper presents a case study of an individual student's increasing approximation of academic discourse during a third-semester Spanish class that included chat-based instruction. During both chat-based activities and oral discussions in class, the student's language use became increasingly characterized by longer turns and the use of…

  4. Integrating CHAT and Action Research

    ERIC Educational Resources Information Center

    Wells, Gordon

    2011-01-01

    The question as to how action research (AR) is related to cultural-historical activity theory (CHAT) is not answerable in categorical terms. Both CHAT and AR have been variously interpreted and much depends on the individual biographies of those who pronounce on their relationship. The aim of this paper is to show how action research, conducted…

  5. Cri du Chat syndrome

    PubMed Central

    Cerruti Mainardi, Paola

    2006-01-01

    The Cri du Chat syndrome (CdCS) is a genetic disease resulting from a deletion of variable size occurring on the short arm of chromosome 5 (5p-). The incidence ranges from 1:15,000 to 1:50,000 live-born infants. The main clinical features are a high-pitched monochromatic cry, microcephaly, broad nasal bridge, epicanthal folds, micrognathia, abnormal dermatoglyphics, and severe psychomotor and mental retardation. Malformations, although not very frequent, may be present: cardiac, neurological and renal abnormalities, preauricular tags, syndactyly, hypospadias, and cryptorchidism. Molecular cytogenetic analysis has allowed a cytogenetic and phenotypic map of 5p to be defined, even if results from the studies reported up to now are not completely in agreement. Genotype-phenotype correlation studies showed a clinical and cytogenetic variability. The identification of phenotypic subsets associated with a specific size and type of deletion is of diagnostic and prognostic relevance. Specific growth and psychomotor development charts have been established. Two genes, Semaphorin F (SEMAF) and δ-catenin (CTNND2), which have been mapped to the "critical regions", are potentially involved in cerebral development and their deletion may be associated with mental retardation in CdCS patients. Deletion of the telomerase reverse transcriptase (hTERT) gene, localised to 5p15.33, could contribute to the phenotypic changes in CdCS. The critical regions were recently refined by using array comparative genomic hybridisation. The cat-like cry critical region was further narrowed using quantitative polymerase chain reaction (PCR) and three candidate genes were characterised in this region. The diagnosis is based on typical clinical manifestations. Karyotype analysis and, in doubtful cases, FISH analysis will confirm the diagnosis. There is no specific therapy for CdCS but early rehabilitative and educational interventions improve the prognosis and considerable progress has been made in

  6. Learning about Cri du Chat Syndrome

    MedlinePlus

    ... chat syndrome - also known as 5p- syndrome and cat cry syndrome - is a rare genetic condition that ... du chat syndrome usually include a high-pitched cat-like cry, mental retardation, delayed development, distinctive facial ...

  7. Internet Chat in Simulations: Taking BULLYING Online

    ERIC Educational Resources Information Center

    Hull, Emily Blackshear

    2008-01-01

    This article discusses the pedagogical implications of using Internet chat in simulations for second-language learners. The author reviews several published simulations and explains how to use Internet chat effectively in the classroom. The author also relays her experience with using Internet chat with the BULLYING simulation.

  8. TESTING AND ANALYSES OF CHAT AND ASPHALT-CONTAINING CHAT

    EPA Science Inventory

    Granular mine waste are generated from the extraction and beneficiation of lead/zinc minerals. The fine gravel waste, commonly known as chat, in the Tristate Mining District contains elevated levels of lead, zinc and cadmium which can result in potentially serious human health a...

  9. Chat Widgets for Science Libraries

    ERIC Educational Resources Information Center

    Meier, John J.

    2008-01-01

    This paper describes chat widgets, chunks of code that can be embedded on a web site to appear as an instant messaging system, and how they can be used on a science library web site to better serve library users. Interviews were conducted concerning experiences at science and humanities libraries and more similarities than differences were…

  10. Small CHAT plant. Final report

    SciTech Connect

    Nakhamkin, M.; Swenson, E.

    1997-11-01

    The Cascaded Humidified Advanced Turbine (CHAT) concept applied to small capacity simple cycle gas turbines fulfills the need for a small capacity, highly efficient, cost effective, flexible, and reliable plant with near term delivery. The objective of this report is to provide a status of the development of the small CHAT plant based including performance and cost estimates, potential suppliers, and operating advantages offered by the cycle itself. The small CHAT plant based upon the use of the Allison 501 KM7 engine on the low pressure power generation shaft produces 11.1 MW at ISO conditions with a net plant efficiency of 44.1%, LHV. This design requires only minor modification to the Allison KM engine. At maximum power, the plant can produce 12.8 MW at an efficiency of 43.1%. The estimated turn key capital cost of the plant at maximum power rating is approximately $750/kW. The next generation CHAT plant which requires additional modification to the Allison shaft is expected to produce 12.2 MW at 46.4% efficiency.

  11. Acetyl chloride

    Integrated Risk Information System (IRIS)

    Acetyl chloride ; CASRN 75 - 36 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  12. Virtual reference: chat with us!

    PubMed

    Lapidus, Mariana; Bond, Irena

    2009-01-01

    Virtual chat services represent an exciting way to provide patrons of medical libraries with instant reference help in an academic environment. The purpose of this article is to examine the implementation, marketing process, use, and development of a virtual reference service initiated at the Massachusetts College of Pharmacy and Health Sciences and its three-campus libraries. In addition, this paper will discuss practical recommendations for the future improvement of the service. PMID:19384714

  13. Going Prime Time with Live Chat Reference.

    ERIC Educational Resources Information Center

    Hoag, Tara J.; Cichanowicz, Edana McCaffrey

    2001-01-01

    Describes the development of the Suffolk Cooperative Library System's live, online chat reference service, a pilot project for public libraries in Suffolk County (New York). Topics include chat software selection; a virtual reference collection; marketing; funding; staffing; evaluation; expanded hours of service; email; and extracting data from…

  14. Investigating L2 Performance in Text Chat

    ERIC Educational Resources Information Center

    Sauro, Shannon; Smith, Bryan

    2010-01-01

    This study examines the linguistic complexity and lexical diversity of both overt and covert L2 output produced during synchronous written computer-mediated communication, also referred to as chat. Video enhanced chatscripts produced by university learners of German (N = 23) engaged in dyadic task-based chat interaction were coded and analyzed for…

  15. Focus on Form in Live Chats

    ERIC Educational Resources Information Center

    Chen, Wen-Chun; Eslami, Zohreh

    2013-01-01

    This study investigated the effectiveness of incidental focus on form in promoting second language development in text-based live chats. Sixteen college-level Taiwanese English language learners were partnered with American college students to complete two communicative tasks via synchronous chats on Instant Messenger. Language-related episodes…

  16. Chat reference service in medical libraries: part 1--An introduction.

    PubMed

    Dee, Cheryl R

    2003-01-01

    Chat reference services offer the opportunity to provide immediate access to quality information to meet the medical information needs of students, faculty, staff, physicians, nurses, and allied health care professionals. Part 1 of this two-part article on chat reference service in medical libraries is an introduction to the management of chat reference services and to features available for chat reference. The management of chat reference services raises issues of planning, staffing, selecting, and marketing. Planning issues focus on the identification of the users, the users' medical information needs, and the users' information-seeking behavior. Staffing issues relate to the selection of chat hours, the location of the chat service, and participation in collaborative agreements. Selecting chat software weighs the sophistication of the chat features against the related cost. Marketing uses techniques similar to traditional reference services and often begins slowly as chat expertise develops. Part 2 of the article discusses trends in chat reference services in medical libraries. PMID:12723810

  17. Extending Prior Posts in Dyadic Online Text Chat

    ERIC Educational Resources Information Center

    Tudini, Vincenza

    2015-01-01

    This study explores whether chat users are able to extend prior, apparently completed posts in the dyadic online text chat context. Dyadic text chat has a unique turn-taking system, and most chat softwares do not permit users to monitor one another's written messages-in-progress. This is likely to impact on their use of online extensions as an…

  18. Perfume formulation: words and chats.

    PubMed

    Ellena, Céline

    2008-06-01

    What does it mean to create fragrances with materials from chemistry and/or from nature? How are they used to display their characteristic differences, their own personality? Is it easier to create with synthetic raw materials or with essential oils? This review explains why a perfume formulation corresponds in fact to a conversation, an interplay between synthetic and natural perfumery materials. A synthetic raw material carries a single information, and usually is very linear. Its smell is uniform, clear, and faithful. Natural raw materials, on the contrary, provide a strong, complex and generous image. While a synthetic material can be seen as a single word, a natural one such as rose oil could be compared to chatting: cold, warm, sticky, heavy, transparent, pepper, green, metallic, smooth, watery, fruity... full of information. Yet, if a very small amount of the natural material is used, nothing happens, the fragrance will not change. However, if a large amount is used, the rose oil will swallow up everything else. The fragrance will smell of nothing else except rose! To formulate a perfume is not to create a culinary recipe, with only dosing the ingredients in well-balanced amounts. To formulate rather means to flexibly knit materials together with a lively stitch, meeting or repelling each other, building a pleasant form, which is neither fixed, nor solid, nor rigid. A fragrance has an overall structure, which ranges from a clear sound, made up of stable, unique, and linear items, to a background chat, comfortable and reassuring. But that does, of course, not mean that there is only one way of creating a fragrance! PMID:18618806

  19. The Cascaded Humidified Advanced Turbine (CHAT)

    SciTech Connect

    Nakhamkin, M.; Swensen, E.C.; Wilson, J.M.; Gaul, G.; Polsky, M.

    1996-07-01

    This paper introduces the Cascaded Humidified Advanced Turbine (CHAT) plant, a gas turbine based power generation plant utilizing intercooling, reheat, and humidification. It is based upon the integration of an existing heavy duty gas turbine with an additional shaft comprising industrial compressors and high pressure expander. CHAT capitalizes on the latest proven gas turbine technology, which, combined with a sophisticated thermal cycle configuration, results in substantial improvement in gas turbine efficiency, compared to a simple cycle, while still maintaining typical advantages and merits of a combustion turbine plant. Built with a commercial combustion turbine and available industrial compressors and expanders, the CHAT plant does not require extensive product development and testing. As a result, the CHAT power plant can be offered with specific capital costs up to 20 percent lower than the combined cycle plant, and with competing efficiency. Compared to a combined cycle plant, the CHAT plant offers lower emissions (due to air humidification) and other significant operating advantages with regard to start-up time and costs, better efficiency at part load, lower power degradation at higher ambient temperatures, and simpler operations and maintenance due to elimination of the complexities and costs associated with steam production. The CHAT plant also integrates very effectively with coal gasification and particularly well with the water quench design. This feature has been discussed in previous publications.

  20. The Chat Is Coming from inside the House: An Analysis of Perceived Chat Behavior and Reality

    ERIC Educational Resources Information Center

    Berndt-Morris, Elizabeth; Minnis, Samantha M.

    2014-01-01

    When looking for ways to improve library services, we considered what data sources were readily available to us and how we could harvest and use this data. We investigated three years of chat reference statistics at Central Michigan University, a large research institution, to gain a better understanding of our patrons' chat behavior. We then…

  1. Chat about what matters most: an analysis of chat contributions posted to an outpatient fertility website.

    PubMed

    Van Selm, Martine; Tuil, Wouter; Verhaak, Christianne; Woldringh, Gwendolyn; Kremer, Jan

    2008-12-01

    A content analysis of chat utterances generated by in vitro fertilization (IVF) patients and healthcare professionals revealed that most chat is about the treatment itself and not about childlessness; 56% discloses psychological aspects, 27% physical aspects, and 17% social aspects of the treatment; and that accounts of both external and internal coping behaviors could be identified. PMID:18954274

  2. Drug Facts Chat Day: NIH Experts Answer Students' Drug Questions

    MedlinePlus

    ... Home Current Issue Past Issues Drug Facts Chat Day: NIH Experts Answer Students' Drug Questions Past Issues / ... Drug Abuse during their first Drug Facts Chat Day. Photo courtesy of NIDA The questions poured in… ...

  3. Chat Rooms: Teens Hanging Out on the Web.

    ERIC Educational Resources Information Center

    Purdy, Rebecca; Web Surfers from Central Rappahannock Regional Library

    2002-01-01

    Discusses the use of chat rooms by teens in libraries, including educational reasons and socialization. Considers problems encountered when using chat, including viruses; stresses the need for establishing safety tips; and provides descriptions of five Web sites that allow chat, including instant messaging. (LRW)

  4. You Are There: No Budget for Travel? Try Video Chat

    ERIC Educational Resources Information Center

    Langhorst, Eric

    2009-01-01

    The author discusses how he used video chat as an alternative to a physical trip. Any teacher with an Internet hookup and a $30 webcam can connect with anyone in the world using video chat. Programs like Skype Video and the Google Mail's video chat function make it easy and, best of all, are completely free. The author discusses how to get started…

  5. The Use of Chat in EFL/ESL.

    ERIC Educational Resources Information Center

    d'Eca, Teresa Almeida

    2003-01-01

    Presents the case for using chat (synchronous online communication) in the language classroom from the point of view of a teacher with positive experiences and a balanced awareness of the potential of the medium. Discuses how to integrate chat in language learning, examines the advantages and disadvantages of chat to the language learner, and…

  6. Visualising Knowledge from Chat Debates in Argument Diagrams

    ERIC Educational Resources Information Center

    Salminen, T.; Marttunen, M.; Laurinen, L.

    2010-01-01

    This study investigates whether combining chat discussion and construction of an argument diagram stimulates students to formulate new ideas in practising argumentation. In this study, 16 secondary school students discussed vivisection and gender equality in pairs using both free and structured chat tools. In structured chat, the students selected…

  7. Semiotic Processes in Chat-Based Problem-Solving Situations

    ERIC Educational Resources Information Center

    Schreiber, Christof

    2013-01-01

    This article seeks to illustrate the analysis of episodes of chat sessions based on Charles Sanders Peirce's triadic sign relation. The episodes are from a project called "Math-Chat", which is based on the use of mathematical inscriptions in an experimental setting. What is characteristic of this chat setting is that pupils are required to…

  8. Inhibition of Different Histone Acetyltransferases (HATs) Uncovers Transcription-Dependent and -Independent Acetylation-Mediated Mechanisms in Memory Formation

    ERIC Educational Resources Information Center

    Merschbaecher, Katja; Hatko, Lucyna; Folz, Jennifer; Mueller, Uli

    2016-01-01

    Acetylation of histones changes the efficiency of the transcription processes and thus contributes to the formation of long-term memory (LTM). In our comparative study, we used two inhibitors to characterize the contribution of different histone acetyl transferases (HATs) to appetitive associative learning in the honeybee. For one we applied…

  9. Protein kinase C coordinates histone H3 phosphorylation and acetylation

    PubMed Central

    Darieva, Zoulfia; Webber, Aaron; Warwood, Stacey; Sharrocks, Andrew D

    2015-01-01

    The re-assembly of chromatin following DNA replication is a critical event in the maintenance of genome integrity. Histone H3 acetylation at K56 and phosphorylation at T45 are two important chromatin modifications that accompany chromatin assembly. Here we have identified the protein kinase Pkc1 as a key regulator that coordinates the deposition of these modifications in S. cerevisiae under conditions of replicative stress. Pkc1 phosphorylates the histone acetyl transferase Rtt109 and promotes its ability to acetylate H3K56. Our data also reveal novel cross-talk between two different histone modifications as Pkc1 also enhances H3T45 phosphorylation and this modification is required for H3K56 acetylation. Our data therefore uncover an important role for Pkc1 in coordinating the deposition of two different histone modifications that are important for chromatin assembly. DOI: http://dx.doi.org/10.7554/eLife.09886.001 PMID:26468616

  10. Evaluating the Quality of a Chat Service

    ERIC Educational Resources Information Center

    Arnold, Julie; Kaske, Neal K.

    2005-01-01

    A quantitative study of a university chat reference service (online synchronous) addresses the following research questions: (1) What types of questions are being asked? (2) Who is asking the questions of the service? and (3) Did the customers get correct answers to their questions? All the transcripts (351) from January through August 2002 were…

  11. First Things First: Internet Relay Chat Openings.

    ERIC Educational Resources Information Center

    Rintel, E. Sean; Mulholland, Joan; Pittam, Jeffery

    2001-01-01

    Argues that Internet Relay Chat (IRC) research needs to systematically address links between interaction structures, technological mediation and the instantiation and development of interpersonal relationships. Finds that openings that occur directly following user's entries into public IRC channels are often ambiguous, can disrupt relationship…

  12. Online "Chat" Facilities as Pedagogic Tools

    ERIC Educational Resources Information Center

    Kirkpatrick, Graeme

    2005-01-01

    This article assesses the pedagogic value of the "chat" facility in the Blackboard integrated learning platform. It draws on a case study carried out by the author in the 2001-2 academic session. A level three class in research methods involved students in group working away from class and student feedback indicated that more support was needed to…

  13. Sign Communication in Cri du Chat Syndrome

    ERIC Educational Resources Information Center

    Erlenkamp, Sonja; Kristoffersen, Kristian Emil

    2010-01-01

    This paper presents findings from a study on the use of sign supported Norwegian (SSN) in two individuals with Cri du chat syndrome (CCS). The study gives a first account of some selected aspects of production and intelligibility of SSN in CCS. Possible deviance in manual parameters, in particular inter- and/or intra-subject variation in the use…

  14. Recognizing connotative meaning in military chat communications

    NASA Astrophysics Data System (ADS)

    Budlong, Emily R.; Walter, Sharon M.; Yilmazel, Ozgur

    2009-05-01

    Over the last five to seven years the use of chat in military contexts has expanded quite significantly, in some cases becoming a primary means of communicating time-sensitive data to decision makers and operators. For example, during humanitarian operations with Joint Task Force-Katrina, chat was used extensively to plan, task, and coordinate predeployment and ongoing operations. The informal nature of chat communications allows the relay of far more information than the technical content of messages. Unlike formal documents such as newspapers, chat is often emotive. "Reading between the lines" to understand the connotative meaning of communication exchanges is now feasible, and often important. Understanding the connotative meaning of text is necessary to enable more useful automatic intelligence exploitation. The research project described in this paper was directed at recognizing user connotations of uncertainty and urgency. The project built a matrix of speech features indicative of these categories of meaning, developed data mining software to recognize them, and evaluated the results.

  15. Chatting behavior and patient satisfaction in the outpatient encounter.

    PubMed Central

    Daaleman, Timothy P.; Mueller, Jan

    2004-01-01

    Communication studies suggest that patient sociodemographic factors are embedded within medical encounters and impact patient expectations, judgments, and outcomes, such as satisfaction. Physician chatting has been suggested as one way to enhance patient satisfaction; however, little is known about chatting within the context of the clinical encounter or of the interaction of chatting with patient sociodemographic factors and patient satisfaction. The study's purpose was to determine the prevalence and patterns of chatting, and to examine the association of chatting with patient sociodemographic factors and patient satisfaction with their physician. A convenience sample of adult outpatients from an urban family practice underwent an exit interview. A total of 105 patients participated; 63 (61%) reported chatting from their recent encounter. No sociodemographic differences were observed between patients reporting chatting and those reporting no chatting. Chatting behavior pertaining to the patient's family or friends was the predominant topic, and more nonwhite (30%) than white (13%) patients reported this activity (p<0.001). There was no significant difference in satisfaction scores between patients that reported chatting behavior and those that did not (23.73 vs. 22.79, p=0.076). In addition, there was no difference in patient satisfaction scores for physician personal manner, technical skill, visit explanation, time spent with the physician, and overall visit between the chatting and nonchatting groups. PMID:15160982

  16. Emotional persistence in online chatting communities

    NASA Astrophysics Data System (ADS)

    Garas, Antonios; Garcia, David; Skowron, Marcin; Schweitzer, Frank

    2012-05-01

    How do users behave in online chatrooms, where they instantaneously read and write posts? We analyzed about 2.5 million posts covering various topics in Internet relay channels, and found that user activity patterns follow known power-law and stretched exponential distributions, indicating that online chat activity is not different from other forms of communication. Analysing the emotional expressions (positive, negative, neutral) of users, we revealed a remarkable persistence both for individual users and channels. I.e. despite their anonymity, users tend to follow social norms in repeated interactions in online chats, which results in a specific emotional ``tone'' of the channels. We provide an agent-based model of emotional interaction, which recovers qualitatively both the activity patterns in chatrooms and the emotional persistence of users and channels. While our assumptions about agent's emotional expressions are rooted in psychology, the model allows to test different hypothesis regarding their emotional impact in online communication.

  17. Selective recognition of acetylated histones by bromodomains in transcriptional co-activators

    PubMed Central

    Hassan, Ahmed H.; Awad, Salma; Al-Natour, Zeina; Othman, Samah; Mustafa, Farah; Rizvi, Tahir A.

    2006-01-01

    Bromodomains are present in many chromatin-associated proteins such as the SWI/SNF and RSC chromatin remodelling and the SAGA HAT (histone acetyltransferase) complexes, and can bind to acetylated lysine residues in the N-terminal tails of the histones. Lysine acetylation is a histone modification that forms a stable epigenetic mark on chromatin for bromodomain-containing proteins to dock and in turn regulate gene expression. In order to better understand how bromodomains read the ‘histone code’ and interact with acetylated histones, we have tested the interactions of several bromodomains within transcriptional co-activators with differentially acetylated histone tail peptides and HAT-acetylated histones. Using GST (glutathione S-transferase) pull-down assays, we show specificity of binding of some bromodomains to differentially acetylated H3 and H4 peptides as well as HAT-acetylated histones. Our results reveal that the Swi2/Snf2 bromodomain interacts with various acetylated H3 and H4 peptides, whereas the Gcn5 bromodomain interacts only with acetylated H3 peptides and tetra-acetylated H4 peptides. Additionally we show that the Spt7 bromodomain interacts with acetylated H3 peptides weakly, but not with acetylated H4 peptides. Some bromodomains such as the Bdf1-2 do not interact with most of the acetylated peptides tested. Results of the peptide experiments are confirmed with tests of interactions between these bromodomains and HAT-acetylated histones. Furthermore, we demonstrate that the Swi2/Snf2 bromodomain is important for the binding and the remodelling activity of the SWI/SNF complex on hyperacetylated nucleosomes. The selective recognition of the bromodomains observed in the present study accounts for the broad effects of bromodomain-containing proteins observed on binding to histones. PMID:17049045

  18. TESTING AND ANALYSES OF CHAT AND ASPHALT-CONTAINING CHAT (PRESENTATION)

    EPA Science Inventory

    Granular mine waste are generated from the extraction and beneficiation of lead/zinc minerals. The fine gravel waste, commonly known as chat, in the Tristate Mining District contains elevated levels of lead, zinc and cadmium which can result in potentially serious human health a...

  19. Counseling Children at a Helpline: Chatting or Calling?

    ERIC Educational Resources Information Center

    Fukkink, Ruben; Hermanns, Jo

    2009-01-01

    In a quantitative content analysis, the telephone-based and Web-based support of the Dutch child helpline were studied. Both adult judges and the children themselves indicated that the quality of chat conversations was better than that of telephone conversations. Both the chat and telephone service succeeded in improving children's well-being and…

  20. Chatting It Up Online: Students Talk to a Favorite Author.

    ERIC Educational Resources Information Center

    Livingston, Pamela

    1999-01-01

    Explains procedures for students participating in an author chat using the Internet, based on experiences with children's author Mary Pope Osborne and a third grade class. Discusses equipment needs, how to formulate appropriate questions, and benefits of online chats, including the immediate response time. (LRW)

  1. The Value of Chat Reference Services: A Pilot Study

    ERIC Educational Resources Information Center

    Jacoby, JoAnn; Ward, David; Avery, Susan; Marcyk, Emilia

    2016-01-01

    This article explores student, instructor, and librarian perceptions of chat reference in the context of an introductory composition course. Participants in a mixed-method study responded to an anonymized chat transcript. While student respondents valued speed and efficiency, they were willing to receive instruction and open to questions that…

  2. The Importance of Nonverbal Elements in Online Chat

    ERIC Educational Resources Information Center

    Gajadhar, Joan; Green, John

    2005-01-01

    Communication is often not so much what people write or say but how they write and often what they do not say. Thus, meaning in real-world chat messages depends not only on the words they use but also on how they express meaning through nonverbal cues. Online chat is simple, direct, and unrestrained. While it contains many of the elements of…

  3. Children's Experiences with Chat Support and Telephone Support

    ERIC Educational Resources Information Center

    Fukkink, Ruben G.; Hermanns, Jo M. A.

    2009-01-01

    Background: In line with the wider trend of offering support via the Internet, many counseling and referral services for children have introduced online chat, often in addition to a traditional telephone service. Methods: A comparative study was conducted between the telephone service and the confidential one-on-one online chat service of the…

  4. Perceived safety and teen risk taking in online chat sites.

    PubMed

    McCarty, Cheryl; Prawitz, Aimee D; Derscheid, Linda E; Montgomery, Bette

    2011-03-01

    Framed by theories of adolescent development, this study explored relationships among adolescents' perceptions of chat-site safety, time spent chatting, and risky online behaviors. Tenth graders (N = 139) in rural Midwestern U.S. schools completed surveys. Factor analysis produced three factors each for perception of safety and risk-taking behaviors. Regression analyses revealed that perception of safety factors were useful in predicting online risk-taking behaviors. Teens with more social discomfort and those who thought it was safe to reveal personal information and trust chat-site "friends" were more likely to take risks. As time spent in chat sites increased, so did risk-taking behaviors. Implications for educators and parents are discussed, such as initiation of conversations about safe Internet use, parental participation in chat sites as teens' invited "friends," and school programs to teach safe online practices. PMID:20677982

  5. Leucine-684: A conserved residue of an AMP-acetyl CoA synthetase (AceCS) from Leishmania donovani is involved in substrate recognition, catalysis and acetylation.

    PubMed

    Soumya, Neelagiri; Tandan, Hitendra; Damre, Mangesh V; Gangwal, Rahul P; Sangamwar, Abhay T; Singh, Sushma

    2016-04-15

    AMP-acetyl CoA synthetase (AMP-AceCS) is a key enzyme which catalyzes the activation of acetate to acetyl CoA, an important intermediate at the cross roads of various anabolic and catabolic pathways. Multiple sequence alignment of Leishmania donovani AceCS with other organisms revealed the presence of a highly conserved leucine residue at 684 position which is known to be crucial for acetylation by protein acetyl transferases in other organisms. In an attempt to understand the role of leucine residue at 684 position in L. donovani acetyl CoA synthetase (LdAceCS), it was mutated to proline (P) by site directed mutagenesis. Kinetic analysis of the L684P-LdAceCS mutant revealed approximately two fold increased binding affinity with acetate, whereas fivefold decreased affinity was observed with ATP. There was insignificant change in secondary structure as revealed by CD however, two fold decreased fluorescence intensity was observed at an emission maxima of 340nm. Interestingly, L684P mutation abolished the acetylation of the mutant enzyme indicating the importance of L684 in acetylation of the enzyme. Changes in biochemical parameters of the mutant protein were validated by homology modeling of the wild type and mutant LdAceCS enzyme using Salmonella enterica AceCS crystal structure as template. Our data provides evidence for the role of leucine 684 residue in substrate recognition, catalysis and acetylation of the AceCS enzyme. PMID:26794803

  6. Acetylation of cyclin-dependent kinase 5 is mediated by GCN5

    SciTech Connect

    Lee, Juhyung; Yun, Nuri; Kim, Chiho; Song, Min-Young; Park, Kang-Sik; Oh, Young J.

    2014-04-25

    Highlights: • Cyclin-dependent kinase 5 (CDK5) is present as an acetylated form. • CDK5 is acetylated by GCN5. • CDK5’s acetylation site is mapped at Lys33. • Its acetylation may affect CDK5’s kinase activity. - Abstract: Cyclin-dependent kinase 5 (CDK5), a member of atypical serine/threonine cyclin-dependent kinase family, plays a crucial role in pathophysiology of neurodegenerative disorders. Its kinase activity and substrate specificity are regulated by several independent pathways including binding with its activator, phosphorylation and S-nitrosylation. In the present study, we report that acetylation of CDK5 comprises an additional posttranslational modification within the cells. Among many candidates, we confirmed that its acetylation is enhanced by GCN5, a member of the GCN5-related N-acetyl-transferase family of histone acetyltransferase. Co-immunoprecipitation assay and fluorescent localization study indicated that GCN5 physically interacts with CDK5 and they are co-localized at the specific nuclear foci. Furthermore, liquid chromatography in conjunction with a mass spectrometry indicated that CDK5 is acetylated at Lys33 residue of ATP binding domain. Considering this lysine site is conserved among a wide range of species and other related cyclin-dependent kinases, therefore, we speculate that acetylation may alter the kinase activity of CDK5 via affecting efficacy of ATP coordination.

  7. M4M chat rooms: individual socialization and sexual autonomy.

    PubMed

    Sanders, T C

    2008-04-01

    This paper uses data from twenty-one online and in-person qualitative interviews to examine the meaning and use of chat rooms located on men for men (M4M) websites from the perspectives of men seeking men on the Internet. This research is inspired by recent public health and social sciences literature on gay websites and chat rooms. The data indicate that these online sites help expedite learning about sex and sexuality and, for men who are shy or geographically isolated, to interact with metropolitan gay communities. There is, however, a measure of stigma associated with use of these chat rooms, particularly by men who are older or in coupled relationships. Using these data, the paper argues that M4M chat rooms play a vital role in fostering the sexual autonomy of many men who frequent these venues and that sociologists should devote more study to the complexity of online social interaction. PMID:18432425

  8. Speaking Math: Using Chat in the Multicultural Math Classroom

    ERIC Educational Resources Information Center

    Graham, Janet; Hodgson, Ted

    2008-01-01

    Electronic communication is a powerful tool teachers can leverage to improve learning. In this article, the authors explain how they used chat and discussion forums to improve their mathematics classes, and how others can adapt their strategies across the curriculum.

  9. Who benefits from chatting, and why? The roles of extraversion and supportiveness in online chatting and emotional adjustment.

    PubMed

    Van Zalk, Maarten H W; Branje, Susan J T; Denissen, Jaap; Van Aken, Marcel A G; Meeus, Wim H J

    2011-09-01

    The current study aimed to provide more insight into the role of online chatting in young adults' emotional adjustment. A model was tested that takes into account (a) extraversion of individuals who communicate online, (b) the kind of peers these individuals communicate with online (i.e., online-exclusive peers vs. friends), and (c) the extent to which effects of online chatting on emotional adjustment are mediated by individuals' ability to provide support to others. Young adults (age M = 18.9) filled out questionnaires about themselves and their fellow students at three measurements with a 4-month interval. Results showed that only for less extraverted individuals, chatting with peers found exclusively online directly predicted higher self-esteem and indirectly predicted less depressive symptoms through increases in supportiveness. Thus, results supported a model of social compensation where effects of online chatting with online-exclusive peers improved young adults' emotional adjustment. PMID:21673194

  10. Protein Acetylation and Acetyl Coenzyme A Metabolism in Budding Yeast

    PubMed Central

    Galdieri, Luciano; Zhang, Tiantian; Rogerson, Daniella; Lleshi, Rron

    2014-01-01

    Cells sense and appropriately respond to the physical conditions and availability of nutrients in their environment. This sensing of the environment and consequent cellular responses are orchestrated by a multitude of signaling pathways and typically involve changes in transcription and metabolism. Recent discoveries suggest that the signaling and transcription machineries are regulated by signals which are derived from metabolism and reflect the metabolic state of the cell. Acetyl coenzyme A (CoA) is a key metabolite that links metabolism with signaling, chromatin structure, and transcription. Acetyl-CoA is produced by glycolysis as well as other catabolic pathways and used as a substrate for the citric acid cycle and as a precursor in synthesis of fatty acids and steroids and in other anabolic pathways. This central position in metabolism endows acetyl-CoA with an important regulatory role. Acetyl-CoA serves as a substrate for lysine acetyltransferases (KATs), which catalyze the transfer of acetyl groups to the epsilon-amino groups of lysines in histones and many other proteins. Fluctuations in the concentration of acetyl-CoA, reflecting the metabolic state of the cell, are translated into dynamic protein acetylations that regulate a variety of cell functions, including transcription, replication, DNA repair, cell cycle progression, and aging. This review highlights the synthesis and homeostasis of acetyl-CoA and the regulation of transcriptional and signaling machineries in yeast by acetylation. PMID:25326522

  11. Chat reference service in medical libraries: part 2--Trends in medical school libraries.

    PubMed

    Dee, Cheryl R

    2003-01-01

    An increasing number of medical school libraries offer chat service to provide immediate, high quality information at the time and point of need to students, faculty, staff, and health care professionals. Part 2 of Chat Reference Service in Medical Libraries presents a snapshot of the current trends in chat reference service in medical school libraries. In late 2002, 25 (21%) medical school libraries provided chat reference. Trends in chat reference services in medical school libraries were compiled from an exploration of medical school library Web sites and informal correspondence from medical school library personnel. Many medical libraries are actively investigating and planning new chat reference services, while others have decided not to pursue chat reference at this time. Anecdotal comments from medical school library staff provide insights into chat reference service. PMID:12723811

  12. The world of protein acetylation.

    PubMed

    Drazic, Adrian; Myklebust, Line M; Ree, Rasmus; Arnesen, Thomas

    2016-10-01

    Acetylation is one of the major post-translational protein modifications in the cell, with manifold effects on the protein level as well as on the metabolome level. The acetyl group, donated by the metabolite acetyl-coenzyme A, can be co- or post-translationally attached to either the α-amino group of the N-terminus of proteins or to the ε-amino group of lysine residues. These reactions are catalyzed by various N-terminal and lysine acetyltransferases. In case of lysine acetylation, the reaction is enzymatically reversible via tightly regulated and metabolism-dependent mechanisms. The interplay between acetylation and deacetylation is crucial for many important cellular processes. In recent years, our understanding of protein acetylation has increased significantly by global proteomics analyses and in depth functional studies. This review gives a general overview of protein acetylation and the respective acetyltransferases, and focuses on the regulation of metabolic processes and physiological consequences that come along with protein acetylation. PMID:27296530

  13. Acetyl-L-carnitine restores choline acetyltransferase activity in the hippocampus of rats with partial unilateral fimbria-fornix transection.

    PubMed

    Piovesan, P; Quatrini, G; Pacifici, L; Taglialatela, G; Angelucci, L

    1995-02-01

    Transection of the fimbria-fornix bundle in adult rats results in degeneration of the septohippocampal cholinergic pathway, reminiscent of that occurring in aging as well as Alzheimer disease. We report here a study of the effect of a treatment with acetyl-L-carnitine (ALCAR) in three-month-old Fischer 344 rats bearing a partial unilateral fimbria-fornix transection. ALCAR is known to ameliorate some morphological and functional disturbances in the aged central nervous system (CNS). We used choline acetyltransferase (ChAT) and acetyl cholinesterase (AChE) as markers of central cholinergic function, and nerve growth factor (NGF) levels as indicative of the trophic regulation of the medio-septal cholinergic system. ChAT and AChE activities were significantly reduced in the hippocampus (HIPP) ipsilateral to the lesion as compared to the contralateral one, while no changes were observed in the septum (SPT), nucleus basalis magnocellularis (NBM) or frontal cortex (FCX). ALCAR treatment restored ChAT activity in the ipsilateral HIPP, while AChE levels were not different from those of untreated animals, and did not affect NGF content in either SPT or HIPP. PMID:7793306

  14. Communication Strategy Use and Negotiation of Meaning in Text Chat and Videoconferencing

    ERIC Educational Resources Information Center

    Zhao, Ying

    2010-01-01

    This study aims at investigating meaning negotiation and communication strategy use among nonnative speakers of English in text chat and videoconferencing. Learners in a Chinese and a Japanese university participated in text chats and videoconferences to discuss culture-related topics using English as the common language. Text chat scripts and…

  15. Opinions of Female Juvenile Delinquents about Their Interactions in Chat Rooms

    ERIC Educational Resources Information Center

    Sanger, Dixie; Long, Amie; Ritzman, Mitzi; Stofer, Keri; Davis, Candy

    2004-01-01

    The purpose of this study was to survey the opinions of 62 adolescent females residing in a correctional facility about their use of the Internet to participate in chat room conversations. Findings indicated that 54 of 62 girls (87.09%), with a mean age of 16.72 years, participated in chat room interactions. Most (n = 47) interacted in chat rooms…

  16. Reviving a Digital Dinosaur: Text-Only Synchronous Online Chats and Peer Tutoring in Communication Centers

    ERIC Educational Resources Information Center

    Schwartzman, Roy

    2013-01-01

    A qualitative and quantitative content analysis was conducted of all text-based synchronous online chats at an oral communication peer tutoring center throughout a semester. As a comparative benchmark, chats at the same university's main library were analyzed over the same time period. The library's chats were much more heavily weighted…

  17. Transcription and the New Functionalism: A Counterproposal to CHILDES' CHAT Conventions.

    ERIC Educational Resources Information Center

    Edwards, Jane A.

    The CHAT transcription standard of the Child Language Data Exchange System (CHILDES), the world's largest computer archive of child language data, is critiqued. CHAT is being considered as a possible standard for the field of child language as a whole. It is argued that CHAT is biased toward three views that are no longer current in the field: (1)…

  18. Online Chat Dependency: The Influence of Social Anxiety

    NASA Astrophysics Data System (ADS)

    Wang, Chih-Chien; Chang, Shu-Chen

    Recent developments in information technology have made it easy for people to “chat” online with others in real time, and many do so regularly. “Virtual” relationships can be attractive, especially for people with social interaction problems in the “real world”. This study examines the influence on online chat dependency of three dimensions of social anxiety: general social situation fear, negative evaluation fear, and novel social situation fear. Participants of this study were 454 college students. The survey results show that negative evaluation fear and general social situation fear are relative to online chat dependency, while novel social situation fear does not seem to be a relevant factor.

  19. Energy Matters: An Invitation to Chat About Clean Tech Markets

    ScienceCinema

    Kauffman, Richard

    2013-05-29

    Do you have questions or ideas about how the U.S. Department of Energy can better move renewable energy technologies from labs to the market, to successful full-scale deployment? Richard Kauffman, newly appointed Senior Advisor to Energy Secretary Steven Chu, and former CEO of Good Energies would like to hear them. **LIVE CHAT EXPIRED**

  20. Interaction Management Strategies on IRC and Virtual Chat Rooms.

    ERIC Educational Resources Information Center

    Altun, Arif

    Internet Relay Chat (IRC) is an electronic medium that combines orthographic form with real time, synchronous transmission in an unregulated global multi-user environment. The orthographic letters mediate the interaction in that users can only access the IRC session through reading and writing; they have no access to any visual representations at…

  1. Energy Matters: An invitation to Chat About Industrial Efficiency

    SciTech Connect

    Hogan, Kathleen

    2011-01-01

    Do you have questions or ideas about how the U.S. Department of Energy can contribute to global competitiveness through industrial efficiency? Dr. Kathleen Hogan would like to hear them. Submit your questions via: Email ( newmedia@hq.doe.gov ) Twitter ( @Energy ) Facebook ( Facebook.com/Energygov ) **LIVE CHAT IS EXPIRED**

  2. Energy Matters: An invitation to Chat About Industrial Efficiency

    ScienceCinema

    Hogan, Kathleen

    2013-05-29

    Do you have questions or ideas about how the U.S. Department of Energy can contribute to global competitiveness through industrial efficiency? Dr. Kathleen Hogan would like to hear them. Submit your questions via: Email ( newmedia@hq.doe.gov ) Twitter ( @Energy ) Facebook ( Facebook.com/Energygov ) **LIVE CHAT IS EXPIRED**

  3. Astronaut Thagard and fellow Mir 18 crewmembers chat at JSC

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Norman E. Thagard, right, chats with two Russian cosmonauts with whom he will be launched into space early next year for a three month mission. Designated Mir 18, the mission aboard the Russian space station will include Mir 18 crew members Genn

  4. Energy Matters: An Invitation to Chat About Clean Tech Markets

    SciTech Connect

    Kauffman, Richard

    2011-01-01

    Do you have questions or ideas about how the U.S. Department of Energy can better move renewable energy technologies from labs to the market, to successful full-scale deployment? Richard Kauffman, newly appointed Senior Advisor to Energy Secretary Steven Chu, and former CEO of Good Energies would like to hear them. **LIVE CHAT EXPIRED**

  5. Constructing Sexuality and Identity in an Online Teen Chat Room

    ERIC Educational Resources Information Center

    Subrahmanyam, K.; Greenfield, P. M.; Tynes, B.

    2004-01-01

    In this article, we propose that adolescents' online interactions are both a literal and a metaphoric screen for representing major adolescent developmental issues, such as sexuality and identity. Because of the public nature of Internet chat rooms, they provide an open window into the expression of adolescent concerns. Our study utilizes this…

  6. Metaphors of Synchrony: Emergence and Differentiation of Online Chat Devices

    ERIC Educational Resources Information Center

    Latzko-Toth, Guillaume

    2010-01-01

    Through a detailed account of the history of online chat devices, this article shows the emergence, over time, of two distinct interactional formats underlying these social media. They may be captured by two generic metaphors of synchrony: "conference" (a gathering in a virtual place where unfocused interactions and group sociability occur) and…

  7. Urinary mutagenicity and N-acetylation phenotype in textile industry workers exposed to arylamines

    SciTech Connect

    Sinues, B.; Perez, J.; Bernal, M.L.; Saenz, M.A.; Lanuza, J.; Bartolome, M. )

    1992-09-15

    Primary aromatic amines have been identified epidemiologically as human carcinogens. It has been suggested that the target organ affected by aromatic amines is dependent on the rate of metabolic activation. Epidemiological studies have shown an association between low acetyl transferase activity and bladder cancer risk. On this basis, our working hypothesis was that the slow acetylators could follow in a higher extent the metabolic pathway independent of N-acetylation, leading to the excretion of conjugates of electrophyles with glucuronic acid. The instability of these glucuronides could be responsible for the association between arylamine-induced bladder cancer and slow acetylator phenotype. A total of 153 individuals were included in this study: 70 exposed to arylamines (working in textile industry) and 83 nonexposed. The following parameters were determined in urine: mutagenic index in the absence of metabolic activation, S9; mutagenic index in the presence of S9; and the mutagenic index after incubation of the urine with beta-glucuronidase. All individuals were phenotyped according to their capacity of N-acetylation by using isoniazid as drug test. The results show that the mutagenic index after incubation of the urine with beta-glucuronidase is statistically higher in exposed subjects when compared with nonexposed individuals (P less than 0.001), this parameter being statistically higher among exposed subjects who were slow acetylators than among rapid metabolizers, independent of the fact that they were smokers or nonsmokers. There were no significant differences between groups for the mutagenicity in urine not incubated with beta-glucuronidase.

  8. Functional Dissection of the Bipartite Active Site of the Class I Coenzyme A (CoA)-Transferase Succinyl-CoA:Acetate CoA-Transferase.

    PubMed

    Murphy, Jesse R; Mullins, Elwood A; Kappock, T Joseph

    2016-01-01

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates <3 Å apart. In this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analog dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analog of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. The ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA. PMID:27242998

  9. Functional Dissection of the Bipartite Active Site of the Class I Coenzyme A (CoA)-Transferase Succinyl-CoA:Acetate CoA-Transferase

    PubMed Central

    Murphy, Jesse R.; Mullins, Elwood A.; Kappock, T. Joseph

    2016-01-01

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates <3 Å apart. In this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analog dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analog of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. The ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA. PMID:27242998

  10. Functional dissection of the bipartite active site of the class I coenzyme A (CoA)-transferase succinyl-CoA:acetate CoA-transferase

    NASA Astrophysics Data System (ADS)

    Murphy, Jesse; Mullins, Elwood; Kappock, T.

    2016-05-01

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates less than 3 Å apart. In this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analogue dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analogue of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. The ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA.

  11. Glycosyl transferases in chondroitin sulphate biosynthesis. Effect of acceptor structure on activity.

    PubMed Central

    Gundlach, M W; Conrad, H E

    1985-01-01

    The D-glucuronosyl (GlcA)- and N-acetyl-D-galactosaminyl (GalNAc)-transferases involved in chondroitin sulphate biosynthesis were studied in a microsomal preparation from chick-embryo chondrocytes. Transfer of GlcA and GalNAc from their UDP derivatives to 3H-labelled oligosaccharides prepared from chondroitin sulphate and hyaluronic acid was assayed by h.p.l.c. of the reaction mixture. Conditions required for maximal activities of the two enzymes were remarkably similar. Activities were stimulated 3.5-6-fold by neutral detergents. Both enzymes were completely inhibited by EDTA and maximally stimulated by MnCl2 or CoCl2. MgCl2 neither stimulated nor inhibited. The GlcA transferase showed a sharp pH optimum between pH5 and 6, whereas the GalNAc transferase gave a broad optimum from pH 5 to 8. At pH 7 under optimal conditions, the GalNAc transferase gave a velocity that was twice that of the GlcA transferase. Oligosaccharides prepared from chondroitin 4-sulphate and hyaluronic acid were almost inactive as acceptors for both enzymes, whereas oligosaccharides from chondroitin 6-sulphate and chondroitin gave similar rates that were 70-80-fold higher than those observed with the endogenous acceptors. Oligosaccharide acceptors with degrees of polymerization of 6 or higher gave similar Km and Vmax. values, but the smaller oligosaccharides were less effective acceptors. These results are discussed in terms of the implications for regulation of the overall rates of the chain-elongation fractions in chondroitin sulphate synthesis in vivo. PMID:3921015

  12. Effect of glutathione S-transferase M1 polymorphisms on biomarkers of exposure and effects.

    PubMed Central

    Srám, R J

    1998-01-01

    Genotypes responsible for interindividual differences in ability to activate or detoxify genotoxic agents are recognized as biomarkers of susceptibility. Among the most studied genotypes are human glutathione transferases. The relationship of genetic susceptibility to biomarkers of exposure and effects was studied especially in relation to the genetic polymorphism of glutathione S-transferase M1 (GSTM1). For this review papers reporting the effect of GSTM1 genotype on DNA adducts, protein adducts, urine mutagenicity, Comet assay parameters, chromosomal aberrations, sister chromatid exchanges (SCE), micronuclei, and hypoxanthine-guanine phosphoribosyl transferase mutations were assessed. Subjects in groups occupationally exposed to polycyclic aromatic hydrocarbons, benzidine, pesticides, and 1,3-butadiene were included. As environmentally exposed populations, autopsy donors, coal tar-treated patients, smokers, nonsmokers, mothers, postal workers, and firefighters were followed. From all biomarkers the effect of GSTM1 and N-acetyl transferase 2 was seen in coke oven workers on mutagenicity of urine and of glutathione S-transferase T1 on the chromosomal aberrations in subjects from 1,3-butadiene monomer production units. Effects of genotypes on DNA adducts were found from lung tissue of autopsy donors and from placentas of mothers living in an air-polluted region. The GSTM1 genotype affected mutagenicity of urine in smokers and subjects from polluted regions, protein adducts in smokers, SCE in smokers and nonsmokers, and Comet assay parameters in postal workers. A review of all studies on GSTM1 polymorphisms suggests that research probably has not reached the stage where results can be interpreted to formulate preventive measures. The relationship between genotypes and biomarkers of exposure and effects may provide an important guide to the risk assessment of human exposure to mutagens and carcinogens. PMID:9539016

  13. Properties of succinyl-coenzyme A:D-citramalate coenzyme A transferase and its role in the autotrophic 3-hydroxypropionate cycle of Chloroflexus aurantiacus.

    PubMed

    Friedmann, Silke; Alber, Birgit E; Fuchs, Georg

    2006-09-01

    The phototrophic bacterium Chloroflexus aurantiacus uses the 3-hydroxypropionate cycle for autotrophic CO(2) fixation. This cycle starts with acetyl-coenzyme A (CoA) and produces glyoxylate. Glyoxylate is an unconventional cell carbon precursor that needs special enzymes for assimilation. Glyoxylate is combined with propionyl-CoA to beta-methylmalyl-CoA, which is converted to citramalate. Cell extracts catalyzed the succinyl-CoA-dependent conversion of citramalate to acetyl-CoA and pyruvate, the central cell carbon precursor. This reaction is due to the combined action of enzymes that were upregulated during autotrophic growth, a coenzyme A transferase with the use of succinyl-CoA as the CoA donor and a lyase cleaving citramalyl-CoA to acetyl-CoA and pyruvate. Genomic analysis identified a gene coding for a putative coenzyme A transferase. The gene was heterologously expressed in Escherichia coli and shown to code for succinyl-CoA:d-citramalate coenzyme A transferase. This enzyme, which catalyzes the reaction d-citramalate + succinyl-CoA --> d-citramalyl-CoA + succinate, was purified and studied. It belongs to class III of the coenzyme A transferase enzyme family, with an aspartate residue in the active site. The homodimeric enzyme composed of 44-kDa subunits was specific for succinyl-CoA as a CoA donor but also accepted d-malate and itaconate instead of d-citramalate. The CoA transferase gene is part of a cluster of genes which are cotranscribed, including the gene for d-citramalyl-CoA lyase. It is proposed that the CoA transferase and the lyase catalyze the last two steps in the glyoxylate assimilation route. PMID:16952935

  14. Three CoA Transferases Involved in the Production of Short Chain Fatty Acids in Porphyromonas gingivalis

    PubMed Central

    Sato, Mitsunari; Yoshida, Yasuo; Nagano, Keiji; Hasegawa, Yoshiaki; Takebe, Jun; Yoshimura, Fuminobu

    2016-01-01

    Butyryl-CoA:acetate CoA transferase, which produces butyrate and acetyl-CoA from butyryl-CoA and acetate, is responsible for the final step of butyrate production in bacteria. This study demonstrates that in the periodontopathogenic bacterium Porphyromonas gingivalis this reaction is not catalyzed by PGN_1171, previously annotated as butyryl-CoA:acetate CoA transferase, but by three distinct CoA transferases, PGN_0725, PGN_1341, and PGN_1888. Gas chromatography/mass spectrometry (GC-MS) and spectrophotometric analyses were performed using crude enzyme extracts from deletion mutant strains and purified recombinant proteins. The experiments revealed that, in the presence of acetate, PGN_0725 preferentially utilized butyryl-CoA rather than propionyl-CoA. By contrast, this preference was reversed in PGN_1888. The only butyryl-CoA:acetate CoA transferase activity was observed in PGN_1341. Double reciprocal plots revealed that all the reactions catalyzed by these enzymes follow a ternary-complex mechanism, in contrast to previously characterized CoA transferases. GC-MS analysis to determine the concentrations of short chain fatty acids (SCFAs) in culture supernatants of P. gingivalis wild type and mutant strains revealed that PGN_0725 and PGN_1888 play a major role in the production of butyrate and propionate, respectively. Interestingly, a triple deletion mutant lacking PGN_0725, PGN_1341, and PGN_1888 produced low levels of SCFAs, suggesting that the microorganism contains CoA transferase(s) in addition to these three enzymes. Growth rates of the mutant strains were mostly slower than that of the wild type, indicating that many carbon compounds produced in the SCFA synthesis appear to be important for the biological activity of this microorganism. PMID:27486457

  15. Three CoA Transferases Involved in the Production of Short Chain Fatty Acids in Porphyromonas gingivalis.

    PubMed

    Sato, Mitsunari; Yoshida, Yasuo; Nagano, Keiji; Hasegawa, Yoshiaki; Takebe, Jun; Yoshimura, Fuminobu

    2016-01-01

    Butyryl-CoA:acetate CoA transferase, which produces butyrate and acetyl-CoA from butyryl-CoA and acetate, is responsible for the final step of butyrate production in bacteria. This study demonstrates that in the periodontopathogenic bacterium Porphyromonas gingivalis this reaction is not catalyzed by PGN_1171, previously annotated as butyryl-CoA:acetate CoA transferase, but by three distinct CoA transferases, PGN_0725, PGN_1341, and PGN_1888. Gas chromatography/mass spectrometry (GC-MS) and spectrophotometric analyses were performed using crude enzyme extracts from deletion mutant strains and purified recombinant proteins. The experiments revealed that, in the presence of acetate, PGN_0725 preferentially utilized butyryl-CoA rather than propionyl-CoA. By contrast, this preference was reversed in PGN_1888. The only butyryl-CoA:acetate CoA transferase activity was observed in PGN_1341. Double reciprocal plots revealed that all the reactions catalyzed by these enzymes follow a ternary-complex mechanism, in contrast to previously characterized CoA transferases. GC-MS analysis to determine the concentrations of short chain fatty acids (SCFAs) in culture supernatants of P. gingivalis wild type and mutant strains revealed that PGN_0725 and PGN_1888 play a major role in the production of butyrate and propionate, respectively. Interestingly, a triple deletion mutant lacking PGN_0725, PGN_1341, and PGN_1888 produced low levels of SCFAs, suggesting that the microorganism contains CoA transferase(s) in addition to these three enzymes. Growth rates of the mutant strains were mostly slower than that of the wild type, indicating that many carbon compounds produced in the SCFA synthesis appear to be important for the biological activity of this microorganism. PMID:27486457

  16. Acetyl transfer in arylamine metabolism

    PubMed Central

    Booth, J.

    1966-01-01

    1. N-Hydroxyacetamidoaryl compounds (hydroxamic acids) are metabolites of arylamides, and an enzyme that transfers the acetyl group from these derivatives to arylamines has been found in rat tissues. The reaction products were identified by thin-layer chromatography and a spectrophotometric method, with 4-amino-azobenzene as acetyl acceptor, was used to measure enzyme activity. 2. The acetyltransferase was in the soluble fraction of rat liver, required a thiol for maximum activity and had a pH optimum between 6·0 and 7·5. 3. The soluble fractions of various rat tissues showed decreasing activity in the following order: liver, adrenal, kidney, lung, spleen, testis, heart; brain was inactive. 4. With the exception of aniline and aniline derivatives all the arylamines tested were effective as acetyl acceptors but aromatic compounds with side-chain amino groups were inactive. 5. The N-hydroxyacetamido derivatives of 2-naphthylamine, 4-amino-biphenyl and 2-aminofluorene were active acetyl donors but N-hydroxyacetanilide showed only slight activity. Acetyl-CoA was not a donor. 6. Some properties of the enzyme are compared with those of other acetyltransferases. PMID:5969287

  17. Fatal Intoxication with Acetyl Fentanyl.

    PubMed

    Cunningham, Susan M; Haikal, Nabila A; Kraner, James C

    2016-01-01

    Among the new psychoactive substances encountered in forensic investigations is the opioid, acetyl fentanyl. The death of a 28-year-old man from recreational use of this compound is reported. The decedent was found in the bathroom of his residence with a tourniquet secured around his arm and a syringe nearby. Postmortem examination findings included marked pulmonary and cerebral edema and needle track marks. Toxicological analysis revealed acetyl fentanyl in subclavian blood, liver, vitreous fluid, and urine at concentrations of 235 ng/mL, 2400 ng/g, 131 ng/mL, and 234 ng/mL, respectively. Acetyl fentanyl was also detected in the accompanying syringe. Death was attributed to recreational acetyl fentanyl abuse, likely through intravenous administration. The blood acetyl fentanyl concentration is considerably higher than typically found in fatal fentanyl intoxications. Analysis of this case underscores the need for consideration of a wide range of compounds with potential opioid-agonist activity when investigating apparent recreational drug-related deaths. PMID:26389815

  18. Location based chat application for iPhone

    NASA Astrophysics Data System (ADS)

    Rana, Pradeep

    With the increasing use of mobile devices everywhere in the world, there is a lack of social interaction between people. The objective of this thesis project is to create a location based chat application, which will help users to interact with other people around them. It will provide an opportunity to meet people when someone visits a new place. The app will use GPS coordinates of the user and will show him a list of other users based on his location. The user can then choose any of the other users from the list and start chatting with them. This app will consist of a frontend and backend. The frontend will be an iOS application and the backend will be a PHP/MYSQL server.

  19. Astronaut Jean-Francois Clervoy chats with STS-66 crewmates

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Astronaut Jean-Francois Clervoy (center), STS-66 international mission specialist, chats with payload crew mates during a training session on emergency egress procedures. Wearing training versions of the launch and entry suits, the crew members are, left to right, Scott E. Parazynski, Joseph P. Tanner, Clervoy and Ellen Ochoa. Ochoa is the payload commander, Tanner and Parazynski are NASA mission specialists and Clervoy represents the European Space Agency (ESA) as a mission specialist.

  20. Oxygen-dependent acetylation and dimerization of the corepressor CtBP2 in neural stem cells

    SciTech Connect

    Karaca, Esra; Lewicki, Jakub; Hermanson, Ola

    2015-03-01

    The transcriptional corepressor CtBP2 is essential for proper development of the nervous system. The factor exerts its repression by interacting in complexes with chromatin-modifying factors such as histone deacetylases (HDAC) 1/2 and the histone demethylase LSD1/KDM1. Notably, the histone acetyl transferase p300 acetylates CtBP2 and this is an important regulatory event of the activity and subcellular localization of the protein. We recently demonstrated an essential role for CtBPs as sensors of microenvironmental oxygen levels influencing the differentiation potential of neural stem cells (NSCs), but it is not known whether oxygen levels influence the acetylation levels of CtBP factors. Here we show by using proximity ligation assay (PLA) that CtBP2 acetylation levels increased significantly in undifferentiated, proliferating NSCs under hypoxic conditions. CtBP2 interacted with the class III HDAC Sirt1 but this interaction was unaltered in hypoxic conditions, and treatment with the Sirt1 inhibitor Ex527 did not result in any significant change in total CtBP2 acetylation levels. Instead, we revealed a significant decrease in PLA signal representing CtBP2 dimerization in NSCs under hypoxic conditions, negatively correlating with the acetylation levels. Our results suggest that microenvironmental oxygen levels influence the dimerization and acetylation levels, and thereby the activity, of CtBP2 in proliferating NSCs.

  1. Sirt1 physically interacts with Tip60 and negatively regulates Tip60-mediated acetylation of H2AX

    SciTech Connect

    Yamagata, Kazutsune; Kitabayashi, Issay

    2009-12-25

    Sirt1 appear to be NAD(+)-dependent deacetylase that deacetylates histones and several non-histone proteins. In this study, we identified Sirt1 as a physical interaction partner of Tip60, which is a mammalian MYST-type histone acetyl-transferase that specifically acetylates histones H2A and H4. Although Tip60 also acetylates DNA damage-specific histone H2A variant H2AX in response to DNA damage, which is a process required for appropriate DNA damage response, overexpression of Sirt1 represses Tip60-mediated acetylation of H2AX. Furthermore, Sirt1 depletion by RNAi causes excessive acetylation of H2AX, and enhances accumulation of {gamma}-ray irradiation-induced MDC1, BRCA1, and Rad51 foci in nuclei. These findings suggest that Sirt1 functions as negative regulator of Tip60-mediated acetylation of H2AX. Moreover, Sirt1 deacetylates an acetylated Tip60 in response to DNA damage and stimulates proteasome-dependent Tip60 degradation in vivo, suggesting that Sirt1 negatively regulates the protein level of Tip60 in vivo. Sirt1 may thus repress excessive activation of the DNA damage response and Rad51-homologous recombination repair by suppressing the function of Tip60.

  2. A Cooperative Human-Adaptive Traffic Simulation (CHATS)

    NASA Technical Reports Server (NTRS)

    Phillips, Charles T.; Ballin, Mark G.

    1999-01-01

    NASA is considering the development of a Cooperative Human-Adaptive Traffic Simulation (CHATS), to examine and evaluate performance of the National Airspace System (NAS) as the aviation community moves toward free flight. CHATS will be specifically oriented toward simulating strategic decision-making by airspace users and by the service provider s traffic management personnel, within the context of different airspace and rules assumptions. It will use human teams to represent these interests and make decisions, and will rely on computer modeling and simulation to calculate the impacts of these decisions. The simulation objectives will be to examine: 1. evolution of airspace users and the service provider s strategies, through adaptation to new operational environments; 2. air carriers competitive and cooperative behavior; 3. expected benefits to airspace users and the service provider as compared to the current NAS; 4. operational limitations of free flight concepts due to congestion and safety concerns. This paper describes an operational concept for CHATS, and presents a high-level functional design which would utilize a combination of existing and new models and simulation capabilities.

  3. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica.

    PubMed

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  4. Acetylated α-Tubulin Regulated by N-Acetyl-Seryl-Aspartyl-Lysyl-Proline(Ac-SDKP) Exerts the Anti-fibrotic Effect in Rat Lung Fibrosis Induced by Silica

    PubMed Central

    Xiaojun, Wang; Yan, Liu; Hong, Xu; Xianghong, Zhang; Shifeng, Li; Dingjie, Xu; Xuemin, Gao; Lijuan, Zhang; Bonan, Zhang; Zhongqiu, Wei; Ruimin, Wang; Brann, Darrell; Fang, Yang

    2016-01-01

    Silicosis is the most serious occupational disease in China. The objective of this study was to screen various proteins related to mechanisms of the pathogenesis of silicosis underlying the anti-fibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) using proteomic profile analysis. We also aimed to explore a potential mechanism of acetylated α-tubulin (α-Ac-Tub) regulation by Ac-SDKP. Two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to assess the different protein expression profiles between control and silicosis rats treated with or without Ac-SDKP. Twenty-nine proteins were identified to be potentially involved in the progression of silicosis and the anti-fibrotic effect of Ac-SDKP. Our current study finds that 1) the lost expression of Ac-Tub-α may be a new mechanism in rat silicosis; 2) treatment of silicotic rats with N-acetyl-Seryl-Aspartyl-Lysyl-Proline (Ac-SDKP) inhibits myofibroblast differentiation and collagen deposition accompanied by stabilizing the expression of α-Ac-Tub in vivo and in vitro, which is related with deacetylase family member 6 (HDAC6) and α-tubulin acetyl transferase (α-TAT1). Our data suggest that α-Ac-Tub regulation by Ac-SDKP may potentially be a new anti-fibrosis mechanism. PMID:27577858

  5. Roles for glutathione transferases in antioxidant recycling

    PubMed Central

    Dixon, David P; Steel, Patrick G

    2011-01-01

    Uniquely among the plant glutathione transferases, two classes possess a catalytic cysteine capable of performing glutathione-dependent reductions. These are the dehydroascorbate reductases (DHARs) and the lambda-class glutathione transferases (GSTLs). Using immobilized GSTLs probed with crude plant extracts we have identified flavonols as high affinity ligands and subsequently demonstrated a novel glutathione-dependent role for these enzymes in recycling oxidized quercetin. By comparing the activities of DHARs and GSTLs we now propose a unified catalytic mechanism that suggests oxidized anthocyanidins and tocopherols may be alternative polyphenolic substrates of GSTLs. PMID:21778824

  6. Bacterial protein acetylation: new discoveries unanswered questions.

    PubMed

    Wolfe, Alan J

    2016-05-01

    Nε-acetylation is emerging as an abundant post-translational modification of bacterial proteins. Two mechanisms have been identified: one is enzymatic, dependent on an acetyltransferase and acetyl-coenzyme A; the other is non-enzymatic and depends on the reactivity of acetyl phosphate. Some, but not most, of those acetylations are reversed by deacetylases. This review will briefly describe the current status of the field and raise questions that need answering. PMID:26660885

  7. Properties of succinyl-coenzyme A:L-malate coenzyme A transferase and its role in the autotrophic 3-hydroxypropionate cycle of Chloroflexus aurantiacus.

    PubMed

    Friedmann, Silke; Steindorf, Astrid; Alber, Birgit E; Fuchs, Georg

    2006-04-01

    The 3-hydroxypropionate cycle has been proposed to operate as the autotrophic CO2 fixation pathway in the phototrophic bacterium Chloroflexus aurantiacus. In this pathway, acetyl coenzyme A (acetyl-CoA) and two bicarbonate molecules are converted to malate. Acetyl-CoA is regenerated from malyl-CoA by L-malyl-CoA lyase. The enzyme forming malyl-CoA, succinyl-CoA:L-malate coenzyme A transferase, was purified. Based on the N-terminal amino acid sequence of its two subunits, the corresponding genes were identified on a gene cluster which also contains the gene for L-malyl-CoA lyase, the subsequent enzyme in the pathway. Both enzymes were severalfold up-regulated under autotrophic conditions, which is in line with their proposed function in CO2 fixation. The two CoA transferase genes were cloned and heterologously expressed in Escherichia coli, and the recombinant enzyme was purified and studied. Succinyl-CoA:L-malate CoA transferase forms a large (alphabeta)n complex consisting of 46- and 44-kDa subunits and catalyzes the reversible reaction succinyl-CoA + L-malate --> succinate + L-malyl-CoA. It is specific for succinyl-CoA as the CoA donor but accepts L-citramalate instead of L-malate as the CoA acceptor; the corresponding d-stereoisomers are not accepted. The enzyme is a member of the class III of the CoA transferase family. The demonstration of the missing CoA transferase closes the last gap in the proposed 3-hydroxypropionate cycle. PMID:16547052

  8. Chat Widgets on the Library Website: Help at the Point of Need

    ERIC Educational Resources Information Center

    Meier, John J.

    2008-01-01

    This article describes the use of chat widgets on library websites and how it affects daily work and organizational culture. The use of chat widgets can be as simple or confusing as the website itself, but it helps to make choices that fit the web design and the organizational culture. Too often change is driven from outside, which can make…

  9. Tutorial Chat: A Case Study of Synchronous Communication in a Learning Environment

    ERIC Educational Resources Information Center

    Rutter, Malcolm

    2006-01-01

    This case study describes the use of a web-based synchronous chat application, run during computing tutorials. The chat room was moderated by a paid demonstrator, who assisted and encouraged students whenever possible. Most of the discussion was banter, which acted as a lubricant for relevant factual communication. Students were permitted a degree…

  10. Synchronous CMC and Pragmatic Development: Effects of Oral and Written Chat

    ERIC Educational Resources Information Center

    Sykes, Julie M.

    2005-01-01

    This study systematically examines the strength of the connection between synchronous CMC and pragmatic instruction by measuring the effects of three types of synchronous group discussion (written chat [WC], oral chat [OC], and traditional face-to-face [FF] discussion) on the acquisition of the speech act (refusals of an invitation) in the target…

  11. Evaluating a Chat Reference Service at the University of South Alabama's Baugh Biomedical Library

    ERIC Educational Resources Information Center

    Clanton, Clista C.; Staggs, Geneva B.; Williams, Thomas L.

    2006-01-01

    The University of South Alabama's Baugh Biomedical Library recently initiated a chat reference service targeted at distance education students in the biomedical sciences. After one year of service, the library conducted an evaluation of the chat reference to assess the success of this mode of reference service. Both traditional reference and…

  12. Association between Fatigue and Autistic Symptoms in Children with Cri du Chat Syndrome

    ERIC Educational Resources Information Center

    Claro, Anthony; Cornish, Kim; Gruber, Reut

    2011-01-01

    In the current study, the authors examined whether the fatigue level of children diagnosed with cri du chat syndrome was associated with the expression of autistic symptoms. Sixty-nine children with cri du chat syndrome were compared with 47 children with moderate to severe intellectual disabilities who did not differ on intellectual severity.…

  13. Chat Reference Training after One Decade: The Results of a National Survey of Academic Libraries

    ERIC Educational Resources Information Center

    Devine, Christopher; Paladino, Emily Bounds; Davis, John A.

    2011-01-01

    The first comprehensive national survey of all academic libraries in the United States which were conducting chat reference service was carried out to determine: what practices were being used to prepare personnel for chat reference service, what competencies were being taught, how and why training practices may have changed over time, and what…

  14. R-U-Typing-2-Me? Evolving a Chat Tool to Increase Understanding in Learning Activities

    ERIC Educational Resources Information Center

    Fuks, Hugo; Pimentel, Mariano; Lucena, Carlos Jose Pereira de

    2006-01-01

    Very often, when using a chat tool where more than one participant is talking simultaneously, it is difficult to follow the conversation, read all the different messages and work out who is talking to whom about what. This problem has been dubbed "Chat Confusion." This article investigates this problem in debate sessions in an online university…

  15. Visualization of Expert Chat Development in a World of Warcraft Player Group

    ERIC Educational Resources Information Center

    Chen, Mark

    2009-01-01

    This article describes expertise development in a player group in the massively multiplayer online game World of Warcraft using visualization of chat log data. Charts were created to get a general sense of chat trends in a specific player group engaged in "high-end raiding", a 40-person collaborative activity. These charts helped identify patterns…

  16. Synchronous Discussion in Online Courses: A Pedagogical Strategy for Taming the Chat Beast

    ERIC Educational Resources Information Center

    Smith, Craig W.

    2006-01-01

    Many online classes use synchronous communication--chat--as a way to conduct class discussion. However, chat can quickly disintegrate into nonproductive chaos if allowed to flow unchecked. The tools provided by course management systems such as Blackboard provide one solution to this problem by allowing instructors to grant or deny access to…

  17. Potential of Text-Based Internet Chats for Improving Oral Fluency in a Second Language

    ERIC Educational Resources Information Center

    Blake, Christopher

    2009-01-01

    Although a number of studies have reported on the positive effects of Internet chats in the second language classroom, to the best of my knowledge no studies to date have examined the effect of text-based chats on oral fluency development. This exploratory study addressed the above question by examining the oral fluency development of 34 English…

  18. Conversations--and Negotiated Interaction--in Text and Voice Chat Rooms

    ERIC Educational Resources Information Center

    Jepson, Kevin

    2005-01-01

    Despite the expanded use of the Internet for language learning and practice, little attention if any has been given to the quality of interaction among English L2 speakers in conversational text or voice chat rooms. This study explored the patterns of repair moves in synchronous non-native speaker (NNS) text chat rooms in comparison to voice chat…

  19. A Linguistic Analysis of Chat Reference Conversations with 18-24 Year-Old College Students

    ERIC Educational Resources Information Center

    Maness, Jack M.

    2008-01-01

    Thirty-one chat reference conversations were linguistically analyzed, compared to twenty-three instant messaging (IM) conversations held between students, and further correlated to students' satisfaction with the reference interaction. Conversations between librarians and students in chat reference are more formal than those solely involving…

  20. Overlapping Chat's Accessibility Requirements between Students with and without Disabilities Due to the Mobile Limitations

    ERIC Educational Resources Information Center

    Calvo, Rocío; Iglesias, Ana; Moreno, Lourdes

    2014-01-01

    The use of Chats has been extended to mobile-learning (m-learning) environments in the last decade. Students and teachers can communicate in real time and they do not need waiting till their next tutoring date to solve their problems and doubts. However, Chats have many accessibility barriers and many students cannot use this collaborative tool.…

  1. "PolyCAFe"--Automatic Support for the Polyphonic Analysis of CSCL Chats

    ERIC Educational Resources Information Center

    Trausan-Matu, Stefan; Dascalu, Mihai; Rebedea, Traian

    2014-01-01

    Chat conversations and other types of online communication environments are widely used within CSCL educational scenarios. However, there is a lack of theoretical and methodological background for the analysis of collaboration. Manual assessing of non-moderated chat discussions is difficult and time-consuming, having as a consequence that learning…

  2. Methodological Issues in Developing a Multi-Dimensional Coding Procedure for Small-Group Chat Communication

    ERIC Educational Resources Information Center

    Strijbos, Jan-Willem; Stahl, Gerry

    2007-01-01

    In CSCL research, collaboration through chat has primarily been studied in dyadic settings. This article discusses three issues that emerged during the development of a multi-dimensional coding procedure for small-group chat communication: (a) the unit of analysis and unit fragmentation, (b) the reconstruction of the response structure and (c)…

  3. Chronic ethanol consumption induces mitochondrial protein acetylation and oxidative stress in the kidney

    PubMed Central

    Harris, Peter S.; Roy, Samantha R.; Coughlan, Christina; Orlicky, David J.; Liang, Yongliang; Shearn, Colin T.; Roede, James R.; Fritz, Kristofer S.

    2015-01-01

    In this study, we present the novel findings that chronic ethanol consumption induces mitochondrial protein hyperacetylation in the kidney and correlates with significantly increased renal oxidative stress. A major proteomic footprint of alcoholic liver disease (ALD) is an increase in hepatic mitochondrial protein acetylation. Protein hyperacetylation has been shown to alter enzymatic function of numerous proteins and plays a role in regulating metabolic processes. Renal mitochondrial targets of hyperacetylation include numerous metabolic and antioxidant pathways, such as lipid metabolism, oxidative phosphorylation, and amino acid metabolism, as well as glutathione and thioredoxin pathways. Disruption of protein lysine acetylation has the potential to impair renal function through metabolic dysregulation and decreased antioxidant capacity. Due to a significant elevation in ethanol-mediated renal oxidative stress, we highlight the acetylation of superoxide dismutase, peroxiredoxins, glutathione reductase, and glutathione transferase enzymes. Since oxidative stress is a known factor in ethanol-induced nephrotoxicity, we examined biochemical markers of protein hyperacetylation and oxidative stress. Our results demonstrate increased protein acetylation concurrent with depleted glutathione, altered Cys redox potential, and the presence of 4-HNE protein modifications in our 6-week model of early-stage alcoholic nephrotoxicity. These findings support the hypothesis that ethanol metabolism causes an influx of mitochondrial metabolic substrate, resulting in mitochondrial protein hyperacetylation with the potential to impact mitochondrial metabolic and antioxidant processes. PMID:26177469

  4. Small GTP-binding protein Ran is regulated by posttranslational lysine acetylation

    PubMed Central

    de Boor, Susanne; Knyphausen, Philipp; Kuhlmann, Nora; Wroblowski, Sarah; Brenig, Julian; Scislowski, Lukas; Baldus, Linda; Nolte, Hendrik; Krüger, Marcus; Lammers, Michael

    2015-01-01

    Ran is a small GTP-binding protein of the Ras superfamily regulating fundamental cellular processes: nucleo-cytoplasmic transport, nuclear envelope formation and mitotic spindle assembly. An intracellular Ran•GTP/Ran•GDP gradient created by the distinct subcellular localization of its regulators RCC1 and RanGAP mediates many of its cellular effects. Recent proteomic screens identified five Ran lysine acetylation sites in human and eleven sites in mouse/rat tissues. Some of these sites are located in functionally highly important regions such as switch I and switch II. Here, we show that lysine acetylation interferes with essential aspects of Ran function: nucleotide exchange and hydrolysis, subcellular Ran localization, GTP hydrolysis, and the interaction with import and export receptors. Deacetylation activity of certain sirtuins was detected for two Ran acetylation sites in vitro. Moreover, Ran was acetylated by CBP/p300 and Tip60 in vitro and on transferase overexpression in vivo. Overall, this study addresses many important challenges of the acetylome field, which will be discussed. PMID:26124124

  5. Binding of the histone chaperone ASF1 to the CBP bromodomain promotes histone acetylation.

    PubMed

    Das, Chandrima; Roy, Siddhartha; Namjoshi, Sarita; Malarkey, Christopher S; Jones, David N M; Kutateladze, Tatiana G; Churchill, Mair E A; Tyler, Jessica K

    2014-03-25

    The multifunctional Creb-binding protein (CBP) protein plays a pivotal role in many critical cellular processes. Here we demonstrate that the bromodomain of CBP binds to histone H3 acetylated on lysine 56 (K56Ac) with higher affinity than to its other monoacetylated binding partners. We show that autoacetylation of CBP is critical for the bromodomain-H3 K56Ac interaction, and we propose that this interaction occurs via autoacetylation-induced conformation changes in CBP. Unexpectedly, the bromodomain promotes acetylation of H3 K56 on free histones. The CBP bromodomain also interacts with the histone chaperone anti-silencing function 1 (ASF1) via a nearby but distinct interface. This interaction is necessary for ASF1 to promote acetylation of H3 K56 by CBP, indicating that the ASF1-bromodomain interaction physically delivers the histones to the histone acetyl transferase domain of CBP. A CBP bromodomain mutation manifested in Rubinstein-Taybi syndrome has compromised binding to both H3 K56Ac and ASF1, suggesting that these interactions are important for the normal function of CBP. PMID:24616510

  6. Characterization of the mississippian chat in South-central Kansas

    USGS Publications Warehouse

    Watney, W.L.; Guy, W.J.; Byrnes, A.P.

    2001-01-01

    To understand production from low resistivity-high porosity Mississippian chat reservoirs in south-central Kansas it is necessary to understand the nature of deposition and diagenesis, how tectonics is a factor, the lithofacies controls on petrophysical properties, and log response to these properties. The initial mudstones to sponge-spicule wacke-packstones were deposited in transgressive-regressive (T-R) cycles on a shelf to shelf margin setting, resulting in a series of shallowing-upward cycles. Sponge-spicule content appears to increase upward with increasing cycle thickness. After early silicification, inter- and post-Mississippian subaerial exposure resulted in further diagenesis, including sponge-spicule dissolution, vuggy porosity development in moldic-rich rocks, and autobrecciation. Meteoric water infiltration is limited in depth below the exposure surface and in distance downdip into unaltered, cherty Cowley Formation facies. Areas of thicker preserved chat and increased diagenesis can be correlated with structural lineaments and, in some areas, with recurrent basement block movement. Combination of folding or block fault movement prior to or during development of the basal Pennsylvanian unconformity, sponge-spicule concentration, and possibly thickness of overlying bioclastic wacke-grainstones resulted in variable reservoir properties and the creation of pods of production separated by nonproductive cherty dolomite mudstones. These events also resulted in alteration of the depositional cycles to produce a series of lithofacies that exhibit unique petrophysical properties. From bottom to top in a complete cycle seven lithofacies are present: (1) argillaceous dolomite mudstone, (2) argillaceous dolomite mudstone that has chert nodules, (3) clean dolomite mudstone that has nodular chert, (4) nodular to bedded chert, (5) autoclastic chert, (6) autoclastic chert that has clay infill, and (7) bioclastic wacke-grainstone. The uppermost cycle was terminated by

  7. Investigating Histone Acetylation Stoichiometry and Turnover Rate.

    PubMed

    Fan, J; Baeza, J; Denu, J M

    2016-01-01

    Histone acetylation is a dynamic epigenetic modification that functions in the regulation of DNA-templated reactions, such as transcription. This lysine modification is reversibly controlled by histone (lysine) acetyltransferases and deacetylases. Here, we present methods employing isotopic labeling and mass spectrometry (MS) to comprehensively investigate histone acetylation dynamics. Turnover rates of histone acetylation are determined by measuring the kinetics of labeling from (13)C-labeled precursors of acetyl-CoA, which incorporates (13)C-carbon onto histones via the acetyltransferase reaction. Overall histone acetylation states are assessed from complete protease digestion to single amino acids, which is followed by MS analysis. Determination of site-specific acetylation stoichiometry is achieved by chemically acetylating endogenous histones with isotopic acetic anhydride, followed by trypsin digestion and LC-MS analysis. Combining metabolic labeling with stoichiometric analysis permits determination of both acetylation level and acetylation dynamics. When comparing genetic, diet, or environmental perturbations, these methods permit both a global and site-specific evaluation of how histone acetylation is dynamically regulated. PMID:27423860

  8. Purification and characterization of the Oligosaccharyl transferase

    SciTech Connect

    Kapoor, T.M.

    1990-11-01

    Oligosaccharyl transferase was characterized to be a glycoprotein with at least one saccharide unit that had a D-manno or D- glucopyranose configuration with unmodified hydroxy groups at C-3, C-4 and C-6, using a Concanavalin A affinity column. This afforded a 100 fold increase in the transferase purity in the solubilized microsomal sample and also removed over 90% of the microsomal proteins (the cytosolic ones being removed before solubilization). The detergent, N,N-Dimethyldodecylamine N-oxide (LDAO) was used for solubilization and it yielded a system compatible with the assay and the purification steps. An efficient method for detergent extraction without dilution of sample or protein precipitation was also developed.

  9. Mitochondrial Acetylation and Diseases of Aging

    PubMed Central

    Wagner, Gregory R.; Payne, R. Mark

    2011-01-01

    In recent years, protein lysine acetylation has emerged as a prominent and conserved regulatory posttranslational modification that is abundant on numerous enzymes involved in the processes of intermediary metabolism. Well-characterized mitochondrial processes of carbon utilization are enriched in acetyl-lysine modifications. Although seminal discoveries have been made in the basic biology of mitochondrial acetylation, an understanding of how acetylation states influence enzyme function and metabolic reprogramming during pathological states remains largely unknown. This paper will examine our current understanding of eukaryotic acetate metabolism and present recent findings in the field of mitochondrial acetylation biology. The implications of mitochondrial acetylation for the aging process will be discussed, as well as its potential implications for the unique and localized metabolic states that occur during the aging-associated conditions of heart failure and cancer growth. PMID:21437190

  10. A systematic review of the oral and craniofacial manifestations of cri du chat syndrome.

    PubMed

    Corcuera-Flores, José-Ramón; Casttellanos-Cosano, Lizett; Torres-Lagares, Daniel; Serrera-Figallo, María Ángeles; Rodríguez-Caballero, Ángela; Machuca-Portillo, Guillermo

    2016-07-01

    Cri du chat syndrome is an autosomal disorder. Because it affects few people in the population it is considered a rare disease, yet it is one of the most common autosomal chromosomal syndromes in humans. It entails pathognomonic alterations that affect the craniofacial and oral anatomy of patients. The aim of this study is to review these craniofacial and oral abnormalities in patients with Cri du chat syndrome. The PubMed Medline database was searched using two different strategies. First, we used "Dentistry" and "Cri du chat" as keywords; second, we used "Cri du chat" and "craniofacial." Seven articles in which the main orofacial and cranio-skeletal characteristics of patients with Cri du chat syndrome were described were selected according to the inclusion and exclusion criteria. Cri du Chat syndrome entails pathognomonic characteristics in the craniofacial area (epicanthus, short philtrum, and wide nasal bridge), the oral area (mandibular retrognathism and anterior open bite) and the cranial region (alterations at the cranial base angle and a small upper airway). However, more studies on larger samples are needed to specify the orofacial and craniofacial characteristics of patients with Cri du chat syndrome more accurately. Clin. Anat. 29:555-560, 2016. © 2015 Wiley Periodicals, Inc. PMID:26457586

  11. M-CHAT Mexican Version Validity and Reliability and Some Cultural Considerations

    PubMed Central

    Albores-Gallo, Lilia; Roldán-Ceballos, Ofelia; Villarreal-Valdes, Gabriela; Betanzos-Cruz, Blanca Xochitl; Santos-Sánchez, Claudia; Martínez-Jaime, Maria Magdalena; Lemus-Espinosa, Isaac; Hilton, Claudia List

    2012-01-01

    The Modified Checklist for Autism in Toddlers (M-CHAT) questionnaire is a brief measure available in Spanish which needs to be validated for the Mexican population. Parents of children from (1) community with typical development (TD) and (2) psychiatric outpatient unit completed the CBCL/1.5–5 and the Mexican/MM-CHAT-version. The study sample consisted of 456 children (age M = 4.46, SD = 1.12), 74.34% TD children and 26.65% with Autism Spectrum Disorders (ASD). The MM-CHAT mean score for failed key items was higher for the ASD group compared with the TD group. Internal consistency for the Mexican/M-CHAT version was .76 for total score and .70 for the 6 critical items. Correlations between the MM-CHAT and the CBCL/1.5: PDD and Withdrawn subscales and with ADI-R dimensions: B non verbal) and A were high, and were moderate with ADI-R dimensions B1 (verbal) and C The failure rate of the MM-CHAT between the groups did not reproduce all the critical items found in other studies. Although the instrument has good psychometric properties and can be used for screening purposes in primary settings or busy specialized psychiatric clinics, these results support evidence for cultural differences in item responses, making it difficult to compare M-CHAT results internationally. PMID:22811934

  12. A Method to determine lysine acetylation stoichiometries

    SciTech Connect

    Nakayasu, Ernesto S.; Wu, Si; Sydor, Michael A.; Shukla, Anil K.; Weitz, Karl K.; Moore, Ronald J.; Hixson, Kim K.; Kim, Jong Seo; Petyuk, Vladislav A.; Monroe, Matthew E.; Pasa-Tolic, Ljiljana; Qian, Weijun; Smith, Richard D.; Adkins, Joshua N.; Ansong, Charles

    2014-07-21

    A major bottleneck to fully understanding the functional aspects of lysine acetylation is the lack of stoichiometry information. Here we describe a mass spectrometry method using a combination of isotope labeling and detection of a diagnostic fragment ion to determine the stoichiometry of lysine acetylation on proteins globally. Using this technique, we determined the modification occupancy on hundreds of acetylated peptides from cell lysates and cross-validated the measurements via immunoblotting.

  13. Emotion Chat: A Web Chatroom with Emotion Regulation for E-Learners

    NASA Astrophysics Data System (ADS)

    Zheng, Deli; Tian, Feng; Liu, Jun; Zheng, Qinghua; Qin, Jiwei

    In order to compensate for lack of emotion communication between teachers and students in e-learning systems, we have designed and implemented the EmotionChat -- a web chatroom with emotion regulation. EmotionChat perceives e-learners' emotional states based on interactive text. And it recommends resources such as music, cartoons, and mottos to an e-learner when it detects negative emotional states. Meanwhile, it recommends emotion regulation cases to the e-learner's listeners and teachers. The result of our initial experiment shows that EmotionChat can recommend valuable emotion regulation policies for e-learners.

  14. Hello Harlie: Enabling Speech Monitoring Through Chat-Bot Conversations.

    PubMed

    Ireland, David; Atay, Christina; Liddle, Jacki; Bradford, Dana; Lee, Helen; Rushin, Olivia; Mullins, Thomas; Angus, Dan; Wiles, Janet; McBride, Simon; Vogel, Adam

    2016-01-01

    People with neurological conditions such as Parkinson's disease and dementia are known to have difficulties in language and communication. This paper presents initial testing of an artificial conversational agent, called Harlie. Harlie runs on a smartphone and is able to converse with the user on a variety of topics. A description of the application and a sample dialog are provided to illustrate the various roles chat-bots can play in the management of neurological conditions. Harlie can be used for measuring voice and communication outcomes during the daily life of the user, and for gaining information about challenges encountered. Moreover, it is anticipated that she may also have an educational and support role. PMID:27440289

  15. Dan Goldin chats with First Lady Hillary Clinton

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, NASA Administrator Daniel Goldin (right) chats with First Lady Hillary Rodham Clinton and others while waiting for the launch of STS-93. Much attention has been generated over STS-93 due to Commander Eileen M. Collins, the first woman to serve as commander of a Shuttle mission. The primary payload of the five-day mission is the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected to unlock the secrets of supernovae, quasars and black holes. Liftoff of Space Shuttle Columbia is scheduled for 12:36 a.m. EDT July 20.

  16. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  17. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  18. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  19. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  20. 40 CFR 278.3 - Criteria for use of chat in Federally funded transportation projects.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) IN ASPHALT CONCRETE AND PORTLAND CEMENT CONCRETE IN TRANSPORTATION CONSTRUCTION PROJECTS FUNDED IN..., or in epoxy seal; or (b) The chat is used in Portland cement concrete, granular road base,...

  1. Proteomic profiling of lysine acetylation in Pseudomonas aeruginosa reveals the diversity of acetylated proteins.

    PubMed

    Ouidir, Tassadit; Cosette, Pascal; Jouenne, Thierry; Hardouin, Julie

    2015-07-01

    Protein lysine acetylation is a reversible and highly regulated post-translational modification with the well demonstrated physiological relevance in eukaryotes. Recently, its important role in the regulation of metabolic processes in bacteria was highlighted. Here, we reported the lysine acetylproteome of Pseudomonas aeruginosa using a proteomic approach. We identified 430 unique peptides corresponding to 320 acetylated proteins. In addition to the proteins involved in various metabolic pathways, several enzymes contributing to the lipopolysaccharides biosynthesis were characterized as acetylated. This data set illustrated the abundance and the diversity of acetylated lysine proteins in P. aeruginosa and opens opportunities to explore the role of the acetylation in the bacterial physiology. PMID:25900529

  2. A Method to Determine Lysine Acetylation Stoichiometries

    DOE PAGESBeta

    Nakayasu, Ernesto S.; Wu, Si; Sydor, Michael A.; Shukla, Anil K.; Weitz, Karl K.; Moore, Ronald J.; Hixson, Kim K.; Kim, Jong-Seo; Petyuk, Vladislav A.; Monroe, Matthew E.; et al

    2014-01-01

    Lysine acetylation is a common protein posttranslational modification that regulates a variety of biological processes. A major bottleneck to fully understanding the functional aspects of lysine acetylation is the difficulty in measuring the proportion of lysine residues that are acetylated. Here we describe a mass spectrometry method using a combination of isotope labeling and detection of a diagnostic fragment ion to determine the stoichiometry of protein lysine acetylation. Using this technique, we determined the modification occupancy for ~750 acetylated peptides from mammalian cell lysates. Furthermore, the acetylation on N-terminal tail of histone H4 was cross-validated by treating cells with sodiummore » butyrate, a potent deacetylase inhibitor, and comparing changes in stoichiometry levels measured by our method with immunoblotting measurements. Of note we observe that acetylation stoichiometry is high in nuclear proteins, but very low in mitochondrial and cytosolic proteins. In summary, our method opens new opportunities to study in detail the relationship of lysine acetylation levels of proteins with their biological functions.« less

  3. SPOTing Acetyl-Lysine Dependent Interactions

    PubMed Central

    Picaud, Sarah; Filippakopoulos, Panagis

    2015-01-01

    Post translational modifications have been recognized as chemical signals that create docking sites for evolutionary conserved effector modules, allowing for signal integration within large networks of interactions. Lysine acetylation in particular has attracted attention as a regulatory modification, affecting chromatin structure and linking to transcriptional activation. Advances in peptide array technologies have facilitated the study of acetyl-lysine-containing linear motifs interacting with the evolutionary conserved bromodomain module, which specifically recognizes and binds to acetylated sequences in histones and other proteins. Here we summarize recent work employing SPOT peptide technology to identify acetyl-lysine dependent interactions and document the protocols adapted in our lab, as well as our efforts to characterize such bromodomain-histone interactions. Our results highlight the versatility of SPOT methods and establish an affordable tool for rapid access to potential protein/modified-peptide interactions involving lysine acetylation.

  4. Histone Acetylation in Fungal Pathogens of Plants

    PubMed Central

    Jeon, Junhyun; Kwon, Seomun; Lee, Yong-Hwan

    2014-01-01

    Acetylation of histone lysine residues occurs in different organisms ranging from yeast to plants and mammals for the regulation of diverse cellular processes. With the identification of enzymes that create or reverse this modification, our understanding on histone acetylation has expanded at an amazing pace during the last two decades. In fungal pathogens of plants, however, the importance of such modification has only just begun to be appreciated in the recent years and there is a dearth of information on how histone acetylation is implicated in fungal pathogenesis. This review covers the current status of research related to histone acetylation in plant pathogenic fungi and considers relevant findings in the interaction between fungal pathogens and host plants. We first describe the families of histone acetyltransferases and deacetylases. Then we provide the cases where histone acetylation was investigated in the context of fungal pathogenesis. Finally, future directions and perspectives in epigenetics of fungal pathogenesis are discussed. PMID:25288980

  5. A yeast artificial chromosome contig of the critical region for cri-du-chat syndrome

    SciTech Connect

    Goodart, S.A.; Rojas, K.; Overhauser, J.

    1994-11-01

    Cri-du-chat is a chromosomal deletion syndrome characterized by partial deletion of the short arm of chromosome 5. The clinical symptoms include growth and mental retardation, microcephaly, hypertelorism, epicanthal folds, hyptonia, and a high-pitched monochromatic cry that is usually considered diagnostic for the syndrome. Recently, a correlation between clinical features and the extent of the chromosome 5 deletions has identified two regions of the short arm that appear to be critical for the abnormal development manifested in this syndrome. Loss of a small region in 5p15.2 correlates with all of the clinical features of cri-du-chat with the exception of the cat-like cry, which maps to 5p15.3. Here the authors report the construction of a YAC contig that spans the chromosomal region in 5p15.2 that plays a major role in the etiology of the cri-du-chat syndrome. YACs that span the 2-Mb cri-du-chat critical region have been identified and characterized. This YAC contig lays the groundwork for the construction of a transcriptional map of this region and the eventual identification of genes involved in the clinical features associated with the cri-du-chat syndrome. It also provides a new diagnostic tool for cri-du-chat in the shape of a YAC clone that may span the entire critical region. 24 refs., 4 figs., 2 tabs.

  6. Using a book chat to improve attitudes and perceptions of long-term care staff about dementia.

    PubMed

    Larocque, Natasha; Schotsman, Chloe; Kaasalainen, Sharon; Crawshaw, Diane; McAiney, Carrie; Brazil, Emma

    2014-05-01

    This study sought to evaluate a book chat intervention based on Lisa Genova's novel, Still Alice, to influence long-term care (LTC) staff perceptions and attitudes when caring for individuals with dementia. A qualitative descriptive design was used. Eleven participants partook in a 2.5-hour book chat at a southern Ontario LTC facility. Following the book chat, participants answered two open-ended questions to assess how the book chat influenced their views on dementia. Thematic content analysis was used to analyze the qualitative questionnaire. Content analysis of the participants' responses revealed that the book chat positively influenced their attitudes and perceptions toward dementia, particularly by providing more insight into the individual's personal struggle with the disease. Furthermore, participants found that the book chat influenced their care practices. By creating innovative learning opportunities, attitudes and perceptions about dementia care can be transcended and greatly benefit staff, family, and residents. PMID:24443888

  7. Glucomannan synthesis in pea epicotyls: the mannose and glucose transferases.

    PubMed

    Piro, G; Zuppa, A; Dalessandro, G; Northcote, D H

    1993-01-01

    Membrane fractions and digitonin-solubilized enzymes prepared from stem segments isolated from the third internode of etiolated pea seedlings (Pisum sativum L. cv. Alaska) catalyzed the synthesis of a beta-1,4-[14C]mannan from GDP-D-[U-14C]-mannose, a mixed beta-1,3- and beta-1,4-[14C]glucan from GDP-D-[U-14C]-glucose and a beta-1,4-[14C]-glucomannan from both GDP-D-[U-14C]mannose and GDP-D-[U-14C]glucose. The kinetics of the membrane-bound and soluble mannan and glucan synthases were determined. The effects of ions, chelators, inhibitors of lipid-linked saccharides, polyamines, polyols, nucleotides, nucleoside-diphosphate sugars, acetyl-CoA, group-specific chemical probes, phospholipases and detergents on the membrane-bound mannan and glucan synthases were investigated. The beta-glucan synthase had different properties from other preparations which bring about the synthesis of beta-1,3-glucans (callose) and mixed beta-1,3- and beta-1,4- glucans and which use UDP-D-glucose as substrate. It also differed from xyloglucan synthase because in the presence of several concentrations of UDP-D-xylose in addition to GDP-D-glucose no xyloglucan was formed. Using either the membrane-bound or the soluble mannan synthase, GDP-D-glucose acted competitively in the presence of GDP-D-mannose to inhibit the incorporation of mannose into the polymer. This was not due to an inhibition of the transferase activity but was a result of the incorporation of glucose residues from GDP-D-glucose into a glucomannan. The kinetics and the composition of the synthesized glucomannan depended on the ratio of the concentrations of GDP-D-glucose and GDP-D-mannose that were available. Our data indicated that a single enzyme has an active centre that can use both GDP-D-mannose and GDP-D-glucose to bring about the synthesis of the heteropolysaccharide. PMID:7685647

  8. Acetylation phenotypes in patients with bladder carcinoma.

    PubMed

    Bicho, M P; Breitenfeld, L; Carvalho, A A; Manso, C F

    1988-01-01

    The present study was done to evaluate the possible association of bladder carcinoma with the slow acetylator phenotype in a portuguese population. 49 patients with bladder carcinoma were compared to a normal control group of 84 individuals. No statistically significant association was detected. But when subdividing the group of slow acetylators it is found that in the subgroup with 12-36% acetylation there is a higher percentage of patients, which is statistically significant. These results are in agreement with two other studies, using populations of similar ethnic origin. PMID:3265609

  9. KLF4 mediates the link between TGF-β1-induced gene transcription and H3 acetylation in vascular smooth muscle cells.

    PubMed

    He, Ming; Zheng, Bin; Zhang, Yu; Zhang, Xin-Hua; Wang, Chang; Yang, Zhan; Sun, Yan; Wu, Xiao-Li; Wen, Jin-Kun

    2015-09-01

    Transcriptional activation by transcription factors is coupled with histone acetylation and chromatin remodeling. However, the relationship between TGF-β1-induced gene transcription by Krüppel-like factor (KLF)-4 and histone acetylation remains unknown. In our study, KLF4 overexpression or knockdown, respectively increased or decreased H3 acetylation and p300 occupancy, which is concentrated in the region containing TGF-β1 control elements (TCEs) of the genes by TGF-β1 regulation during vascular smooth muscle cell (VSMC) differentiation. Coimmunoprecipitation and glutathione S-transferase pull-down assays showed that phosphatase and tensin homolog (PTEN) formed a complex with KLF4 to inhibit the phosphorylation of the latter in basal conditions. After TGF-β1 signaling activation, PTEN was phosphorylated by p38 MAPK or PI3K/Akt signaling, phosphorylated PTEN lost its ability to dephosphorylate KLF4, and the cofactors interacting with KLF4 switched from PTEN to p300. Then, KLF4-p300 complexes were recruited to KLF4-binding sites of the gene promoter of VSMCs, to acetylate histone H3 and activate transcription. In addition, phosphorylated KLF4 enhanced p300 histone acetyltransferase (HAT) activity via the p38 MAPK pathway, which may be responsible for H3 acetylation. Taken together, the results of our study reveal a novel mechanism whereby KLF4 mediates the link between TGF-β1-induced gene transcription activation and H3 acetylation during VSMC differentiation. PMID:26082460

  10. Nomenclature for mammalian soluble glutathione transferases.

    PubMed

    Mannervik, Bengt; Board, Philip G; Hayes, John D; Listowsky, Irving; Pearson, William R

    2005-01-01

    The nomenclature for human soluble glutathione transferases (GSTs) is extended to include new members of the GST superfamily that have been discovered, sequenced, and shown to be expressed. The GST nomenclature is based on primary structure similarities and the division of GSTs into classes of more closely related sequences. The classes are designated by the names of the Greek letters: Alpha, Mu, Pi, etc., abbreviated in Roman capitals: A, M, P, and so on. (The Greek characters should not be used.) Class members are distinguished by Arabic numerals and the native dimeric protein structures are named according to their subunit composition (e.g., GST A1-2 is the enzyme composed of subunits 1 and 2 in the Alpha class). Soluble GSTs from other mammalian species can be classified in the same manner as the human enzymes, and this chapter presents the application of the nomenclature to the rat and mouse GSTs. PMID:16399376

  11. Impact of acetylation on tumor metabolism

    PubMed Central

    Zhao, Di; Li, Fu-Long; Cheng, Zhou-Li; Lei, Qun-Ying

    2014-01-01

    Acetylation of protein lysine residues is a reversible and dynamic process that is controlled by histone acetyltransferases (HATs) and deacetylases (HDACs and SIRTs). Recent studies have revealed that acetylation modulates not only nuclear proteins but also cytoplasmic or mitochondrial proteins, including many metabolic enzymes. In tumors, cellular metabolism is reprogrammed to provide intermediates for biosynthesis such as nucleotides, fatty acids, and amino acids, and thereby favor the rapid proliferation of cancer cells and tumor development. An increasing number of investigations have indicated that acetylation plays an important role in tumor metabolism. Here, we summarize the substrates that are modified by acetylation, especially oncogenes, tumor suppressor genes, and enzymes that are implicated in tumor metabolism. PMID:27308346

  12. Acetylator phenotypes in Papua New Guinea

    PubMed Central

    Penketh, R J A; Gibney, S F A; Nurse, G T; Hopkinson, D A

    1983-01-01

    Acetylator phenotypes have been determined in 139 unrelated subjects from the hitherto untested populations of Papua New Guinea, and their relevance to current antituberculous isoniazid chemotherapy is discussed. PMID:6842533

  13. Acetyl-L-carnitine increases mitochondrial protein acetylation in the aged rat heart.

    PubMed

    Kerner, Janos; Yohannes, Elizabeth; Lee, Kwangwon; Virmani, Ashraf; Koverech, Aleardo; Cavazza, Claudio; Chance, Mark R; Hoppel, Charles

    2015-01-01

    Previously we showed that in vivo treatment of elderly Fisher 344 rats with acetylcarnitine abolished the age-associated defect in respiratory chain complex III in interfibrillar mitochondria and improved the functional recovery of the ischemic/reperfused heart. Herein, we explored mitochondrial protein acetylation as a possible mechanism for acetylcarnitine's effect. In vivo treatment of elderly rats with acetylcarnitine restored cardiac acetylcarnitine content and increased mitochondrial protein lysine acetylation and increased the number of lysine-acetylated proteins in cardiac subsarcolemmal and interfibrillar mitochondria. Enzymes of the tricarboxylic acid cycle, mitochondrial β-oxidation, and ATP synthase of the respiratory chain showed the greatest acetylation. Acetylation of isocitrate dehydrogenase, long-chain acyl-CoA dehydrogenase, complex V, and aspartate aminotransferase was accompanied by decreased catalytic activity. Several proteins were found to be acetylated only after treatment with acetylcarnitine, suggesting that exogenous acetylcarnitine served as the acetyl-donor. Two-dimensional fluorescence difference gel electrophoresis analysis revealed that acetylcarnitine treatment also induced changes in mitochondrial protein amount; a two-fold or greater increase/decrease in abundance was observed for thirty one proteins. Collectively, our data provide evidence for the first time that in the aged rat heart in vivo administration of acetylcarnitine provides acetyl groups for protein acetylation and affects the amount of mitochondrial proteins. PMID:25660059

  14. Levels of histone acetylation in thyroid tumors.

    PubMed

    Puppin, Cinzia; Passon, Nadia; Lavarone, Elisa; Di Loreto, Carla; Frasca, Francesco; Vella, Veronica; Vigneri, Riccardo; Damante, Giuseppe

    2011-08-12

    Histone acetylation is a major mechanism to regulate gene transcription. This post-translational modification is modified in cancer cells. In various tumor types the levels of acetylation at several histone residues are associated to clinical aggressiveness. By using immunohistochemistry we show that acetylated levels of lysines at positions 9-14 of H3 histone (H3K9-K14ac) are significantly higher in follicular adenomas (FA), papillary thyroid carcinomas (PTC), follicular thyroid carcinomas (FTC) and undifferentiated carcinomas (UC) than in normal tissues (NT). Similar data have been obtained when acetylated levels of lysine 18 of H3 histone (H3K18ac) were evaluated. In this case, however, no difference was observed between NT and UC. When acetylated levels of lysine 12 of H4 histone (H4K12ac) were evaluated, only FA showed significantly higher levels in comparison with NT. These data indicate that modification histone acetylation is an early event along thyroid tumor progression and that H3K18 acetylation is switched off in the transition between differentiated and undifferentiated thyroid tumors. By using rat thyroid cell lines that are stably transfected with doxycyclin-inducible oncogenes, we show that the oncoproteins RET-PTC, RAS and BRAF increase levels of H3K9-K14ac and H3K18ac. In the non-tumorigenic rat thyroid cell line FRTL-5, TSH increases levels of H3K18ac. However, this hormone decreases levels of H3K9-K14ac and H4K12ac. In conclusion, our data indicate that neoplastic transformation and hormonal stimulation can modify levels of histone acetylation in thyroid cells. PMID:21763277

  15. Protein acetylation in metabolism - metabolites and cofactors.

    PubMed

    Menzies, Keir J; Zhang, Hongbo; Katsyuba, Elena; Auwerx, Johan

    2016-01-01

    Reversible acetylation was initially described as an epigenetic mechanism regulating DNA accessibility. Since then, this process has emerged as a controller of histone and nonhistone acetylation that integrates key physiological processes such as metabolism, circadian rhythm and cell cycle, along with gene regulation in various organisms. The widespread and reversible nature of acetylation also revitalized interest in the mechanisms that regulate lysine acetyltransferases (KATs) and deacetylases (KDACs) in health and disease. Changes in protein or histone acetylation are especially relevant for many common diseases including obesity, diabetes mellitus, neurodegenerative diseases and cancer, as well as for some rare diseases such as mitochondrial diseases and lipodystrophies. In this Review, we examine the role of reversible acetylation in metabolic control and how changes in levels of metabolites or cofactors, including nicotinamide adenine dinucleotide, nicotinamide, coenzyme A, acetyl coenzyme A, zinc and butyrate and/or β-hydroxybutyrate, directly alter KAT or KDAC activity to link energy status to adaptive cellular and organismal homeostasis. PMID:26503676

  16. Connecting developmental constructions to the internet: identity presentation and sexual exploration in online teen chat rooms.

    PubMed

    Subrahmanyam, Kaveri; Smahel, David; Greenfield, Patricia

    2006-05-01

    The authors examined the online construction of identity and sexuality in a large sample of conversations from monitored and unmonitored teen chat rooms. More than half of the 583 participants (identified by a distinct screen name) communicated identity information, most frequently gender. In this way, participants compensated for the text-based chat environment by providing information about themselves that would be visible and obvious in face-to-face communication. Sexual themes constituted 5% of all utterances (1 sexual comment per minute); bad or obscene language constituted 3% of the sample (1 obscenity every 2 minutes). Participants who self-identified as female produced more implicit sexual communication, participants who self-identified as male produced more explicit sexual communication. The protected environment of monitored chat (hosts who enforce basic behavioral rules) contained an environment with less explicit sexuality and fewer obscenities than the freer environment of unmonitored chat. These differences were attributable both to the monitoring process itself and to the differing populations attracted to each type of chat room (monitored: more participants self-identified as younger and female; unmonitored: more participants self-identified as older and male). PMID:16756432

  17. Single prenyl-binding site on protein prenyl transferases

    PubMed Central

    Desnoyers, Luc; Seabra, Miguel C.

    1998-01-01

    Three distinct protein prenyl transferases, one protein farnesyl transferase (FTase) and two protein geranylgeranyl transferases (GGTase), catalyze prenylation of many cellular proteins. One group of protein substrates contains a C-terminal CAAX motif (C is Cys, A is aliphatic, and X is a variety of amino acids) in which the single cysteine residue is modified with either farnesyl or geranylgeranyl (GG) by FTase or GGTase type-I (GGTase-I), respectively. Rab proteins constitute a second group of substrates that contain a C-terminal double-cysteine motif (such as XXCC in Rab1a) in which both cysteines are geranylgeranylated by Rab GG transferase (RabGGTase). Previous characterization of CAAX prenyl transferases showed that the enzymes form stable complexes with their prenyl pyrophosphate substrates, acting as prenyl carriers. We developed a prenyl-binding assay and show that RabGGTase has a prenyl carrier function similar to the CAAX prenyl transferases. Stable RabGGTase:GG pyrophosphate (GGPP), FTase:GGPP, and GGTase-I:GGPP complexes show 1:1 (enzyme:GGPP) stoichiometry. Chromatographic analysis of prenylated products after single turnover reactions by using isolated RabGGTase:GGPP complex revealed that Rab is mono-geranylgeranylated. This study establishes that all three protein prenyl transferases contain a single prenyl-binding site and suggests that RabGGTase transfers two GG groups to Rabs in independent and consecutive reactions. PMID:9770475

  18. The Q-CHAT (Quantitative CHecklist for Autism in Toddlers): A Normally Distributed Quantitative Measure of Autistic Traits at 18-24 Months of Age--Preliminary Report

    ERIC Educational Resources Information Center

    Allison, Carrie; Baron-Cohen, Simon; Wheelwright, Sally; Charman, Tony; Richler, Jennifer; Pasco, Greg; Brayne, Carol

    2008-01-01

    We report a major revision of the CHecklist for Autism in Toddlers (CHAT). This "quantitative" CHAT (Q-CHAT) contains 25 items, scored on a 5 point scale (0-4). The Q-CHAT was completed by parents of n = 779 unselected toddlers (mean age 21 months) and n = 160 toddlers and preschoolers (mean age 44 months) with an Autism Spectrum Condition (ASC).…

  19. [Dental education for college students based on WeChat public platform].

    PubMed

    Chen, Chuan-Jun; Sun, Tan

    2016-06-01

    The authors proposed a model for dental education based on WeChat public platform. In this model, teachers send various kinds of digital teaching information such as PPT,word and video to the WeChat public platform and students share the information for preview before class and differentiate the key-point knowledge from those information for in-depth learning in class. Teachers also send reference materials for expansive learning after class. Questionaire through the WeChat public platform is used to evaluate teaching effect of teachers and improvement may be taken based on the feedback questionnaire. A discussion and interaction based on WeCchat between students and teacher can be aroused on a specific topic to reach a proper solution. With technique development of mobile terminal, mobile class will come true in near future. PMID:27609397

  20. Autonomy in nursing students process of knowledge construction: the educational chat as a teaching tool.

    PubMed

    da Silva, Ana Paula Scheffer Schell; Pedro, Eva Néri Rubim

    2010-01-01

    This documental study has the qualitative approach of a case study. It analyzes how autonomy has been developed in nursing students process of knowledge construction, in a context mediated by the use of educational chat in Learning Management Systems (LMS). The analyzed materials were eight discussions promoted by students, professors, and monitors in the chat session of TelEduc LMS. The software NVivo was used to categorize data and Content Analysis for the analysis of information. Data analysis used Freire as a reference point, revealing that nursing students need to develop their autonomy by acknowledging their incompleteness. Professors can aid this process by problematizing and developing critical dialogical relations. The potential of the educational chat as a pedagogical tool is highlighted because it encourages students to autonomously seek knowledge. PMID:20549120

  1. Interactions between Text Chat and Audio Modalities for L2 Communication and Feedback in the Synthetic World "Second Life"

    ERIC Educational Resources Information Center

    Wigham, Ciara R.; Chanier, Thierry

    2015-01-01

    This paper reports on a study of the interactions between text chat and audio modalities in L2 communication in a synthetic (virtual) world and observes whether the text chat modality was used for corrective feedback and the characteristics of the latter. This is examined within the context of a hybrid content and language integrated learning…

  2. Observations of Chat Room Conversations on the Internet: Implications for Educators Addressing the Needs of Female Adolescents

    ERIC Educational Resources Information Center

    Sanger, Dixie; Ritzman, Mitzi; LaCost, Barbara; Stofer, Keri; Long, Amie; Grady, Marilyn

    2005-01-01

    This qualitative study explored the meanings of chat room conversations through observations of teenagers using the Internet. Adolescent girls were a focus because of their shaky sense of self. Participants in ten chat rooms included 534 individuals. Six themes, emerging from analyzing 2526 utterances [descriptive statements], included (a)…

  3. 77 FR 49059 - Requested Administrative Waiver of the Coastwise Trade Laws: Vessel CHAT DE MER; Invitation for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... published on April 11, 2000 (65 FR 19477-78). By Order of the Maritime Administrator. Dated: August 9, 2012... Maritime Administration Requested Administrative Waiver of the Coastwise Trade Laws: Vessel CHAT DE MER... of the vessel CHAT DE MER is: Intended Commercial Use of Vessel: Primarily carrying passengers...

  4. Bringing Japan and Taiwan Closer Electronically: A Look at an Intercultural Online Synchronic Chat Task and Its Effect on Motivation

    ERIC Educational Resources Information Center

    Freiermuth, Mark R.; Huang, Hsin-chou

    2012-01-01

    This study examines the motivation of 20 Japanese students of English as a foreign language (EFL) who chatted electronically with 19 Taiwanese EFL students using online synchronous chat software. In particular, we were interested in four factors that affect task-based motivation: the willingness to communicate, task attractiveness, task…

  5. Effects of Face-to-Face versus Chat Communication on Performance in a Collaborative Inquiry Modeling Task

    ERIC Educational Resources Information Center

    Sins, Patrick H. M.; Savelsbergh, Elwin R.; van Joolingen, Wouter R.; van Hout-Wolters, Bernadette H. A. M.

    2011-01-01

    In many contemporary collaborative inquiry learning environments, chat is being used as a means for communication. Still, it remains an open issue whether chat communication is an appropriate means to support the deep reasoning process students need to perform in such environments. Purpose of the present study was to compare the impact of chat…

  6. When Is It Appropriate to Talk? Managing Overlapping Talk in Multi-Participant Voice-Based Chat Rooms

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph

    2009-01-01

    There has been extensive reporting on the interactional characteristics of multi-participant text-based chat rooms. In these chat rooms there are several students typing at the same time, often on more than one topic. As a result, it is not uncommon to see multiple overlapping utterances. Despite these communicative challenges, research suggests…

  7. Chat (Catha edulis): a socio economic crop in Harar Region, Eastern Ethiopia.

    PubMed

    Kandari, Laxman S; Yadav, Hiranmai R; Thakur, Ashok K; Kandari, Tripti

    2014-01-01

    Chat (Catha edulis) is an important perennial crop and its leaves are chewed for a stimulating effect. It is widely cultivated in the Ethiopian highlands of Oromia region and is figured as Ethiopia's second largest foreign exchange earner. Its cultivation accounts for about 70% of farmer's income in the study area. The common effect of its consumption leads to insomnia, a condition that the users sometimes try to overcome with sedatives or alcohol. The present study is an attempt to survey and assess the impact of crop on the community. It has been observed to implicate health problems, reduces savings and nutritional standards of the family members. The chat yields in the area ranges from 1500-1800 kg/ha through monoculture. During the study, the average monthly income of the family practicing chat cultivation was from Birr 8, 533.00 to 13, 166.00 kg/ha per year in Baate and Genede cultivating areas. When the average cost per/ha was rupees 60/kg. The present study shows that during the recent past, leaf consumption has increased significantly. Chat growers are not only producers but also traders and consumers. Its consumption has become a widespread habit from secondary schools. Highest number of consumers was found to be among drivers followed by students and shopkeepers. The consumption of the plant is not considered a taboo but on contrary a status symbol in the region. It has no legal or moral implications and is considered as a part of custom and habit of local people. High value cash crop like vegetables and orchard fruits needs to be used as a replacement for chat which could be a regular source of income to farmers. Alternative sources of income for farmers needs to be scientifically worked out and proposed keeping in view the proportion of agricultural land reserved under chat cultivation and to increase the production of food grains being produced. PMID:25332879

  8. The Genetic Architecture of Murine Glutathione Transferases

    PubMed Central

    Lu, Lu; Pandey, Ashutosh K.; Houseal, M. Trevor; Mulligan, Megan K.

    2016-01-01

    Glutathione S-transferase (GST) genes play a protective role against oxidative stress and may influence disease risk and drug pharmacokinetics. In this study, massive multiscalar trait profiling across a large population of mice derived from a cross between C57BL/6J (B6) and DBA2/J (D2)—the BXD family—was combined with linkage and bioinformatic analyses to characterize mechanisms controlling GST expression and to identify downstream consequences of this variation. Similar to humans, mice show a wide range in expression of GST family members. Variation in the expression of Gsta4, Gstt2, Gstz1, Gsto1, and Mgst3 is modulated by local expression QTLs (eQTLs) in several tissues. Higher expression of Gsto1 in brain and liver of BXD strains is strongly associated (P < 0.01) with inheritance of the B6 parental allele whereas higher expression of Gsta4 and Mgst3 in brain and liver, and Gstt2 and Gstz1 in brain is strongly associated with inheritance of the D2 parental allele. Allele-specific assays confirmed that expression of Gsto1, Gsta4, and Mgst3 are modulated by sequence variants within or near each gene locus. We exploited this endogenous variation to identify coexpression networks and downstream targets in mouse and human. Through a combined systems genetics approach, we provide new insight into the biological role of naturally occurring variants in GST genes. PMID:26829228

  9. Kinetics and catalytic properties of coenzyme A transferase from Peptostreptococcus elsdenii.

    PubMed Central

    Schulman, M; Valentino, D

    1976-01-01

    Coenzyme A (CoA) transferase from Peptostreptococcus elsdenii was purified to homogeneity, and some of its physical and catalytic properties were determined. The native enzyme has a molecular weight of 181,000 and is composed of two alpha subunits (molecular weight, 65,000) and one beta subunit (molecular weight 50,000). Heat treatment of the crude cell extract to 58 degrees C causes proteolysis of the native enzyme and yields a catalytically active enzyme with an approximate molecular weight of 120,000. The native CoA transferase is specific for CoA esters of short-chain alkyl monocarboxylic acids. With acetate as CoA acceptor the enzyme is active with propionyl-, butyryl-, isobutyryl-, valeryl-, isovaleryl,- and hexanoyl-CoA but not with heptanoyl or longer-chain CoA esters. There is no activity with acetoacetyl-CoA or the CoA esters of dicarboxylic acids. Steady-state kinetics indicated that the reaction proceeds via a classical bi-, bi-ping-pong mechanism. Maximal activity is obtained with propionyl- or butyryl-CoA, and both the Vmax and Km decrease as the alkyl chain length of the CoA ester increases. All CoA esters apompetitive inhibitor although it is not active as a substrate. Evidence for an enzyme CoA intermediate was provided by demonstration of an exchange between 14C-free acids (acetate and butyrate) and their corresponding CoA esters and by isolation of a 3H-labeled CoA enzyme after incubation of the enzyme with 3H-labeled acetyl-CoA. Approximately 2 mol of CoA was bound per mol of enzyme. Images PMID:977540

  10. Histone Acetylation Regulates Intracellular pH

    PubMed Central

    McBrian, Matthew A.; Behbahan, Iman Saramipoor; Ferrari, Roberto; Su, Trent; Huang, Ta-Wei; Li, Kunwu; Hong, Candice S.; Christofk, Heather R.; Vogelauer, Maria; Seligson, David B.; Kurdistani, Siavash K.

    2014-01-01

    SUMMARY Differences in global levels of histone acetylation occur in normal and cancer cells, although the reason why cells regulate these levels has been unclear. Here we demonstrate a role for histone acetylation in regulating intracellular pH (pHi). As pHi decreases, histones are globally deacetylated by histone deacetylases (HDACs), and the released acetate anions are coexported with protons out of the cell by monocarboxylate transporters (MCTs), preventing further reductions in pHi. Conversely, global histone acetylation increases as pHi rises, such as when resting cells are induced to proliferate. Inhibition of HDACs or MCTs decreases acetate export and lowers pHi, particularly compromising pHi maintenance in acidic environments. Global deacetylation at low pH is reflected at a genomic level by decreased abundance and extensive redistribution of acetylation throughout the genome. Thus, acetylation of chromatin functions as a rheostat to regulate pHi with important implications for mechanism of action and therapeutic use of HDAC inhibitors. PMID:23201122

  11. Proteomic analysis of acetylation in thermophilic Geobacillus kaustophilus.

    PubMed

    Lee, Dong-Woo; Kim, Dooil; Lee, Yong-Jik; Kim, Jung-Ae; Choi, Ji Young; Kang, Sunghyun; Pan, Jae-Gu

    2013-08-01

    Recent analysis of prokaryotic N(ε)-lysine-acetylated proteins highlights the posttranslational regulation of a broad spectrum of cellular proteins. However, the exact role of acetylation remains unclear due to a lack of acetylated proteome data in prokaryotes. Here, we present the N(ε)-lysine-acetylated proteome of gram-positive thermophilic Geobacillus kaustophilus. Affinity enrichment using acetyl-lysine-specific antibodies followed by LC-MS/MS analysis revealed 253 acetylated peptides representing 114 proteins. These acetylated proteins include not only common orthologs from mesophilic Bacillus counterparts, but also unique G. kaustophilus proteins, indicating that lysine acetylation is pronounced in thermophilic bacteria. These data complement current knowledge of the bacterial acetylproteome and provide an expanded platform for better understanding of the function of acetylation in cellular metabolism. PMID:23696451

  12. Detection of glutathione transferase activity on polyacrylamide gels.

    PubMed

    Ricci, G; Lo Bello, M; Caccuri, A M; Galiazzo, F; Federici, G

    1984-12-01

    A simple and sensitive assay for glutathione transferase activity on polyacrylamide gel is described. The method is based on the fast reduction of nitroblue tetrazolium salt by glutathione. Blue insoluble formazan colors the gel except in the glutathione transferase area. The stable and defined colorless zone is still detectable with 0.005 unit enzyme. This technique has been successfully applied with enzyme preparations of human heart and other tissues. PMID:6532239

  13. The substrate promiscuity of a phosphopantetheinyl transferase SchPPT for coenzyme A derivatives and acyl carrier proteins.

    PubMed

    Wang, Yue-Yue; Luo, Hong-Dou; Zhang, Xiao-Sheng; Lin, Tao; Jiang, Hui; Li, Yong-Quan

    2016-03-01

    Phosphopantetheinyl transferases (PPTases) catalyze the posttranslational modification of acyl carrier proteins (ACPs) in fatty acid synthases (FASs), ACPs in polyketide synthases, and peptidyl carrier proteins (PCPs) in nonribosomal peptide synthetases (NRPSs) in all organisms. Some bacterial PPTases have broad substrate specificities for ACPs/PCPs and/or coenzyme A (CoA)/CoA analogs, facilitating their application in metabolite production in hosts and/or labeling of ACPs/PCPs, respectively. Here, a group II PPTase SchPPT from Streptomyces chattanoogensis L10 was characterized to accept a heterologous ACP and acetyl-CoA. Thus, SchPPT is a promiscuous PPTase and may be used on polyketide production in heterologous bacterial host and labeling of ACPs. PMID:26748983

  14. Modification of RelA by O-linked N-acetylglucosamine links glucose metabolism to NF-κB acetylation and transcription

    PubMed Central

    Allison, David F.; Wamsley, J. Jacob; Kumar, Manish; Li, Duo; Gray, Lisa G.; Hart, Gerald W.; Jones, David R.; Mayo, Marty W.

    2012-01-01

    The molecular mechanisms linking glucose metabolism with active transcription remain undercharacterized in mammalian cells. Using nuclear factor-κB (NF-κB) as a glucose-responsive transcription factor, we show that cells use the hexosamine biosynthesis pathway and O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) to potentiate gene expression in response to tumor necrosis factor (TNF) or etoposide. Chromatin immunoprecipitation assays demonstrate that, upon induction, OGT localizes to NF-κB–regulated promoters to enhance RelA acetylation. Knockdown of OGT abolishes p300-mediated acetylation of RelA on K310, a posttranslational mark required for full NF-κB transcription. Mapping studies reveal T305 as an important residue required for attachment of the O-GlcNAc moiety on RelA. Furthermore, p300 fails to acetylate a full-length RelA(T305A) mutant, linking O-GlcNAc and acetylation events on NF-κB. Reconstitution of RelA null cells with the RelA(T305A) mutant illustrates the importance of this residue for NF-κB–dependent gene expression and cell survival. Our work provides evidence for a unique regulation where attachment of the O-GlcNAc moiety to RelA potentiates p300 acetylation and NF-κB transcription. PMID:23027940

  15. Acetylation of bleached Kraft pulp: effect of xylan content on properties of acetylated compounds.

    PubMed

    Peredo, Karol; Reyes, Herna; Escobar, Danilo; Vega-Lara, Johana; Berg, Alex; Pereira, Miguel

    2015-03-01

    Bleached Kraft pulp (BKP) from Eucalyptus globulus and cotton xylan blends (CXB) was acetylated. The effects of xylan content on cellulose acetylation and the properties of the acetylated material were studied. An increase in xylan content caused a slight decrease in the degree of substitution (2.98 to 2.68 for CXB; 2.93 to 2.84 for BKP). Thermal analysis showed that the melting temperature also decreases from 268.0 to 188.8 °C for CXB and from 221.4 to 212.8 °C for BKP. Moreover, the solubility decreased due to the partial dissolution of acetylated xylans. The presence of xylans during Kraft pulp acetylation does not have a significant negative effect on the physical properties of the acetylated material, but the decrease in melting temperature was beneficial for the application of acetylated polymer as a natural internal plasticizer. This is considered to be an important argument for BKP utilization in the cellulose acetate manufacturing process. PMID:25498729

  16. UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases: Completion of the family tree

    PubMed Central

    Raman, Jayalakshmi; Guan, Yu; Perrine, Cynthia L; Gerken, Thomas A; Tabak, Lawrence A

    2012-01-01

    The formation of mucin-type O-glycans is initiated by an evolutionarily conserved family of enzymes, the UDP-N-acetyl-α-d-galactosamine:polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts). The human genome encodes 20 transferases; 17 of which have been characterized functionally. The complexity of the GalNAc-T family reflects the differential patterns of expression among the individual enzyme isoforms and the unique substrate specificities which are required to form the dense arrays of glycans that are essential for mucin function. We report the expression patterns and enzymatic activity of the remaining three members of the family and the further characterization of a recently reported isoform, GalNAc-T17. One isoform, GalNAcT-16 that is most homologous to GalNAc-T14, is widely expressed (abundantly in the heart) and has robust polypeptide transferase activity. The second isoform GalNAc-T18, most similar to GalNAc-T8, -T9 and -T19, completes a discrete subfamily of GalNAc-Ts. It is widely expressed and has low, albeit detectable, activity. The final isoform, GalNAc-T20, is most homologous to GalNAc-T11 but lacks a lectin domain and has no detectable transferase activity with the panel of substrates tested. We have also identified and characterized enzymatically active splice variants of GalNAc-T13 that differ in the sequence of their lectin domain. The variants differ in their affinities for glycopeptide substrates. Our findings provide a comprehensive view of the complexities of mucin-type O-glycan formation and provide insight into the underlying mechanisms employed to heavily decorate mucins and mucin-like domains with carbohydrate. PMID:22186971

  17. Non-enzymatic protein acetylation detected by NAPPA protein arrays*

    PubMed Central

    Olia, Adam S.; Barker, Kristi; McCullough, Cheryl E.; Tang, Hsin-Yao; Speicher, David W.; Qiu, Ji; LaBaer, Joshua; Marmorstein, Ronen

    2015-01-01

    Acetylation is a post-translational modification that occurs on thousands of proteins located in many cellular organelles. This process mediates many protein functions and modulates diverse biological processes. In mammalian cells, where acetyl-CoA is the primary acetyl donor, acetylation in the mitochondria is thought to occur by chemical means due to the relatively high concentration of acetyl-CoA located in this organelle. In contrast, acetylation outside of the mitochondria is thought to be mediated predominantly by acetyltransferase enzymes. Here we address the possibility that non-enzymatic chemical acetylation outside of the mitochondria may be more common than previously appreciated. We employed the Nucleic Acid Programmable Protein Array platform to perform an unbiased screen for human proteins that undergo chemical acetylation, which resulted in the identification of a multitude of proteins with diverse functions and cellular localization. Mass spectrometry analysis revealed that basic residues typically precede the acetylated lysine in the −7 to −3 position, and we show by mutagenesis that these basic residues contribute to chemical acetylation capacity. We propose that these basic residues lower the pKa of the substrate lysine for efficient chemical acetylation. Many of the identified proteins reside outside of the mitochondria, and have been previously demonstrated to be acetylated in vivo. As such, our studies demonstrate that chemical acetylation occurs more broadly throughout the eukaryotic cell than previously appreciated, and suggests that this post-translational protein modification may have more diverse roles in protein function and pathway regulation. PMID:26083674

  18. Nucleosome structure incorporated histone acetylation site prediction in arabidopsis thaliana

    PubMed Central

    2010-01-01

    Abstract Background Acetylation is a crucial post-translational modification for histones, and plays a key role in gene expression regulation. Due to limited data and lack of a clear acetylation consensus sequence, a few researches have focused on prediction of lysine acetylation sites. Several systematic prediction studies have been conducted for human and yeast, but less for Arabidopsis thaliana. Results Concerning the insufficient observation on acetylation site, we analyzed contributions of the peptide-alignment-based distance definition and 3D structure factors in acetylation prediction. We found that traditional structure contributes little to acetylation site prediction. Identified acetylation sites of histones in Arabidopsis thaliana are conserved and cross predictable with that of human by peptide based methods. However, the predicted specificity is overestimated, because of the existence of non-observed acetylable site. Here, by performing a complete exploration on the factors that affect the acetylability of lysines in histones, we focused on the relative position of lysine at nucleosome level, and defined a new structure feature to promote the performance in predicting the acetylability of all the histone lysines in A. thaliana. Conclusion We found a new spacial correlated acetylation factor, and defined a ε-N spacial location based feature, which contains five core spacial ellipsoid wired areas. By incorporating the new feature, the performance of predicting the acetylability of all the histone lysines in A. Thaliana was promoted, in which the previous mispredicted acetylable lysines were corrected by comparing to the peptide-based prediction. PMID:21047388

  19. Doing Being Reprehensive: Some Interactional Features of English as a Lingua Franca in a Chat Room

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph

    2012-01-01

    Great diversity exists in the way English is being used in the world today. It is now not uncommon to hear a Korean and a Brazilian do business in English, or a Syrian and a Norwegian debating politics in an English-speaking chat room. As opportunities to use English increase and evolve, researchers are left with the difficult challenge of…

  20. Comparing Six Video Chat Tools: A Critical Evaluation by Language Teachers

    ERIC Educational Resources Information Center

    Eroz-Tuga, Betil; Sadler, Randall

    2009-01-01

    This article presents a critical comparison of the usefulness and practicality of six CMC video chat tools (CUworld, ICQ, MSN Messenger, Paltalk, Skype, and Yahoo Messenger) from the perspective of language teaching professionals. This comparison is based on the results of a semester-long project between graduate students at an American university…

  1. Redesigning Chat Forum for Critical Thinking in a Problem-Based Learning Environment

    ERIC Educational Resources Information Center

    Chiang, Akcell Chii-Chung; Fung, Isaac Pak-Wah

    2004-01-01

    Support is needed to promote problem-based learning (PBL) and to enhance critical thinking skills in discussion-based Internet forums. By advancing the capabilities of chat room and forum software, problem-based discussions for learning can be supported further in online learning environments. In this paper, the authors report on MALESAbrain, an…

  2. Negotiation of Meaning and Noticing in Text-Based Online Chat

    ERIC Educational Resources Information Center

    Shekary, M.; Tahririan, M. H.

    2006-01-01

    The aim of this study was to explore the claim that the hybrid nature of synchronic computer-mediated chat (SCMC) promotes the noticing of target language forms, which may, in turn, stimulate the process of second language actuation. When viewed in the context of interaction theory, the hybrid nature of SCMC makes online negotiation a potentially…

  3. Cognitive, Social and Teaching Presence in a Virtual World and a Text Chat

    ERIC Educational Resources Information Center

    Traphagan, Tomoko Watanabe; Chiang, Yueh-hui Vanessa; Chang, Hyeseung Maria; Wattanawaha, Benjaporn; Lee, Haekyung; Mayrath, Michael Charles; Woo, Jeongwon; Yoon, Hyo-Jin; Jee, Min Jung; Resta, Paul E.

    2010-01-01

    Using a framework of cognitive, social, and teaching presence, the nature of learning experiences in a three-dimensional virtual world environment (Second Life) and a text-chat learning environment without visuals (TeachNet) were investigated. A mixed method of code frequencies, coherence graphs, interviews, and a survey was used. The results…

  4. Screening for Autism in Iranian Preschoolers: Contrasting M-CHAT and a Scale Developed in Iran

    ERIC Educational Resources Information Center

    Samadi, Sayyed Ali; McConkey, Roy

    2015-01-01

    Suitable screening instruments for the early diagnosis of autism are not readily available for use with preschoolers in non-Western countries. This study evaluated two tools: M-CHAT which is widely used internationally and one developed in Iran called Hiva. A population sample was recruited of nearly 3000 preschoolers in one Iranian city. Parents…

  5. Inflectional Morphology in Cri du Chat Syndrome--A Case Study

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2012-01-01

    This study examined morphological skills in a girl with cri du chat syndrome, addressing three questions: (1) To what extent does the subject inflect words? (2) To what extent are words inflected correctly? (3) To what extent do the inflected words reflect productive morphological rules, and to what extent can they be considered to be…

  6. Polymorphisms of CHAT but not TFAM or VR22 are Associated with Alzheimer Disease Risk.

    PubMed

    Gao, Lili; Zhang, Yan; Deng, Jinghua; Yu, Wenbing; Yu, Yunxia

    2016-01-01

    BACKGROUND Alzheimer disease (AD) is a chronic neurodegenerative disease that is one of the most prevalent health problems among seniors. The cause of AD has not yet been elucidated, but many risk factors have been identified that might contribute to the pathogenesis and prognosis of AD. We conducted a meta-analysis of studies involving CHAT, TFAM, and VR22 polymorphisms and AD susceptibility to further understand the pathogenesis of AD. MATERIAL AND METHODS PubMed/Medline, Embase, Web of Science, the Cochrane Library, and Google Scholar were searched for relevant articles. Rs1880676, rs2177369, rs3810950, and rs868750 of CHAT; rs1937 and rs2306604 of TFAM; and rs10997691 and rs7070570 of VR22 are studied in this meta-analysis. RESULTS A total of 51 case-control studies with 16 446 cases and 16 057 controls were enrolled. For CHAT, rs2177369 (G>A) in whites and rs3810950 (G>A) in Asians were found to be associated with AD susceptibility. No association was detected between rs1880676 and rs868750 and AD risk. For TFAM and VR22, no significant association was detected in studied single-nucleotide polymorphisms (SNPs). CONCLUSIONS Rs2177369 and rs3810950 of CHAT are associated with AD susceptibility, but rs1880676 and rs868750 are not. Rs1937 and rs2306604 of TFAM, and rs10997691 and rs7070570 of VR22 are not significantly associated with AD risk. PMID:27272392

  7. Researching Contradictions: Cultural Historical Activity Theory Research (CHAT) in the English Classroom

    ERIC Educational Resources Information Center

    Thompson, Ian

    2015-01-01

    This article argues that Cultural Historical Activity Theory (CHAT) is an appropriate theoretical and methodological framework for researchers in English interested in the social contexts of culture and its relationship with the formation of mind and activity in the English classroom. Two key concepts in Vygotsky's thought central to understanding…

  8. Speech and Language Development in Cri Du Chat Syndrome: A Critical Review

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2008-01-01

    This article reviews research on speech and language abilities in people with cri du chat syndrome (CCS). CCS is a rare genetic disorder, with an estimated incidence between 1 in 15,000 and 1 in 50,000 births, resulting from a deletion on the short arm of chromosome 5. In general, individuals have delayed speech and language development, and some…

  9. Grammatical Constructions in Cri du Chat Syndrome--Findings from a Case Study

    ERIC Educational Resources Information Center

    Kristoffersen, Kristian Emil

    2009-01-01

    The literature on grammatical skills in persons with Cri du chat syndrome (CCS) is very limited, and the need for more knowledge in this area is thus evident, in particular for speech and language therapists working with individuals with this syndrome. This case study report describes the syntactic skills of a 14-year-old Norwegian girl with CCS.…

  10. Effects of Interactive Chat versus Independent Writing on L2 Learning

    ERIC Educational Resources Information Center

    Tare, Medha; Golonka, Ewa M.; Vatz, Karen; Bonilla, Carrie L.; Crooks, Carolyn; Strong, Rachel

    2014-01-01

    This study examines the importance of interaction for second language (L2) acquisition by analyzing outcomes from two types of out-of-class activities. The study compared: (a) interactive homework, completed via text chat, and (b) individual homework, completed via independent writing. In a between-subjects design, participants in two…

  11. Combining IM and Vendor-Based Chat: A Report from the Frontlines of an Integrated Service

    ERIC Educational Resources Information Center

    Ward, David; Kern, M. Kathleen

    2006-01-01

    Driven by studies showing that Millennials (ages 18-24) have adopted IM (instant messaging) as a standard communications medium, many libraries are reaching out to their own patrons in this way. At the same time, some of these libraries have invested thousands of dollars in vendor-based chat reference solutions that provide duplicate…

  12. Chatting in L2 Spanish: Interactivity, Self-Efficacy and Interpersonal Relations

    ERIC Educational Resources Information Center

    Sanchez-Castro, Olga; Mrowa-Hopkins, Colette

    2012-01-01

    This study seeks to examine variations in patterns of interactivity as they are displayed in the ongoing discourse construction of high and low self-efficacy learners of Spanish in the context of computer-mediated-communication. The paper specifically focuses on the analysis of synchronous text chats of six university students of Spanish at…

  13. A Technology User's Bill of Rights: Lessons Learned in Chat Rooms

    ERIC Educational Resources Information Center

    Norton-Meier, Lori A.

    2004-01-01

    For the past five years, the author has spent time talking with, interviewing, interacting with, and investigating language with adolescent females in chat rooms while they engage in synchronous talk. The discussion often centers on their interest in pop culture--music, movies, television, books, games, and anything else that is worthy of…

  14. Sleep in Individuals with Cri du Chat Syndrome: A Comparative Study

    ERIC Educational Resources Information Center

    Maas, A. P. H. M.; Didden, R.; Korzilius, H.; Braam, W.; Smits, M. G.; Curfs, L. M. G.

    2009-01-01

    Background: Sleep problems are common in individuals with intellectual disability. Little is known about sleep in children and adults with Cri du Chat syndrome (CDC). Method: Sleep was investigated in 30 individuals with CDC using a sleep questionnaire. Sleep problems and sleep behaviours in individuals with CDC were compared with individuals with…

  15. Changes in Reference Question Complexity Following the Implementation of a Proactive Chat System: Implications for Practice

    ERIC Educational Resources Information Center

    Maloney, Krisellen; Kemp, Jan H.

    2015-01-01

    There has been longstanding debate about whether the level of complexity of questions received at reference desks and via online chat services requires a librarian's expertise. Continued decreases in the number and complexity of reference questions have all but ended the debate; many academic libraries no longer staff service points with…

  16. What Are Youth Asking about Drugs? A Report of NIDA Drug Facts Chat Day

    ERIC Educational Resources Information Center

    Morton, Cory M.; Hoefinger, Heidi; Linn-Walton, Rebecca; Aikins, Ross; Falkin, Gregory P.

    2015-01-01

    The current study analyzes a sample of questions about drugs asked online by youth who participated in the National Institute on Drug Abuse's (NIDA) "Drug Facts Chat Day." The types of drugs youth asked about were coded into 17 substance categories, and the topics they raised were coded into seven thematic categories. The top five…

  17. Comparing Protest Movements in Chile and California: Interculturality in an Internet Chat Exchange

    ERIC Educational Resources Information Center

    Menard-Warwick, Julia

    2009-01-01

    This paper is based on an analysis of chat transcripts from an English-language telecollaboration project between students at universities in Chile and California. This research found that the richest intercultural interactions involved events that could not have been foreseen: the immigrant rights demonstrations in the USA and the massive student…

  18. Text Chat as a Tool for Referential Questioning in Asperger Syndrome

    ERIC Educational Resources Information Center

    Rajendran, Gnanathusharan; Mitchell, Peter

    2006-01-01

    Purpose: This article reports a study in which referential communication in 11 individuals with Asperger syndrome (AS) and 11 controls was compared between text chat and telephone, using a route-solving task. Method: Participants deduced routes by asking closed questions, and the dependent variables were (a) accuracy in working out the route, (b)…

  19. The Effects of Synchronous CMC on Speaking Proficiency and Anxiety: Text versus Voice Chat

    ERIC Educational Resources Information Center

    Satar, H. Muge; Ozdener, Nesrin

    2008-01-01

    This article reports on a study investigating the use of 2 synchronous computer-mediated communication tools: text and voice chat. The experimental design employed 3 groups (text, voice, and control), each consisting of 30 novice-level secondary school learners of English as a foreign language. Over a 4-week period, the participants in the…

  20. Mobile-Based Chatting for Meaning Negotiation in Foreign Language Learning

    ERIC Educational Resources Information Center

    Castrillo, María Dolores; Martín-Monje, Elena; Bárcena, Elena

    2014-01-01

    This paper analyzes the adequacy of mobile chatting via Whatsapp for the enhancement of a type of spontaneous and colloquial written interaction which has a strong connection with oral discourse. This is part of a research project undertaken with Spanish students of German as a foreign language with a beginner's or quasi-beginner's level. The…

  1. Office Hours as You Like Them: Integrating Real-Time Chats into the Course Media Mix.

    ERIC Educational Resources Information Center

    McKeage, Kim

    2001-01-01

    Reports on one professor's use of integrated synchronous electronic office hours (i.e., a "chat room") with asynchronous course conferencing (i.e., email) in a class on introductory marketing. Describes its uses, limitations, benefits, potential problems, and results from a student survey. (EV)

  2. An Overview of Cultural Historical Activity Theory (CHAT) Use in Classroom Research 2000 to 2009

    ERIC Educational Resources Information Center

    Nussbaumer, Doris

    2012-01-01

    Western educational researchers have eagerly accepted activity theory (AT) also known as cultural historical activity theory (CHAT) to collect and analyze data in rich description of complex situations. As this theory is applicable to a wide variety of disciplines, this review is limited to education and specifically to qualitative studies of…

  3. Interaction, Facilitation, and Deep Learning in Cross-Cultural Chat: A Case Study

    ERIC Educational Resources Information Center

    Osman, Gihan; Herring, Susan C.

    2007-01-01

    This case study evaluates the potential of synchronous chat for deep learning in the context of a distance education program between two universities in different cultural contexts, with a focus on interaction and facilitation. Three rubrics--functional moves, social construction of knowledge, and teaching presence--were applied in a longitudinal…

  4. Connecting Developmental Constructions to the Internet: Identity Presentation and Sexual Exploration in Online Teen Chat Rooms

    ERIC Educational Resources Information Center

    Subrahmanyam, Kaveri; Smahel, David; Greenfield, Patricia

    2006-01-01

    The authors examined the online construction of identity and sexuality in a large sample of conversations from monitored and unmonitored teen chat rooms. More than half of the 583 participants (identified by a distinct screen name) communicated identity information, most frequently gender. In this way, participants compensated for the text-based…

  5. From "Hello" to Higher-Order Thinking: The Effect of Coaching and Feedback on Online Chats

    ERIC Educational Resources Information Center

    Stein, David S.; Wanstreet, Constance E.; Slagle, Paula; Trinko, Lynn A.; Lutz, Michelle

    2013-01-01

    This exploratory study examined the effect of a coaching and feedback intervention in teaching presence and social presence on higher-order thinking in an online community of inquiry. Coaching occurred before each chat, and feedback was provided immediately afterwards. The findings suggest that over time, the frequency of higher-order thinking…

  6. More than "Hello" and "Bye-Bye": Opening and Closing the Online Chats in Mandarin Chinese

    ERIC Educational Resources Information Center

    Zhang, De

    2014-01-01

    Reporting on a descriptive study on the first semester Chinese language learners' openings and closings in online chats with age-peer native speakers of Chinese, this paper demonstrates the great promise that telecollaboration holds for foreign language education, and argues for an increasing role of pragmatics in Chinese language…

  7. A Comparison of Chat Room Productivity: In-Class versus Out-of-Class

    ERIC Educational Resources Information Center

    Sanders, Robert

    2006-01-01

    Language production of Spanish students using synchronous CMC (chat) during class time was compared with that of students meeting outside of class. The study included about 100 participants enrolled in 10 sections of a first-quarter Spanish course at a US university. Students in the control group spent 30 minutes of their weekly class time in…

  8. Managing Mutual Orientation in the Absence of Physical Copresence: Multiparty Voice-Based Chat Room Interaction

    ERIC Educational Resources Information Center

    Jenks, Christopher Joseph; Brandt, Adam

    2013-01-01

    This study investigates the interactional work involved in ratifying mutual participation in online, multiparty, voice-based chat rooms. The purpose of this article is to provide a preliminary sketch of how talk and participation is managed in a spoken communication environment that comprises interactants who are not physically copresent but are…

  9. Outcomes of Chat and Discussion Board Use in Online Learning: A Research Synthesis

    ERIC Educational Resources Information Center

    Blackmon, Stephanie J.

    2012-01-01

    Online discussion boards are often used in traditional courses, hybrid courses, and fully online courses. Online chats and discussions can be particularly useful in fully online courses, as these communication connections are often students' only means of connecting with each other and sharing ideas in an open forum. While traditional face-to-face…

  10. Reenergising Professional Creativity from a CHAT Perspective: Seeing Knowledge and History in Practice

    ERIC Educational Resources Information Center

    Ellis, Viv

    2011-01-01

    This article offers a critical examination of aspects of a practice- and theory-developing intervention in the teacher education setting in England designed as a variation of Developmental Work Research. A positive case is argued for the distinctiveness of such cultural-historical activity theory (CHAT-) informed interventions and some points of…

  11. Pilot Susan L. Still chats with white room closeout crew member

    NASA Technical Reports Server (NTRS)

    1997-01-01

    KENNEDY SPACE CENTER, FLA. -- STS-83 Pilot Susan L. Still chats with white room closeout crew member Rene Arriens as she prepares to enter the Space Shuttle Columbia at Launch Pad 39A with assistance from closeout crew worker Bob Saulnier (behind Still).

  12. Polymorphisms of CHAT but not TFAM or VR22 are Associated with Alzheimer Disease Risk

    PubMed Central

    Gao, Lili; Zhang, Yan; Deng, Jinghua; Yu, Wenbing; Yu, Yunxia

    2016-01-01

    Background Alzheimer disease (AD) is a chronic neurodegenerative disease that is one of the most prevalent health problems among seniors. The cause of AD has not yet been elucidated, but many risk factors have been identified that might contribute to the pathogenesis and prognosis of AD. We conducted a meta-analysis of studies involving CHAT, TFAM, and VR22 polymorphisms and AD susceptibility to further understand the pathogenesis of AD. Material/Methods PubMed/Medline, Embase, Web of Science, the Cochrane Library, and Google Scholar were searched for relevant articles. Rs1880676, rs2177369, rs3810950, and rs868750 of CHAT; rs1937 and rs2306604 of TFAM; and rs10997691 and rs7070570 of VR22 are studied in this meta-analysis. Results A total of 51 case-control studies with 16 446 cases and 16 057 controls were enrolled. For CHAT, rs2177369 (G>A) in whites and rs3810950 (G>A) in Asians were found to be associated with AD susceptibility. No association was detected between rs1880676 and rs868750 and AD risk. For TFAM and VR22, no significant association was detected in studied single-nucleotide polymorphisms (SNPs). Conclusions Rs2177369 and rs3810950 of CHAT are associated with AD susceptibility, but rs1880676 and rs868750 are not. Rs1937 and rs2306604 of TFAM, and rs10997691 and rs7070570 of VR22 are not significantly associated with AD risk. PMID:27272392

  13. Combining Live Video and Audio Broadcasting, Synchronous Chat, and Asynchronous Open Forum Discussions in Distance Education

    ERIC Educational Resources Information Center

    Teng, Tian-Lih; Taveras, Marypat

    2004-01-01

    This article outlines the evolution of a unique distance education program that began as a hybrid--combining face-to-face instruction with asynchronous online teaching--and evolved to become an innovative combination of synchronous education using live streaming video, audio, and chat over the Internet, blended with asynchronous online discussions…

  14. Intercomprehension between Romance Languages and the Role of English: A Study of Multilingual Chat Rooms

    ERIC Educational Resources Information Center

    Melo-Pfeifer, Sílvia

    2014-01-01

    In this article, we focus on the role English plays in multilingual chat rooms in Romance Languages. We intend to demonstrate how English, even as forbidden language in this particular setting, is a mediation and a remediation tool. Our conclusions point out that: (1) English is an constructive resource in multilingual communication; (2) it has a…

  15. Collaborative Learning through Chat Discussions and Argument Diagrams in Secondary School

    ERIC Educational Resources Information Center

    Marttunen, Miika; Laurinen, Leena

    2007-01-01

    This study clarifies whether secondary school students develop their argumentation skills through reading and collaboration. The students first constructed an individual argument diagram on genetically modified organisms, read three articles, and improved their diagrams. Next, they engaged in a chat debate, reflected on their debate by…

  16. Prevalence of Autism Spectrum Phenomenology in Cornelia de Lange and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Moss, Joanna F.; Oliver, Chris; Berg, Katy; Kaur, Gurmeash; Jephcott, Lesley; Cornish, Kim

    2008-01-01

    Autism spectrum disorder characteristics have not been evaluated in Cornelia de Lange and Cri du Chat syndromes using robust assessments. The Autism Diagnostic Observation Schedule and Social Communication Questionnaire were administered to 34 participants with Cornelia de Lange syndrome and a comparison group of 23 participants with Cri du Chat…

  17. `Up-regulation of histone acetylation induced by social defeat mediates the conditioned rewarding effects of cocaine.

    PubMed

    Montagud-Romero, S; Montesinos, J; Pascual, M; Aguilar, M A; Roger-Sanchez, C; Guerri, C; Miñarro, J; Rodríguez-Arias, M

    2016-10-01

    Social defeat (SD) induces a long-lasting increase in the rewarding effects of psychostimulants measured using the self-administration and conditioned place procedures (CPP). However, little is known about the epigenetic changes induced by social stress and about their role in the increased response to the rewarding effects of psychostimulants. Considering that histone acetylation regulates transcriptional activity and contributes to drug-induced behavioral changes, we addressed the hypothesis that SD induces transcriptional changes by histone modifications associated with the acquisition of place conditioning. After a fourth defeat, H3(K9) acetylation was decreased in the hippocampus, while there was an increase of HAT and a decrease of HDAC levels in the cortex. Three weeks after the last defeat, mice displayed an increase in histone H4(K12) acetylation and an upregulation of histone acetyl transferase (HAT) activity in the hippocampus. In addition, H3(K4)me3, which is closely associated with transcriptional initiation, was also augmented in the hippocampus three weeks after the last defeat. Inhibition of HAT by curcumin (100mg/kg) before each SD blocked the increase in the conditioned reinforcing effects of 1mg/kg of cocaine, while inhibition of HDAC by valproic acid (500mg/kg) before social stress potentiated cocaine-induced CPP. Preference was reinstated when animals received a priming dose of 0.5mg/kg of cocaine, an effect that was absent in untreated defeated mice. These results suggest that the experience of SD induces chromatin remodeling, alters histone acetylation and methylation, and modifies the effects of cocaine on place conditioning. They also point to epigenetic mechanisms as potential avenues leading to new treatments for the long-term effects of social stress on drug addiction. PMID:27180319

  18. Alert: the dark side of chats--internet without boundaries.

    PubMed

    Aderet, Avshalom

    2009-01-01

    The web has some unique advantages: It eliminates barriers of space and time; information flows quicker and is more accessible to all; the markets are more effective; community and interpersonal communication is more evolved. However, the web is also anonymous, without supervision, freedom of speech is exploited, minors and other web users are exploited, racism and prejudice are encouraged. These manifestations of violence not only hurt many people but actually pose a threat to the existence of the web as a place for exchanging ideas and thoughts, as a tool for relaying messages in a liberal and democratic fashion. Today, it is not legally possible to stop any discussion group or chats, like the one in which Eran participated, which develop dialogues regarding death or suicide. A wise and proper use of the web will be achieved by agreements and not enforcement. It is a process of education in its widest meaning that will be accomplished through the acceptance of norms. Proper use of the web will be possible when all sides--users, site owners and suppliers--willingly commit to values of mutual respect, decency and protection of individual fundamental rights to freedom. The web, which is a great blessing to the communication between people, organizations and cultures, carries with it substantial risks, especially to young users. The rapid expansion of the web and the increase in the number of users has brought many social-ideological dangers alongside the many advantages. In order to deal with these issues, a few years ago I initiated an association known as Eshnav (www.eshnav.org.il) which acts to increase public awareness to the risks and dangers of the web. Eshnav's mission, established to commemorate Eran's memory, is to promote public awareness to the positive and negative aspects of using the web on society and its values, and to promote the wise and safe use of the web. Eran was in great distress and needed empathy, encouragement and support. Sadly, when his

  19. Polymorphic variation in CHAT gene modulates general cognitive ability: An association study with random student cohort.

    PubMed

    Liu, Xu; Shi, Yuanyu; Niu, Binbin; Shi, Zhangyan; Li, Junlin; Ma, Zhe; Wang, Jian; Gong, Pingyuan; Zheng, Anyun; Zhang, Fuchang; Gao, Xiaocai; Zhang, Kejin

    2016-03-23

    The choline O-acetyltransferase (CHAT) gene has been associated with various human disorders that involve cognitive impairment or deficiency. However, the influence of disease-associated variants of CHAT on normal individuals remains dubious. Here we demonstrated the impact of CHAT sequence variants (G-120A) on general human cognitive ability in a cohort of 750 Chinese undergraduate students. A multiple choice questionnaire was used to obtain basic demographic information, such as parents' occupations and education levels. We also administered and scored the Raven's Standard Progressive Matrices (RSPM). A one-way analysis of variance (ANOVA) and Kruskal-Wallis test (K-W) revealed a significant association between sequence polymorphisms of G-120A and individuals' Raven score (p=0.031 for ANOVA and p=0.026 for K-W tests). Moreover, further hierarchical analysis showed a similar trend in the association between G-120A variants and Raven scores only in the female subjects (p=0.008 for ANOVA and p=0.024 for K-W tests) but not in the male subjects. The results of a multiple linear regression confirmed that after we controlled gender, age, birthplace and other non-genetic factors, CHAT G-120A polymorphisms still significantly influenced individual Raven scores (B=-0.70, SE=0.28, t=-2.50, p=0.013). Our results demonstrated that sequence variants of CHAT were associated with human cognitive ability in not only patients with psychiatric disorders but also normal healthy individuals. However, some issues remained indeterminable, such as gender differences and the extent of the influence on individuals' general cognitive abilities; thus, the further research using an independent random sample was required. PMID:26854842

  20. Gene encoding acetyl-coenzyme A carboxylase

    DOEpatents

    Roessler, P.G.; Ohlrogge, J.B.

    1996-09-24

    A DNA encoding an acetyl-coenzyme A carboxylase (ACCase) from a photosynthetic organism and functional derivatives are disclosed which are resistant to inhibition from certain herbicides. This gene can be placed in organisms to increase their fatty acid content or to render them resistant to certain herbicides. 5 figs.

  1. 21 CFR 172.828 - Acetylated monoglycerides.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... molecular distillation or by steam stripping; or (2) The direct acetylation of edible monoglycerides with acetic anhydride without the use of catalyst or molecular distillation, and with the removal by vacuum distillation, if necessary, of the acetic acid, acetic anhydride, and triacetin. (b) The food additive has...

  2. 21 CFR 172.828 - Acetylated monoglycerides.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... molecular distillation or by steam stripping; or (2) The direct acetylation of edible monoglycerides with acetic anhydride without the use of catalyst or molecular distillation, and with the removal by vacuum distillation, if necessary, of the acetic acid, acetic anhydride, and triacetin. (b) The food additive has...

  3. 21 CFR 172.828 - Acetylated monoglycerides.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... molecular distillation or by steam stripping; or (2) The direct acetylation of edible monoglycerides with acetic anhydride without the use of catalyst or molecular distillation, and with the removal by vacuum distillation, if necessary, of the acetic acid, acetic anhydride, and triacetin. (b) The food additive has...

  4. 21 CFR 172.828 - Acetylated monoglycerides.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... molecular distillation or by steam stripping; or (2) The direct acetylation of edible monoglycerides with acetic anhydride without the use of catalyst or molecular distillation, and with the removal by vacuum distillation, if necessary, of the acetic acid, acetic anhydride, and triacetin. (b) The food additive has...

  5. Gene encoding acetyl-coenzyme A carboxylase

    DOEpatents

    Roessler, Paul G.; Ohlrogge, John B.

    1996-01-01

    A DNA encoding an acetyl-coenzyme A carboxylase (ACCase) from a photosynthetic organism and functional derivatives thereof which are resistant to inhibition from certain herbicides. This gene can be placed in organisms to increase their fatty acid content or to render them resistant to certain herbicides.

  6. Interrelationship between anionic and cationic forms of glutathione S-transferases of human liver.

    PubMed Central

    Awasthi, Y C; Dao, D D; Saneto, R P

    1980-01-01

    Human liver glutathione S-transferases (GSH S-transferases) were fractionated into cationic and anionic proteins. During fractionation with (NH4)2SO4 the anionic GSH S-transferases are concentrated in the 65%-saturated-(NH4)2SO4 fraction, whereas the cationic GSH S-transferases separate in the 80%-saturated-(NH4)2SO4 fraction. From the 65%-saturated-(NH4)2SO4 fraction two new anionic GSH S-transferases, omega and psi, were purified to homogeneity by using ion-exchange chromatography on DEAE-cellulose, Sephadex G-200 gel filtration, affinity chromatography on GSH bound to epoxy-activated Sepharose and isoelectric focusing. By a similar procedure, cationic GSH S-transferases were purified from the 80%-saturated-(NH4)2SO4 fraction. Isoelectric points of GSH S-transferases omega and psi are 4.6 and 5.4 respectively. GSH S-transferase omega is the major anionic GSH S-transferase of human liver, whereas GSH S-transferase psi is present only in traces. The subunit mol.wt. of GSH S-transferase omega is about 22500, whereas that of cationic GSH S-transferases is about 24500. Kinetic and structural properties as well as the amino acid composition of GSH S-transferase omega are described. The antibodies raised against cationic GSH S-transferases cross-react with GSH S-transferase omega. There are significant differences between the catalytic properties of GSH S-transferase omega and the cationic GSH S-transferases. GSH peroxidase II activity is displayed by all five cationic GSH S-transferases, whereas both anionic GSH S-transferases do not display this activity. Images Fig. 3. PMID:7470087

  7. Functional analysis of N-linking oligosaccharyl transferase enzymes encoded by deep-sea vent proteobacteria.

    PubMed

    Mills, Dominic C; Jervis, Adrian J; Abouelhadid, Sherif; Yates, Laura E; Cuccui, Jon; Linton, Dennis; Wren, Brendan W

    2016-04-01

    Bacterial N-linking oligosaccharyl transferases (OTase enzymes) transfer lipid-linked glycans to selected proteins in the periplasm and were first described in the intestinal pathogen Campylobacter jejuni, a member of the ε-proteobacteria-subdivision of bacteria. More recently, orthologues from other ε-proteobacterial Campylobacter and Helicobacter species and a δ-proteobacterium, Desulfovibrio desulfuricans, have been described, suggesting that these two subdivisions of bacteria may be a source of further N-linked protein glycosylation systems. Whole-genome sequencing of both ε- and δ-proteobacteria from deep-sea vent habitats, a rich source of species from these subdivisions, revealed putative ORFs encoding OTase enzymes and associated adjacent glycosyltransferases similar to the C. jejuni N-linked glycosylation locus. We expressed putative OTase ORFs from the deep-sea vent species Nitratiruptor tergarcus, Sulfurovum lithotrophicum and Deferribacter desulfuricans in Escherichia coli and showed that they were able to functionally complement the C. jejuni OTase, CjPglB. The enzymes were shown to possess relaxed glycan specificity, transferring diverse glycan structures and demonstrated different glycosylation sequon specificities. Additionally, a permissive D. desulfuricans acceptor protein was identified, and we provide evidence that the N-linked glycan synthesized by N. tergarcus and S. lithotrophicum contains an acetylated sugar at the reducing end. This work demonstrates that deep-sea vent bacteria encode functional N-glycosylation machineries and are a potential source of biotechnologically important OTase enzymes. PMID:26610891

  8. Functional analysis of N-linking oligosaccharyl transferase enzymes encoded by deep-sea vent proteobacteria

    PubMed Central

    Mills, Dominic C.; Jervis, Adrian J.; Abouelhadid, Sherif; Yates, Laura E.; Cuccui, Jon; Linton, Dennis; Wren, Brendan W.

    2016-01-01

    Bacterial N-linking oligosaccharyl transferases (OTase enzymes) transfer lipid-linked glycans to selected proteins in the periplasm and were first described in the intestinal pathogen Campylobacter jejuni, a member of the ε-proteobacteria-subdivision of bacteria. More recently, orthologues from other ε-proteobacterial Campylobacter and Helicobacter species and a δ-proteobacterium, Desulfovibrio desulfuricans, have been described, suggesting that these two subdivisions of bacteria may be a source of further N-linked protein glycosylation systems. Whole-genome sequencing of both ε- and δ-proteobacteria from deep-sea vent habitats, a rich source of species from these subdivisions, revealed putative ORFs encoding OTase enzymes and associated adjacent glycosyltransferases similar to the C. jejuni N-linked glycosylation locus. We expressed putative OTase ORFs from the deep-sea vent species Nitratiruptor tergarcus, Sulfurovum lithotrophicum and Deferribacter desulfuricans in Escherichia coli and showed they were able to functionally complement the C. jejuni OTase, CjPglB . The enzymes were shown to possess relaxed glycan specificity, transferring diverse glycan structures and demonstrated different glycosylation sequon specificities. Additionally a permissive D. desulfuricans acceptor protein was identified, and we provide evidence that the N-linked glycan synthesised by N. tergarcus and S. lithotrophicum contains an acetylated sugar at the reducing end. This work demonstrates that deep-sea vent bacteria encode functional N-glycosylation machineries and are a potential source of biotechnologically important OTase enzymes. PMID:26610891

  9. Terminal Deoxynucleotidyl Transferase: The Story of a Misguided DNA Polymerase

    PubMed Central

    Motea, Edward A.; Berdis, Anthony J.

    2009-01-01

    Nearly every DNA polymerase characterized to date exclusively catalyzes the incorporation of mononucleotides into a growing primer using a DNA or RNA template as a guide to direct each incorporation event. There is, however, one unique DNA polymerase designated terminal deoxynucleotidyl transferase that performs DNA synthesis using only single-stranded DNA as the nucleic acid substrate. In this chapter, we review the biological role of this enigmatic DNA polymerase and the biochemical mechanism for its ability to perform DNA synthesis in the absence of a templating strand. We compare and contrast the molecular events for template-independent DNA synthesis catalyzed by terminal deoxynucleotidyl transferase with other well-characterized DNA polymerases that perform template-dependent synthesis. This includes a quantitative inspection of how terminal deoxynucleotidyl transferase binds DNA and dNTP substrates, the possible involvement of a conformational change that precedes phosphoryl transfer, and kinetic steps that are associated with the release of products. These enzymatic steps are discussed within the context of the available structures of terminal deoxynucleotidyl transferase in the presence of DNA or nucleotide substrate. In addition, we discuss the ability of proteins involved in replication and recombination to regulate the activity of the terminal deoxynucleotidyl transferase. Finally, the biomedical role of this specialized DNA polymerase is discussed focusing on its involvement in cancer development and its use in biomedical applications such as labeling DNA for detecting apoptosis. PMID:19596089

  10. Inhibition of hepatic glutathione transferases by propylthiouracil and its metabolites.

    PubMed

    Kariya, K; Sawahata, T; Okuno, S; Lee, E

    1986-05-01

    The effects of propylthiouracil (PTU) and its metabolites on the activity of GSH transferases were examined using rat liver cytosol. PTU inhibited the enzyme activity toward both CDNB and DCNB in a concentration-dependent manner. At the concentration of 10 mM, PTU caused 25% inhibition, which was the maximum effect. PTU derivatives such as propyluracil and thiouracil showed the same effect as the parent compound. On the other hand, S-oxides of PTU such as PTU-SO2 and PTU-SO3, which were chemically synthesized by the oxidation of PTU, were more potent inhibitors of GSH transferases than the parent PTU. A significant inhibition was observed at a concentration of 0.1 mM of PTU S-oxides. At a concentration of 10 mM the S-oxides caused an 80% inhibition of the enzyme activity. PTU inhibited the transferase activity by competing with GSH but the S-oxides of PTU acted by another mechanism. In contrast to the effect on GSH transferases, PTU-SO3 had a weak inhibitory effect on GSH peroxidase activity. Thus, oxidation of PTU leads to products which are potent inhibitors of GSH transferases. PMID:3707612

  11. Estimation of volume and mass and of changes in volume and mass of selected chat piles in the Picher mining district, Ottawa County, Oklahoma, 2005-10

    USGS Publications Warehouse

    Smith, S. Jerrod

    2013-01-01

    From the 1890s through the 1970s the Picher mining district in northeastern Ottawa County, Oklahoma, was the site of mining and processing of lead and zinc ore. When mining ceased in about 1979, as much as 165–300 million tons of mine tailings, locally referred to as “chat,” remained in the Picher mining district. Since 1979, some chat piles have been mined for aggregate materials and have decreased in volume and mass. Currently (2013), the land surface in the Picher mining district is covered by thousands of acres of chat, much of which remains on Indian trust land owned by allottees. The Bureau of Indian Affairs manages these allotted lands and oversees the sale and removal of chat from these properties. To help the Bureau of Indian Affairs better manage the sale and removal of chat, the U.S. Geological Survey, in cooperation with the Bureau of Indian Affairs, estimated the 2005 and 2010 volumes and masses of selected chat piles remaining on allotted lands in the Picher mining district. The U.S. Geological Survey also estimated the changes in volume and mass of these chat piles for the period 2005 through 2010. The 2005 and 2010 chat-pile volume and mass estimates were computed for 34 selected chat piles on 16 properties in the study area. All computations of volume and mass were performed on individual chat piles and on groups of chat piles in the same property. The Sooner property had the greatest estimated volume (4.644 million cubic yards) and mass (5.253 ± 0.473 million tons) of chat in 2010. Five of the selected properties (Sooner, Western, Lawyers, Skelton, and St. Joe) contained estimated chat volumes exceeding 1 million cubic yards and estimated chat masses exceeding 1 million tons in 2010. Four of the selected properties (Lucky Bill Humbah, Ta Mee Heh, Bird Dog, and St. Louis No. 6) contained estimated chat volumes of less than 0.1 million cubic yards and estimated chat masses of less than 0.1 million tons in 2010. The total volume of all

  12. Fluorescent techniques for discovery and characterization of phosphopantetheinyl transferase inhibitors

    PubMed Central

    Kosa, Nicolas M.; Foley, Timothy L.; Burkart, Michael D.

    2016-01-01

    Phosphopantetheinyl transferase (E.C. 2.7.8.-) activates biosynthetic pathways that synthesize both primary and secondary metabolites in bacteria. Inhibitors of these enzymes have the potential to serve as antibiotic compounds that function through a unique mode of action and possess clinical utility. Here we report a direct and continuous assay for this enzyme class based upon monitoring polarization of a fluorescent phosphopantetheine analog as it is transferred from a low molecular weight coenzyme A substrate to higher molecular weight protein acceptor. We demonstrate the utility of this method for the biochemical characterization of phosphopantetheinyl transferase Sfp, a canonical representative from this class. We also establish the portability of this technique to other homologs by adapting the assay to function with the human phosphopantetheinyl transferase, a target for which a microplate detection method does not currently exist. Comparison of these targets provides a basis to predict therapeutic index of inhibitor candidates and offers a valuable characterization of enzyme activity. PMID:24192555

  13. Thioltransferase activity of bovine lens glutathione S-transferase.

    PubMed Central

    Dal Monte, M; Cecconi, I; Buono, F; Vilardo, P G; Del Corso, A; Mura, U

    1998-01-01

    A Mu-class glutathione S-transferase purified to electrophoretic homogeneity from bovine lens displayed thioltransferase activity, catalysing the transthiolation reaction between GSH and hydroxyethyldisulphide. The thiol-transfer reaction is composed of two steps, the formation of GSSG occurring through the generation of an intermediate mixed disulphide between GSH and the target disulphide. Unlike glutaredoxin, which is only able to catalyse the second step of the transthiolation process, glutathioneS-transferase catalyses both steps of the reaction. Data are presented showing that bovine lens glutathione S-transferase and rat liver glutaredoxin, which was used as a thioltransferase enzyme model, can operate in synergy to catalyse the GSH-dependent reduction of hydroxyethyldisulphide. PMID:9693102

  14. Immunity status of adults and children against poliomyelitis virus type 1 strains CHAT and Sabin (LSc-2ab) in Germany

    PubMed Central

    2010-01-01

    Background In October 2007, the working group CEN/TC 216 of the European Committee for standardisation suggested that the Sabin oral poliovirus vaccine type 1 strain (LSc-2ab) presently used for virucidal tests should be replaced by another attenuated vaccine poliovirus type 1 strain, CHAT. Both strains were historically used as oral vaccines, but the Sabin type 1 strain was acknowledged to be more attenuated. In Germany, vaccination against poliomyelitis was introduced in 1962 using the oral polio vaccine (OPV) containing Sabin strain LSc-2ab. The vaccination schedule was changed from OPV to an inactivated polio vaccine (IPV) containing wild polio virus type 1 strain Mahoney in 1998. In the present study, we assessed potential differences in neutralising antibody titres to Sabin and CHAT in persons with a history of either OPV, IPV, or OPV with IPV booster. Methods Neutralisation poliovirus antibodies against CHAT and Sabin 1 were measured in sera of 41 adults vaccinated with OPV. Additionally, sera from 28 children less than 10 years of age and immunised with IPV only were analysed. The neutralisation assay against poliovirus was performed according to WHO guidelines. Results The neutralisation activity against CHAT in adults with OPV vaccination history was significantly lower than against Sabin poliovirus type 1 strains (Wilcoxon signed-rank test P < 0.025). In eight sera, the antibody titres measured against CHAT were less than 8, although the titre against Sabin 1 varied between 8 and 64. Following IPV booster, anti-CHAT antibodies increased rapidly in sera of CHAT-negative adults with OPV history. Sera from children with IPV history neutralised CHAT and Sabin 1 strains equally. Conclusion The lack of neutralising antibodies against the CHAT strain in persons vaccinated with OPV might be associated with an increased risk of reinfection with the CHAT polio virus type 1, and this implies a putative risk of transmission of the virus to polio-free communities. We

  15. Dynamic Protein Acetylation in Plant–Pathogen Interactions

    PubMed Central

    Song, Gaoyuan; Walley, Justin W.

    2016-01-01

    Pathogen infection triggers complex molecular perturbations within host cells that results in either resistance or susceptibility. Protein acetylation is an emerging biochemical modification that appears to play central roles during host–pathogen interactions. To date, research in this area has focused on two main themes linking protein acetylation to plant immune signaling. Firstly, it has been established that proper gene expression during defense responses requires modulation of histone acetylation within target gene promoter regions. Second, some pathogens can deliver effector molecules that encode acetyltransferases directly within the host cell to modify acetylation of specific host proteins. Collectively these findings suggest that the acetylation level for a range of host proteins may be modulated to alter the outcome of pathogen infection. This review will focus on summarizing our current understanding of the roles of protein acetylation in plant defense and highlight the utility of proteomics approaches to uncover the complete repertoire of acetylation changes triggered by pathogen infection. PMID:27066055

  16. Internet Relay Chat as a Tool in the Autonomous Development of ESL Learners' English Language Ability: An Exploratory Study

    ERIC Educational Resources Information Center

    Coniam, David; Wong, Richard

    2004-01-01

    This pilot study explores the use of Internet Relay Chat facilities such as ICQ in an independent-use mode, as a vehicle for potential English language enhancement. In a small-scale study, a number of Hong Kong secondary school students (Grades 7-10) agreed to participate in an on-line "chatting" programme (in a text-only mode) for a minimum of 20…

  17. The neurobiology of acetyl-L-carnitine.

    PubMed

    Traina, Giovanna

    2016-01-01

    A large body of evidence points to the positive effects of dietary supplementation of acetyl-L-carnitine (ALC). Its use has shown health benefits in neuroinflammation, which is a common denominator in a host of neurodegenerative diseases. ALC is the principal acetyl ester of L-Carnitine (LC), and it plays an essential role in intermediary metabolism, acting as a donor of acetyl groups and facilitating the transfer of fatty acids from cytosol to mitochondria during beta-oxidation. Dietary supplementation of ALC exerts neuroprotective, neurotrophic, antidepressive and analgesic effects in painful neuropathies. ALC also has antioxidant and anti-apoptotic activity. Moreover, ALC exhibits positive effects on mitochondrial metabolism, and shows promise in the treatment of aging and neurodegenerative pathologies by slowing the progression of mental deterioration. In addition, ALC plays neuromodulatory effects on both synaptic morphology and synaptic transmission. These effects are likely due to affects of ALC through modulation of gene expression on several targets in the central nervous system. Here, we review the current state of knowledge on effects of ALC in the nervous system. PMID:27100509

  18. Enhancement of lysine acetylation accelerates wound repair

    PubMed Central

    Spallotta, Francesco; Cencioni, Chiara; Straino, Stefania; Sbardella, Gianluca; Castellano, Sabrina; Capogrossi, Maurizio C; Martelli, Fabio; Gaetano, Carlo

    2013-01-01

    In physiopathological conditions, such as diabetes, wound healing is significantly compromised and chronic complications, including ulcers, may occur. In a mouse model of skin repair, we recently reported that wound treatment with Sirtuin activators and class I HDAC inhibitors induced keratinocyte proliferation and enhanced healing via a nitric oxide (NO) dependent mechanism. We observed an increase in total protein acetylation in the wound area, as determined by acetylation of α-tubulin and histone H3 Lysine 9. We reasoned that this process activated cell function as well as regulated gene expression to foster tissue repair. We report here that the direct activation of P300/CBP-associated factor (PCAF) by the histone acetylase activator pentadecylidenemalonate 1b (SPV-106) induced Lysine acetylation in the wound area. This intervention was sufficient to enhance repair process by a NO-independent mechanism. Hence, an impairment of PCAF and/or other GCN5 family acetylases may delay skin repair in physiopathological conditions. PMID:24265859

  19. Fragrance material review on acetyl cedrene.

    PubMed

    Scognamiglio, J; Letizia, C S; Politano, V T; Api, A M

    2013-12-01

    A toxicologic and dermatologic review of acetyl cedrene when used as a fragrance ingredient is presented. Acetyl cedrene is a member of the fragrance structural group Alkyl Cyclic Ketones. The generic formula for this group can be represented as (R1)(R2)CO. These fragrances can be described as being composed of an alkyl, R1, and various substituted and bicyclic saturated or unsaturated cyclic hydrocarbons, R2, in which one of the rings may include up to 12 carbons. Alternatively, R2 may be a carbon bridge of C2-C4 carbon chain length between the ketone and cyclic hydrocarbon. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for acetyl cedrene were evaluated then summarized and includes physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, photoallergy, toxicokinetics, repeated dose, reproductive toxicity, and genotoxicity data. A safety assessment of the entire Alkyl Cyclic Ketones will be published simultaneously with this document; please refer to Belsito et al. (2013) (Belsito, D., Bickers, D., Bruze, M., Calow, P., Dagli, M., Fryer, A.D., Greim, H., Miyachi, Y., Saurat, J.H., Sipes, I.G., 2013. A Toxicologic and Dermatologic Assessment of Alkyl Cyclic Ketones When Used as Fragrance Ingredients. Submitted with this manuscript.) for an overall assessment of the safe use of this material and all Alkyl Cyclic Ketones in fragrances. PMID:23907023

  20. Vers la génération de chats de Schrödinger optiques

    NASA Astrophysics Data System (ADS)

    Ourjoumtsev, A.; Laurat, J.; Tualle-Brouri, R.; Grangier, Ph.

    2006-10-01

    Nous réalisons actuellement une implémentation expérimentale d'un protocole de création de petits chats de Schrödinger optiques. Ces états présentent un fort intérêt dans le domaine de l'information quantique, notamment dans des protocoles de calcul universel ou de métrologie quantique [1,2].

  1. Le syndrome de Cri du Chat : A propos d’une observation

    PubMed Central

    Ouldim, Karim; Samri, Imane; Bouguenouch, Laila; Hamdaoui, Hasna; Otmani, Ihsan El; Hbibi, Mohamed; Chaouki, Sana; Hida, Moustapha

    2012-01-01

    Le syndrome du Cri du Chat (Cri du Chat syndrome, CdCS) est une anomalie chromosomique résultant d’une délétion de taille variable de l’extrémité du bras court du chromosome 5 (5p), incluant une région critique située en p15.2. Il représente une des délétions chromosomiques les plus fréquentes, son incidence dans la population générale est de 1/20 000 à 1/50 000. Les caractéristiques cliniques comprennent un cri monochromatique aigu, une microcéphalie, une dysmorphie cranio-faciale caractéristique évoluant avec l’âge et un retard mental et psychomoteur important. La taille de la délétion est variable, Le traitement est fonction des différents symptômes. Un remaniement chromosomique parental est retrouvé dans 12% des cas et la majorité des délétions responsables de la maladie du cri-du-chat surviennent de novo. Nous présentons une observation d’un syndrome du Cri du Chat, confirmé par caryotype métaphasique (46,XY,del(5)(p13) de novo). A travers cette observation nous mettrons à jour, les actualités scientifiques de ce rare syndrome, ainsi que la place des explorations cytogénétiques dans le diagnostic précis et le conseil génétique des syndromes dysmorphiques. PMID:22368747

  2. STS-79 MISSION SPECIALIST JOHN E. BLAHA AND COMMANDER WILLIAM F. READDY CHAT DURING EMERGENCY EGRESS

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-79 Mission Specialist John E. Blaha (left) and Mission Commander William F. Readdy chat during emergency egress training at the 195-foot (59-meter) level of Launch Pad 39A. The training is part of their Terminal Countdown Demonstration Test (TCDT) activities. A dress rehearsal for launch, the TCDT culminates with a simulated countdown. The Space Shuttle Atlantis is undergoing preparations for liftoff on STS-79 no earlier than Sept. 12.

  3. METAL-INDUCED INHIBITION OF GLUTATHIONE S-TRANSFERASES

    EPA Science Inventory

    The glutathione S-transferases comprise a group of multi-functional enzymes involved in the biotransformation/detoxication of a broad spectrum of hydrophobic compounds bearing an electrophilic center. The enzymes facilitate the nucleophilic attack of the -SH group of reduced glut...

  4. Rational design of an organometallic glutathione transferase inhibitor

    SciTech Connect

    Ang, W.H.; Parker, L.J.; De Luca, A.; Juillerat-Jeanneret, L.; Morton, C.J.; LoBello, M.; Parker, M.W.; Dyson, P.J.

    2010-08-17

    A hybrid organic-inorganic (organometallic) inhibitor was designed to target glutathione transferases. The metal center is used to direct protein binding, while the organic moiety acts as the active-site inhibitor. The mechanism of inhibition was studied using a range of biophysical and biochemical methods.

  5. GLUTATHIONE S-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE

    EPA Science Inventory

    GLUTATHIONE s-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE. M K Ross1 and R A Pegram2. 1Curriculum in Toxicology, University of North Carolina at Chapel Hill; 2Experimental Toxicology Division, NHEERL/ORD, United States Environmental Protection Agency, Research Triangl...

  6. 21 CFR 862.1535 - Ornithine carbamyl transferase test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ornithine carbamyl transferase test system. 862.1535 Section 862.1535 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1535 Ornithine...

  7. Genetics Home Reference: succinyl-CoA:3-ketoacid CoA transferase deficiency

    MedlinePlus

    ... CoA:3-ketoacid CoA transferase deficiency succinyl-CoA:3-ketoacid CoA transferase deficiency Enable Javascript to view ... PDF Open All Close All Description Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is an inherited ...

  8. Effects of curcumin on cytochrome P450 and glutathione S-transferase activities in rat liver.

    PubMed

    Oetari, S; Sudibyo, M; Commandeur, J N; Samhoedi, R; Vermeulen, N P

    1996-01-12

    The stability of curcumin, as well as the interactions between curcumin and cytochrome P450s (P450s) and glutathione S-transferases (GSTs) in rat liver, were studied. Curcumin is relatively unstable in phosphate buffer at pH 7.4. The stability of curcumin was strongly improved by lowering the pH or by adding glutathione (GSH), N-acetyl L-cysteine (NAC), ascorbic acid, rat liver microsomes, or rat liver cytosol. Curcumin was found to be a potent inhibitor of rat liver P450 1A1/1A2 measured as ethoxyresorufin deethylation (EROD) activity in beta-naphthoflavone (beta NF)-induced microsomes, a less potent inhibitor of P450 2B1/2B2, measured as pentoxyresorufin depentylation (PROD) activity in phenobarbital (PB)-induced microsomes and a weak inhibitor of P450 2E1, measured as p-nitrophenol (PNP) hydroxylation activity in pyrazole-induced microsomes. Ki values were 0.14 and 76.02 microM for the EROD- and PROD-activities, respectively, and 30 microM of curcumin inhibited only 9% of PNP-hydroxylation activity. In ethoxyresorufin deethylation (EROD) and pentoxyresorufin depentylation (PROD) experiments, curcumin showed a competitive type of inhibition. Curcumin was also a potent inhibitor of glutathione S-transferase (GST) activity in cytosol from liver of rats treated with phenobarbital (PB), beta-naphthoflavone (beta NF) and pyrazole (Pyr), when measured towards 1-chloro-2,4-dinitrobenzene (CDNB) as substrate. In liver cytosol from rats treated with phenobarbital (PB), curcumin inhibited GST activity in a mixed-type manner with a Ki of 5.75 microM and Ki of 12.5 microM. In liver cytosol from rats treated with pyrazole (Pyr) or beta-naphthoflavone (beta NF), curcumin demonstrated a competitive type of inhibition with Ki values of 1.79 microM and 2.29 microM, respectively. It is concluded that these strong inhibitory properties of curcumin towards P450s and GSTs, in addition to its well-known antioxidant activity, may help explain the previously observed anticarcinogenic

  9. Optimizing Fracture Treatments in a Mississippian "Chat" Reservoir, South-Central Kansas

    SciTech Connect

    K. David Newell; Saibal Bhattacharya; Alan Byrnes; W. Lynn Watney; Willard Guy

    2005-10-01

    This project is a collaboration of Woolsey Petroleum Corporation (a small independent operator) and the Kansas Geological Survey. The project will investigate geologic and engineering factors critical for designing hydraulic fracture treatments in Mississippian ''chat'' reservoirs. Mississippian reservoirs, including the chat, account for 159 million m3 (1 billion barrels) of the cumulative oil produced in Kansas. Mississippian reservoirs presently represent {approx}40% of the state's 5.6*106m3 (35 million barrels) annual production. Although geographically widespread, the ''chat'' is a heterogeneous reservoir composed of chert, cherty dolomite, and argillaceous limestone. Fractured chert with micro-moldic porosity is the best reservoir in this 18- to 30-m-thick (60- to 100-ft) unit. The chat will be cored in an infill well in the Medicine Lodge North field (417,638 m3 [2,626,858 bbls] oil; 217,811,000 m3 [7,692,010 mcf] gas cumulative production; discovered 1954). The core and modern wireline logs will provide geological and petrophysical data for designing a fracture treatment. Optimum hydraulic fracturing design is poorly defined in the chat, with poor correlation of treatment size to production increase. To establish new geologic and petrophysical guidelines for these treatments, data from core petrophysics, wireline logs, and oil-field maps will be input to a fracture-treatment simulation program. Parameters will be established for optimal size of the treatment and geologic characteristics of the predicted fracturing. The fracturing will be performed and subsequent wellsite tests will ascertain the results for comparison to predictions. A reservoir simulation program will then predict the rate and volumetric increase in production. Comparison of the predicted increase in production with that of reality, and the hypothetical fracturing behavior of the reservoir with that of its actual behavior, will serve as tests of the geologic and petrophysical

  10. Acetylation and characterization of spruce (Picea abies) galactoglucomannans.

    PubMed

    Xu, Chunlin; Leppänen, Ann-Sofie; Eklund, Patrik; Holmlund, Peter; Sjöholm, Rainer; Sundberg, Kenneth; Willför, Stefan

    2010-04-19

    Acetylated galactoglucomannans (GGMs) are the main hemicellulose type in most softwood species and can be utilized as, for example, bioactive polymers, hydrocolloids, papermaking chemicals, or coating polymers. Acetylation of spruce GGM using acetic anhydride with pyridine as catalyst under different conditions was conducted to obtain different degrees of acetylation on a laboratory scale, whereas, as a classic method, it can be potentially transferred to the industrial scale. The effects of the amount of catalyst and acetic anhydride, reaction time, temperature and pretreatment by acetic acid were investigated. A fully acetylated product was obtained by refluxing GGM for two hours. The structures of the acetylated GGMs were determined by SEC-MALLS/RI, (1)H and (13)C NMR and FTIR spectroscopy. NMR studies also indicated migration of acetyl groups from O-2 or O-3 to O-6 after a heating treatment in a water bath. The thermal stability of the products was investigated by DSC-TGA. PMID:20144827

  11. Chemical Reactivity Window Determines Prodrug Efficiency toward Glutathione Transferase Overexpressing Cancer Cells.

    PubMed

    van Gisbergen, Marike W; Cebula, Marcus; Zhang, Jie; Ottosson-Wadlund, Astrid; Dubois, Ludwig; Lambin, Philippe; Tew, Kenneth D; Townsend, Danyelle M; Haenen, Guido R M M; Drittij-Reijnders, Marie-José; Saneyoshi, Hisao; Araki, Mika; Shishido, Yuko; Ito, Yoshihiro; Arnér, Elias S J; Abe, Hiroshi; Morgenstern, Ralf; Johansson, Katarina

    2016-06-01

    Glutathione transferases (GSTs) are often overexpressed in tumors and frequently correlated to bad prognosis and resistance against a number of different anticancer drugs. To selectively target these cells and to overcome this resistance we previously have developed prodrugs that are derivatives of existing anticancer drugs (e.g., doxorubicin) incorporating a sulfonamide moiety. When cleaved by GSTs, the prodrug releases the cytostatic moiety predominantly in GST overexpressing cells, thus sparing normal cells with moderate enzyme levels. By modifying the sulfonamide it is possible to control the rate of drug release and specifically target different GSTs. Here we show that the newly synthesized compounds, 4-acetyl-2-nitro-benzenesulfonyl etoposide (ANS-etoposide) and 4-acetyl-2-nitro-benzenesulfonyl doxorubicin (ANS-DOX), function as prodrugs for GSTA1 and MGST1 overexpressing cell lines. ANS-DOX, in particular, showed a desirable cytotoxic profile by inducing toxicity and DNA damage in a GST-dependent manner compared to control cells. Its moderate conversion of 500 nmol/min/mg, as catalyzed by GSTA1, seems hereby essential since the more reactive 2,4-dinitrobenzenesulfonyl doxorubicin (DNS-DOX) (14000 nmol/min/mg) did not display a preference for GSTA1 overexpressing cells. DNS-DOX, however, effectively killed GSTP1 (20 nmol/min/mg) and MGST1 (450 nmol/min/mg) overexpressing cells as did the less reactive 4-mononitrobenzenesulfonyl doxorubicin (MNS-DOX) in a MGST1-dependent manner (1.5 nmol/min/mg) as shown previously. Furthermore, we show that the mechanism of these prodrugs involves a reduction in GSH levels as well as inhibition of the redox regulatory enzyme thioredoxin reductase 1 (TrxR1) by virtue of their electrophilic sulfonamide moiety. TrxR1 is upregulated in many tumors and associated with resistance to chemotherapy and poor patient prognosis. Additionally, the prodrugs potentially acted as a general shuttle system for DOX, by overcoming resistance

  12. Interfacing protein lysine acetylation and protein phosphorylation

    PubMed Central

    Tran, Hue T.; Uhrig, R. Glen; Nimick, Mhairi; Moorhead, Greg B.

    2012-01-01

    Recognition that different protein covalent modifications can operate in concert to regulate a single protein has forced us to re-think the relationship between amino acid side chain modifications and protein function. Results presented by Tran et al. 2012 demonstrate the association of a protein phosphatase (PP2A) with a histone/lysine deacetylase (HDA14) on plant microtubules along with a histone/lysine acetyltransferase (ELP3). This finding reveals a regulatory interface between two prevalent covalent protein modifications, protein phosphorylation and acetylation, emphasizing the integrated complexity of post-translational protein regulation found in nature. PMID:22827947

  13. Determination of amphetamine by HPLC after acetylation.

    PubMed

    Veress, T

    2000-01-01

    An analytical procedure has been developed for the HPLC determination of amphetamine by off-line pre-column derivatization. The proposed procedure consists of sample preparation by acetylation of amphetamine with acetic anhydride and a subsequent reversed-phase HPLC separation on an octadecyl silica stationary phase with salt-free mobile phase (tetrahydrofuran, acetonitrile, 0.1% triethylamine in water, 15:15:70 v/v) applying UV-detection. The applicability of the elaborated procedure is demonstrated with results obtained by analysis of real samples seized in the Hungarian black market. PMID:10641931

  14. Lipase-catalyzed synthesis of acetylated EGCG and antioxidant properties of the acetylated derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    (-)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives were prepared by lipase catalyzed acylation of EGCG with vinyl acetate to improve its lipophilicity and expand its application in lipophilic media. The immobilized lipase, Lipozyme RM IM, was found to be the optimum catalyst. The optimiz...

  15. Structure, morphology and functionality of acetylated and oxidised barley starches.

    PubMed

    El Halal, Shanise Lisie Mello; Colussi, Rosana; Pinto, Vânia Zanella; Bartz, Josiane; Radunz, Marjana; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2015-02-01

    Acetylation and oxidation are chemical modifications which alter the properties of starch. The degree of modification of acetylated and oxidized starches is dependent on the catalyst and active chlorine concentrations, respectively. The objective of this study was to evaluate the effect of acetylation and oxidation on the structural, morphological, physical-chemical, thermal and pasting properties of barley starch. Barley starches were acetylated at different catalyst levels (11%, 17%, and 23% of NaOH solution) and oxidized at different sodium hypochlorite concentrations (1.0%, 1.5%, and 2.0% of active chlorine). Fourier-transformed infrared spectroscopy (FTIR), X-ray diffractograms, thermal, morphological, and pasting properties, swelling power and solubility of starches were evaluated. The degree of substitution (DS) of the acetylated starches increased with the rise in catalyst concentration. The percentage of carbonyl (CO) and carboxyl (COOH) groups in oxidized starches also increased with the rise of active chlorine level. The presence of hydrophobic acetyl groups, carbonyl and carboxyl groups caused a partial disorganization and depolymerization of starch granules. The structural, morphological and functional changes in acetylated and oxidized starches varied according to reaction conditions. Acetylation makes barley starch more hydrophobic by the insertion of acetyl groups. Also the oxidation promotes low retrogradation and viscosity. All these characteristics are important for biodegradable film production. PMID:25172707

  16. Protein lysine acetylation in bacteria: Current state of the art.

    PubMed

    Ouidir, Tassadit; Kentache, Takfarinas; Hardouin, Julie

    2016-01-01

    Post-translational modifications of proteins are key events in cellular metabolism and physiology regulation. Lysine acetylation is one of the best studied protein modifications in eukaryotes, but, until recently, ignored in bacteria. However, proteomic advances have highlighted the diversity of bacterial lysine-acetylated proteins. The current data support the implication of lysine acetylation in various metabolic pathways, adaptation and virulence. In this review, we present a broad overview of the current knowledge of lysine acetylation in bacteria. We emphasize particularly the significant contribution of proteomics in this field. PMID:26390373

  17. Determination of Acetylation of the Gli Transcription Factors.

    PubMed

    Coni, Sonia; Di Magno, Laura; Canettieri, Gianluca

    2015-01-01

    The Gli transcription factors (Gli1, Gli2, and Gli3) are the final effectors of the Hedgehog (Hh) signaling and play a key role in development and cancer. The activity of the Gli proteins is finely regulated by covalent modifications, such as phosphorylation, ubiquitination, and acetylation. Both Gli1 and Gli2 are acetylated at a conserved lysine, and this modification causes the inhibition of their transcriptional activity. Thus, the acetylation status of these proteins represents a useful marker to monitor Hh activation in pathophysiological conditions. Herein we describe the techniques utilized to detect in vitro and intracellular acetylation of the Gli transcription factors. PMID:26179046

  18. Probing the acetylation code of histone H4.

    PubMed

    Lang, Diana; Schümann, Michael; Gelato, Kathy; Fischle, Wolfgang; Schwarzer, Dirk; Krause, Eberhard

    2013-10-01

    Histone modifications play crucial roles in genome regulation with lysine acetylation being implicated in transcriptional control. Here we report a proteome-wide investigation of the acetylation-dependent protein-protein interactions of the N-terminal tail of histone H4. Quantitative peptide-based affinity MS experiments using the SILAC approach determined the interactomes of H4 tails monoacetylated at the four known acetylation sites K5, K8, K12, and K16, bis-acetylated at K5/K12, triple-acetylated at K8/12/16 and fully tetra-acetylated. A set of 29 proteins was found enriched on the fully acetylated H4 tail while specific binders of the mono and bis-acetylated tails were barely detectable. These observations are in good agreement with earlier reports indicating that the H4 acetylation state establishes its regulatory effects in a cumulative manner rather than via site-specific recruitment of regulatory proteins. PMID:23970329

  19. Generation of acetyllysine antibodies and affinity enrichment of acetylated peptides

    PubMed Central

    Guan, Kun-Liang; Yu, Wei; Lin, Yan; Xiong, Yue; Zhao, Shimin

    2016-01-01

    Lysine acetylation has emerged as one of the major post-translational modifications, as indicated by its roles in chromatin remodeling, activation of transcription factors and, most recently, regulation of metabolic enzymes. Identification of acetylation sites in a protein is the first essential step for functional characterization of acetylation in physiological regulation. However, the study of the acetylome is hindered by the lack of suitable physical and biochemical properties of the acetyl group and existence of high-abundance acetylated histones in the cell, and needs a robust method to overcome these problems. Here we present protocols for (i) using chemically acetylated ovalbumin and synthetic acetylated peptide to generate a pan-acetyllysine antibody and a site-specific antibody to Lys288-acetylated argininosuccinate lyase, respectively; (ii) using subcellular fractionation to reduce highly abundant acetylated histones; and (iii) using acetyllysine antibody affinity purification and mass spectrometry to characterize acetylome of human liver tissue. The entire characterization procedure takes ~2–3 d to complete. PMID:21085124

  20. Aldehyde-alcohol dehydrogenase and/or thiolase overexpression coupled with CoA transferase downregulation lead to higher alcohol titers and selectivity in Clostridium acetobutylicum fermentations.

    PubMed

    Sillers, Ryan; Al-Hinai, Mohab Ali; Papoutsakis, Eleftherios T

    2009-01-01

    Metabolic engineering (ME) of Clostridium acetobutylicum has led to increased solvent (butanol, acetone, and ethanol) production and solvent tolerance, thus demonstrating that further efforts have the potential to create strains of industrial importance. With recently developed ME tools, it is now possible to combine genetic modifications and thus implement more advanced ME strategies. We have previously shown that antisense RNA (asRNA)-based downregulation of CoA transferase (CoAT, the first enzyme in the acetone-formation pathway) results in increased butanol to acetone selectivity, but overall reduced butanol yields and titers. In this study the alcohol/aldehyde dehydrogenase (aad) gene (encoding the bifunctional protein AAD responsible for butanol and ethanol production from butyryl-CoA and acetyl-CoA, respectively) was expressed from the phosphotransbutyrylase (ptb) promoter to enhance butanol formation and selectivity, while CoAT downregulation was used to minimize acetone production. This led to early production of high alcohol (butanol plus ethanol) titers, overall solvent titers of 30 g/L, and a higher alcohol/acetone ratio. Metabolic flux analysis revealed the likely depletion of butyryl-CoA. In order to increase then the flux towards butyryl-CoA, we examined the impact of thiolase (THL, thl) overexpression. THL converts acetyl-CoA to acetoacetyl-CoA, the first step of the pathway from acetyl-CoA to butyryl-CoA, and thus, combining thl overexpression with aad overexpression decreased, as expected, acetate and ethanol production while increasing acetone and butyrate formation. thl overexpression in strains with asRNA CoAT downregulation did not significantly alter product formation thus suggesting that a more complex metabolic engineering strategy is necessary to enhance the intracellular butyryl-CoA pool and reduce the acetyl-CoA pool in order to achieve improved butanol titers and selectivity. PMID:18726959

  1. Developmental aspects of glutathione S-transferase B (ligandin) in rat liver.

    PubMed Central

    Hales, B F; Neims, A H

    1976-01-01

    The postnatal development in male Sprague-Dawley rats of hepatic glutathione S-transferase B (ligandin) in relation to the other glutathione S-transferases is described. The concentration of glutathione S-transferase B in 1-day-old male rats is about one-fifth of that in adult animals. The enzyme reaches adult concentrations 4-5 weeks later. When assessed by substrate specificity or immunologically, the proportion of transferase B relative to the other glutathione S-transferases is high during the first week after birth. At this age, 67.5% of the transferase activity towards 1-chloro-2,4-dinitrobenzene is immunoprecipitable by anti-(transferase B), compared with about 50% in adults and older pups. Between the second and the fifth postnatal week, the fraction of transferase B increases in parallel fashion with the other transferases in hepatic cytosol. Neither L-thyroxine nor cortisol induce a precocious increase in glutathione S-transferase activity. Phenobarbital did induce transferase activity towards 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene in both pups and adults. The extent of induction by phenobarbital was a function of basal activity during development such that the percentage stimulation remained constant from 5 days postnatally to adulthood. PMID:1008852

  2. Purification and characterization of a DNA strand transferase from broccoli.

    PubMed

    Tissier, A F; Lopez, M F; Signer, E R

    1995-05-01

    A protein with DNA binding, renaturation, and strand-transfer activities has been purified to homogeneity from broccoli (Brassica oleracea var italica). The enzyme, broccoli DNA strand transferase, has a native molecular mass of at least 200 kD and an apparent subunit molecular mass of 95 kD and is isolated as a set of isoforms differing only in charge. All three activities are saturated at very low stoichiometry, one monomer per approximately 1000 nucleotides of single-stranded DNA. Strand transfer is not effected by nuclease activity and reannealing, is only slightly dependent on ATP, and is independent of added Mg2+. Transfer requires homologous single- and double-stranded DNA and at higher enzyme concentrations results in very high molecular mass complexes. As with Escherichia coli RecA, transfer by broccoli DNA strand transferase depends strongly on the presence of 3' homologous ends. PMID:7784508

  3. The Fasted/Fed Mouse Metabolic Acetylome: N6-Acetylation Differences Suggest Acetylation Coordinates Organ-Specific Fuel Switching

    PubMed Central

    Yang, Li; Vaitheesvaran, Bhavapriya; Hartil, Kirsten; Robinson, Alan J.; Hoopmann, Michael R.; Eng, Jimmy K.; Kurland, Irwin J.; Bruce, James E.

    2011-01-01

    The elucidation of extra-nuclear lysine acetylation has been of growing interest, as the co-substrate for acetylation, acetyl CoA, is at a key metabolic intersection. Our hypothesis was that mitochondrial and cytoplasmic protein acetylation may be part of a fasted/re-fed feedback control system for the regulation of the metabolic network in fuel switching, where acetyl CoA would be provided by fatty acid oxidation, or glycolysis, respectively. To test this we characterized the mitochondrial and cytoplasmic acetylome in various organs that have a high metabolic rate relative to their mass, and/or switch fuels, under fasted and re-fed conditions (brain, kidney, liver, skeletal muscle, heart muscle, white and brown adipose tissues). Using immunoprecipitation, coupled with LC-MSMS label free quantification, we show there is a dramatic variation in global quantitative profiles of acetylated proteins from different organs. In total, 733 acetylated peptides from 337 proteins were identified and quantified, out of which 31 acetylated peptides from the metabolic proteins that may play organ-specific roles were analyzed in detail. Results suggest that fasted/re-fed acetylation changes coordinated by organ-specific (de-)acetylases in insulin-sensitive versus insensitive organs may underlie fuel use and switching. Characterization of the tissue-specific acetylome should increase understanding of metabolic conditions wherein normal fuel switching is disrupted, such as in Type II diabetes. PMID:21728379

  4. N-acetylaspartate catabolism determines cytosolic acetyl-CoA levels and histone acetylation in brown adipocytes

    PubMed Central

    Prokesch, A.; Pelzmann, H. J.; Pessentheiner, A. R.; Huber, K.; Madreiter-Sokolowski, C. T.; Drougard, A.; Schittmayer, M.; Kolb, D.; Magnes, C.; Trausinger, G.; Graier, W. F.; Birner-Gruenberger, R.; Pospisilik, J. A.; Bogner-Strauss, J. G.

    2016-01-01

    Histone acetylation depends on the abundance of nucleo-cytoplasmic acetyl-CoA. Here, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. N-acetylaspartate (NAA) is a highly abundant brain metabolite catabolized by aspartoacylase yielding aspartate and acetate. The latter can be further used for acetyl-CoA production. Prior to this work, the presence of NAA has not been described in adipocytes. Here, we show that accumulation of NAA decreases the brown adipocyte phenotype. We increased intracellular NAA concentrations in brown adipocytes via media supplementation or knock-down of aspartoacylase and measured reduced lipolysis, thermogenic gene expression, and oxygen consumption. Combinations of approaches to increase intracellular NAA levels showed additive effects on lipolysis and gene repression, nearly abolishing the expression of Ucp1, Cidea, Prdm16, and Ppara. Transcriptome analyses of aspartoacylase knock-down cells indicate deficiencies in acetyl-CoA and lipid metabolism. Concordantly, cytoplasmic acetyl-CoA levels and global histone H3 acetylation were decreased. Further, activating histone marks (H3K27ac and H3K9ac) in promoters/enhancers of brown marker genes showed reduced acetylation status. Taken together, we present a novel route for cytoplasmic acetyl-CoA production in brown adipocytes. Thereby, we mechanistically connect the NAA pathway to the epigenomic regulation of gene expression, modulating the phenotype of brown adipocytes. PMID:27045997

  5. Physical mapping in the Cri du Chat region on human chromosome 5

    SciTech Connect

    Church, D.M.; Bengtsson, U.; Niebuhr, E.

    1994-09-01

    The Cri du Chat syndrome is a segmental aneusomy associated with deletions in the short arm of human chromosome 5. More specifically, the cytogenetic band 5p15.2 must be deleted in order to manifest the typical phenotypic signs. We have studied several cell lines from individuals who have chromosomal abnormalities within this cytogenetic band but who do not have typical Cri du Chat syndrome. In fact, several individual studied have no discernible features of this syndrome. Using fluorescent in situ hybridization (FISH) analysis and PCR analysis on somatic cell hybrids we have mapped the breakpoints relative to each other within this band. There is a great degree of phenotypic heterogeneity between several of the patients, even those which share common breakpoints. This heterogeneity makes it very difficult to narrow the region of interest to a very small (<1 Mb) region. In order to more thoroughly analyze this region, we have assembled a yeast artificial chromosome (YAC) contig of part of this region. This contig has been analyzed for STS content and covers approximately a 1.5-2.0 Mb region within 5p15.2. In addition, we have constructed a radiation hybrid map of the region. The YACs contained within the minimal contig have been used as hybridization probes to isolate corresponding cosmid clones within the region of interest. These cosmids, in turn, are being utilized to obtain potential exons using exon amplification. Several cosmids within this region have been isolated by STS content and potential exons have been isolated from them. These exons have been used as probes to isolate cDNA clones from the region. It is our hope that isolation of genes throughout the region of interest will allow a better understanding of the etiology of Cri du Chat.

  6. Real-time reference: the use of chat technology to improve point of need assistance.

    PubMed

    Connor, Elizabeth

    2002-01-01

    Chat reference refers to the use of instant messaging and call center software to support interactive text or voice communication with library patrons. Instant messaging has been integrated into many e-commerce environments, and into the social lives of many teenagers and young adults, affording a level of immediacy and intimacy not possible with e-mail applications. The convergence and interoperability of new and emerging technologies can be used to develop new communities of users that view libraries as being essential to their education, patient care, and research activities. PMID:12659452

  7. IRC on your dime? What you really need to know about Internet relay chat

    SciTech Connect

    ERayome, J.; Romig, S., LLNL

    1998-05-22

    The purpose of this paper is to describe recent trends CIAC has encountered while working with sites that have been compromised. Frequently, the intruders set up and run Internet Relay Chat (IRC) to exchange information and to show off their success at having compromised a site. Invariably, this protocol consumes bandwidth, uses CPU cycles and is a source of embarrassment for the site. This paper focuses on these negative aspects of IRC and concedes that one can cite numerous examples where IRC is used in a positive manner.

  8. Thermochemical characteristics of cellulose acetates with different degrees of acetylation

    NASA Astrophysics Data System (ADS)

    Larina, V. N.; Ur'yash, V. F.; Kushch, D. S.

    2012-12-01

    The standard enthalpies of combustion and formation of cellulose acetates with different degrees of acetylation are determined. It is established that there is a proportional dependence of these thermochemical characteristics vs. the degree of acetylation, weight fraction of bonded acetic acid, and molar mass of the repeating unit of cellulose acetates.

  9. Emerging Functions for N-Terminal Protein Acetylation in Plants.

    PubMed

    Gibbs, Daniel J

    2015-10-01

    N-terminal (Nt-) acetylation is a widespread but poorly understood co-translational protein modification. Two reports now shed light onto the proteome-wide dynamics and protein-specific consequences of Nt-acetylation in relation to plant development, stress-response, and protein stability, identifying this modification as a key regulator of diverse aspects of plant growth and behaviour. PMID:26319188

  10. Effect of acetaminophen on sulfamethazine acetylation in male volunteers.

    PubMed

    Tahir, I M; Iqbal, T; Saleem, S; Mehboob, H; Akhter, N; Riaz, M

    2016-03-01

    The effect of acetaminophen on sulfamethazine N-acetylation by human N-acetyltrasferase-2 (NAT2) was studied in 19 (n=19) healthy male volunteers in two different phases. In the first phase of the study the volunteers were given an oral dose of sulfamethazine 500 mg alone and blood and urine samples were collected. After the 10-day washout period the same selected volunteers were again administered sulfamethazine 500 mg along with 1000 mg acetaminophen. The acetylation of sulfamethazine by human NAT2 in both phases with and without acetaminophen was determined by HPLC to establish their respective phenotypes. In conclusion obtained statistics of present study revealed that acetaminophen significantly (P<0.0001) decreased sulfamethazine acetylation in plasma of both slow and fast acetylator male volunteers. A highly significant (P<0.0001) decrease in plasma-free and total sulfamethazine concentration was also observed when acetaminophen was co-administered. Urine acetylation status in both phases of the study was found not to be in complete concordance with that of plasma. Acetaminophen significantly (P<0.0001) increased the acetyl, free and total sulfamethazine concentration in urine of both slow and fast acetylators. Urine acetylation analysis has not been found to be a suitable approach for phenotypic studies. PMID:26519524

  11. An Alternative Strategy for Pan-acetyl-lysine Antibody Generation.

    PubMed

    Kim, Sun-Yee; Sim, Choon Kiat; Zhang, Qiongyi; Tang, Hui; Brunmeir, Reinhard; Pan, Hong; Karnani, Neerja; Han, Weiping; Zhang, Kangling; Xu, Feng

    2016-01-01

    Lysine acetylation is an important post-translational modification in cell signaling. In acetylome studies, a high-quality pan-acetyl-lysine antibody is key to successful enrichment of acetylated peptides for subsequent mass spectrometry analysis. Here we show an alternative method to generate polyclonal pan-acetyl-lysine antibodies using a synthesized random library of acetylated peptides as the antigen. Our antibodies are tested to be specific for acetyl-lysine peptides/proteins via ELISA and dot blot. When pooled, five of our antibodies show broad reactivity to acetyl-lysine peptides, complementing a commercial antibody in terms of peptide coverage. The consensus sequence of peptides bound by our antibody cocktail differs slightly from that of the commercial antibody. Lastly, our antibodies are tested in a proof-of-concept to analyze the acetylome of HEK293 cells. In total we identified 1557 acetylated peptides from 416 proteins. We thus demonstrated that our antibodies are well-qualified for acetylome studies and can complement existing commercial antibodies. PMID:27606599

  12. Medial temporal N-acetyl aspartate in pediatric major depression

    PubMed Central

    MacMaster, Frank P.; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S. Preeya; Buhagiar, Christian; Rosenberg, David R.

    2008-01-01

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD-case control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  13. Medial temporal N-acetyl-aspartate in pediatric major depression.

    PubMed

    MacMaster, Frank P; Moore, Gregory J; Russell, Aileen; Mirza, Yousha; Taormina, S Preeya; Buhagiar, Christian; Rosenberg, David R

    2008-10-30

    The medial temporal cortex (MTC) has been implicated in the pathogenesis of pediatric major depressive disorder (MDD). Eleven MDD case-control pairs underwent proton magnetic resonance spectroscopic imaging. N-acetyl-aspartate was lower in the left MTC (27%) in MDD patients versus controls. Lower N-acetyl-aspartate concentrations in MDD patients may reflect reduced neuronal viability. PMID:18703320

  14. Global analysis of lysine acetylation in strawberry leaves

    PubMed Central

    Fang, Xianping; Chen, Wenyue; Zhao, Yun; Ruan, Songlin; Zhang, Hengmu; Yan, Chengqi; Jin, Liang; Cao, Lingling; Zhu, Jun; Ma, Huasheng; Cheng, Zhongyi

    2015-01-01

    Protein lysine acetylation is a reversible and dynamic post-translational modification. It plays an important role in regulating diverse cellular processes including chromatin dynamic, metabolic pathways, and transcription in both prokaryotes and eukaryotes. Although studies of lysine acetylome in plants have been reported, the throughput was not high enough, hindering the deep understanding of lysine acetylation in plant physiology and pathology. In this study, taking advantages of anti-acetyllysine-based enrichment and high-sensitive-mass spectrometer, we applied an integrated proteomic approach to comprehensively investigate lysine acetylome in strawberry. In total, we identified 1392 acetylation sites in 684 proteins, representing the largest dataset of acetylome in plants to date. To reveal the functional impacts of lysine acetylation in strawberry, intensive bioinformatic analysis was performed. The results significantly expanded our current understanding of plant acetylome and demonstrated that lysine acetylation is involved in multiple cellular metabolism and cellular processes. More interestingly, nearly 50% of all acetylated proteins identified in this work were localized in chloroplast and the vital role of lysine acetylation in photosynthesis was also revealed. Taken together, this study not only established the most extensive lysine acetylome in plants to date, but also systematically suggests the significant and unique roles of lysine acetylation in plants. PMID:26442052

  15. Determination of Activity of the Enzymes Hypoxanthine Phosphoribosyl Transferase (HPRT) and Adenine Phosphoribosyl Transferase (APRT) in Blood Spots on Filter Paper.

    PubMed

    Auler, Kasie; Broock, Robyn; Nyhan, William L

    2015-01-01

    Hypoxanthine-guanine phosphoribosyl-transferase (HPRT) deficiency is the cause of Lesch-Nyhan disease. Adenine phosphoribosyl-transferase (APRT) deficiency causes renal calculi. The activity of each enzyme is readily determined on spots of whole blood on filter paper. This unit describes a method for detecting deficiencies of HPRT and APRT. PMID:26132002

  16. Disembodiment in online social interaction: impact of online chat on social support and psychosocial well-being.

    PubMed

    Kang, Seok

    2007-06-01

    This study investigates how disembodiment--that is, transcendence of body constraints in cyberspace--in online chat affects social psychological well-being. The results demonstrate that disembodiment is a strong predictor of increased loneliness and depression, and decreased social support. However, the amount of chat use is a positive contributor to decreased offline estrangement and depression, and increased happiness. These contrasting results suggest that online chat use is a technology for social connection used for offline connectivity, but the disembodiment motive is associated with declines in social support and psychosocial well-being. The investigation of specified motives for online interaction, personal competency, or advanced technological alternatives in interaction is suggested for future research on the effects of online interaction on offline outcomes. PMID:17594274

  17. Inclinometer monitoring system for stability analysis: the western slope of the Bełchatów field case study

    NASA Astrophysics Data System (ADS)

    Cała, Marek; Jakóbczyk, Joanna; Cyran, Katarzyna

    2016-06-01

    The geological structure of the Bełchatów area is very complicated as a result of tectonic and sedimentation processes. The long-term exploitation of the Bełchatów field influenced the development of horizontal displacements. The variety of factors that have impact on the Bełchatów western slope stability conditions, forced the necessity of complex geotechnical monitoring. The geotechnical monitoring of the western slope was carried out with the use of slope inclinometers. From 2005 to 2013 fourteen slope inclinometers were installed, however, currently seven of them are in operation. The present analysis depicts inclinometers situated in the north part of the western slope, for which the largest deformations were registered. The results revealed that the horizontal displacements and formation of slip surfaces are related to complicated geological structure and intensive tectonic deformations in the area. Therefore, the influence of exploitation marked by changes in slope geometry was also noticeable.

  18. Variable Omission of "ne" in Real-Time French Chat: A Corpus-Driven Comparison of Educational and Non-Educational Contexts

    ERIC Educational Resources Information Center

    van Compernolle, Remi A.; Williams, Lawrence

    2009-01-01

    This article reports on the variable omission of the French negative particle "ne" (the first marker of verbal negation) in synchronous (i.e., real-time) electronic communication environments. Patterns of variation in a corpus of non-educational chat (i.e., free, public-access Internet chat) are analyzed and compared to data produced by first-,…

  19. Frequency and Content of Chat Questions by Time of Semester at the University of Central Florida: Implications for Training, Staffing and Marketing

    ERIC Educational Resources Information Center

    Goda, Donna; Bishop, Corinne

    2008-01-01

    The more than 4,000 "chats" received by the University of Central Florida's (UCF) Ask-A-Librarian digital reference service are the subject of this practitioner-based, descriptive case study. Question content from chats received during four semesters between January 2005 and May 2006 are categorized and plotted, by semester, to show the number of…

  20. Developmental Chronology of Preverbal Social Behaviors in Infancy Using the M-CHAT: Baseline for Early Detection of Atypical Social Development

    ERIC Educational Resources Information Center

    Inada, Naoko; Kamio, Yoko; Koyama, Tomonori

    2010-01-01

    This study aimed to identify the age of emergence and subsequent order of preverbal social behaviors, which have not yet been fully clarified. This was accomplished using 16 items of social behaviors extracted from the Modified Checklist for Toddlers with Autism (M-CHAT). The Japanese version of the M-CHAT was completed voluntarily by the parents…

  1. Modified Checklist for Autism in Toddlers (M-CHAT) Screening at 18 Months of Age Predicts Concurrent Understanding of Desires, Word Learning and Expressive Vocabulary

    ERIC Educational Resources Information Center

    Wright, Kristyn; Poulin-Dubois, Diane

    2012-01-01

    The Modified Checklist for Autism in Toddlers (M-CHAT) is a 23-item questionnaire used in primary screening of Autism Spectrum Disorder (ASD). The current studies examine the concurrent validity of the M-CHAT in its ability to predict 18-month-olds' performance on theory of mind and word learning tasks. In Experiment 1, infants' understanding of…

  2. Reflections on CHAT and Freire's Participatory Action Research from the West of Scotland: "Praxis," Politics, and the "Struggle for Meaningful Life"

    ERIC Educational Resources Information Center

    Collins, Chik

    2011-01-01

    This article offers a perspective on the relationship between cultural-historical activity theory (CHAT) and one particular strand of action research--Freirean participatory action research (PAR). It reflects on a research collaboration conducted two decades ago with a community organisation and seeks to "show" the interaction of CHAT and Freirean…

  3. Antemortem stress regulates protein acetylation and glycolysis in postmortem muscle.

    PubMed

    Li, Zhongwen; Li, Xin; Wang, Zhenyu; Shen, Qingwu W; Zhang, Dequan

    2016-07-01

    Although exhaustive research has established that preslaughter stress is a major factor contributing to pale, soft, exudative (PSE) meat, questions remain regarding the biochemistry of postmortem glycolysis. In this study, the influence of preslaughter stress on protein acetylation in relationship to glycolysis was studied. The data show that antemortem swimming significantly enhanced glycolysis and the total acetylated proteins in postmortem longissimus dorsi (LD) muscle of mice. Inhibition of protein acetylation by histone acetyltransferase (HAT) inhibitors eliminated stress induced increase in glycolysis. Inversely, antemortem injection of histone deacetylase (HDAC) inhibitors, trichostatin A (TSA) and nicotinamide (NAM), further increased protein acetylation early postmortem and the glycolysis. These data provide new insight into the biochemistry of postmortem glycolysis by showing that protein acetylation regulates glycolysis, which may participate in the regulation of preslaughter stress on glycolysis in postmortem muscle. PMID:26920270

  4. Acetylated histone H3 increases nucleosome dissociation

    NASA Astrophysics Data System (ADS)

    Simon, Marek; Manohar, Mridula; Ottesen, Jennifer; Poirier, Michael

    2009-03-01

    Chromatin's basic unit structure is the nucleosome, i.e. genomic DNA wrapped around a particular class of proteins -- histones -- which due to their physical hindrance, block vital biological processes, such as DNA repair, DNA replication, and RNA transcription. Histone post-translational modifications, which are known to exist in vivo, are hypothesized to regulate these biological processes by directly altering DNA-histone interactions and thus nucleosome structure and stability. Using magnetic tweezers technique we studied the acetylation of histone H3 in the dyad region, i.e. at K115 and K122, on reconstituted arrays of nucleosomes under constant external force. Based on the measured increase in the probability of dissociation of modified nucleosomes, we infer that this double modification could facilitate histone chaperone mediated nucleosome disassembly in vivo.

  5. "De-humanised females and Amazonians": British wartime fashion and its representation in Home chat, 1914-1918.

    PubMed

    Buckley, Cheryl

    2002-01-01

    Popular representations of the fashionably dressed female body between 1914 and 1918 were highly contradictory and, as this essay will show, were sharply delineated in Home Chat, one of a growing number of relatively new women's magazines which addressed the needs of an expanding skilled working-class and lower-middle-class female readership. Aiming to provide women with practical advice about all aspects of their daily lives, from the traditional concerns of fashion and beauty, marriage and children, to the more contentious issue of women's aspirations beyond the home, Home Chat was uniquely placed to reflect shifting gender and class relations. PMID:17484102

  6. Automatic Association of Chats and Video Tracks for Activity Learning and Recognition in Aerial Video Surveillance

    PubMed Central

    Hammoud, Riad I.; Sahin, Cem S.; Blasch, Erik P.; Rhodes, Bradley J.; Wang, Tao

    2014-01-01

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports. PMID:25340453

  7. Automatic association of chats and video tracks for activity learning and recognition in aerial video surveillance.

    PubMed

    Hammoud, Riad I; Sahin, Cem S; Blasch, Erik P; Rhodes, Bradley J; Wang, Tao

    2014-01-01

    We describe two advanced video analysis techniques, including video-indexed by voice annotations (VIVA) and multi-media indexing and explorer (MINER). VIVA utilizes analyst call-outs (ACOs) in the form of chat messages (voice-to-text) to associate labels with video target tracks, to designate spatial-temporal activity boundaries and to augment video tracking in challenging scenarios. Challenging scenarios include low-resolution sensors, moving targets and target trajectories obscured by natural and man-made clutter. MINER includes: (1) a fusion of graphical track and text data using probabilistic methods; (2) an activity pattern learning framework to support querying an index of activities of interest (AOIs) and targets of interest (TOIs) by movement type and geolocation; and (3) a user interface to support streaming multi-intelligence data processing. We also present an activity pattern learning framework that uses the multi-source associated data as training to index a large archive of full-motion videos (FMV). VIVA and MINER examples are demonstrated for wide aerial/overhead imagery over common data sets affording an improvement in tracking from video data alone, leading to 84% detection with modest misdetection/false alarm results due to the complexity of the scenario. The novel use of ACOs and chat Sensors 2014, 14 19844 messages in video tracking paves the way for user interaction, correction and preparation of situation awareness reports. PMID:25340453

  8. Characterization of O-Acetylation of N-Acetylglucosamine

    PubMed Central

    Bernard, Elvis; Rolain, Thomas; Courtin, Pascal; Guillot, Alain; Langella, Philippe; Hols, Pascal; Chapot-Chartier, Marie-Pierre

    2011-01-01

    Peptidoglycan (PG) N-acetyl muramic acid (MurNAc) O-acetylation is widely spread in Gram-positive bacteria and is generally associated with resistance against lysozyme and endogenous autolysins. We report here the presence of O-acetylation on N-acetylglucosamine (GlcNAc) in Lactobacillus plantarum PG. This modification of glycan strands was never described in bacteria. Fine structural characterization of acetylated muropeptides released from L. plantarum PG demonstrated that both MurNAc and GlcNAc are O-acetylated in this species. These two PG post-modifications rely on two dedicated O-acetyltransferase encoding genes, named oatA and oatB, respectively. By analyzing the resistance to cell wall hydrolysis of mutant strains, we showed that GlcNAc O-acetylation inhibits N-acetylglucosaminidase Acm2, the major L. plantarum autolysin. In this bacterial species, inactivation of oatA, encoding MurNAc O-acetyltransferase, resulted in marked sensitivity to lysozyme. Moreover, MurNAc over-O-acetylation was shown to activate autolysis through the putative N-acetylmuramoyl-l-alanine amidase LytH enzyme. Our data indicate that in L. plantarum, two different O-acetyltransferases play original and antagonistic roles in the modulation of the activity of endogenous autolysins. PMID:21586574

  9. Chitosan Molecular Structure as a Function of N-Acetylation

    SciTech Connect

    Franca, Eduardo F.; Freitas, Luiz C.; Lins, Roberto D.

    2011-07-01

    Molecular dynamics simulations have been carried out to characterize the structure and solubility of chitosan nanoparticle-like structures as a function of the deacetylation level (0, 40, 60, and 100%) and the spatial distribution of the N-acetyl groups in the particles. The polysaccharide chains of highly N-deacetylated particles where the N-acetyl groups are uniformly distributed present a high flexibility and preference for the relaxed two-fold helix and five-fold helix motifs. When these groups are confined to a given region of the particle, the chains adopt preferentially a two-fold helix with f and w values close to crystalline chitin. Nanoparticles with up to 40% acetylation are moderately soluble, forming stable aggregates when the N-acetyl groups are unevenly distributed. Systems with 60% or higher N-acetylation levels are insoluble and present similar degrees of swelling regardless the distribution of their N-acetyl groups. Overall particle solvation is highly affected by electrostatic forces resulting from the degree of acetylation. The water mobility and orientation around the polysaccharide chains affects the stability of the intramolecular O3- HO3(n) ... O5(n+ 1) hydrogen bond, which in turn controls particle aggregation.

  10. Role of Histone Acetylation in Cell Cycle Regulation.

    PubMed

    Koprinarova, Miglena; Schnekenburger, Michael; Diederich, Marc

    2016-01-01

    Core histone acetylation is a key prerequisite for chromatin decondensation and plays a pivotal role in regulation of chromatin structure, function and dynamics. The addition of acetyl groups disturbs histone/DNA interactions in the nucleosome and alters histone/histone interactions in the same or adjacent nucleosomes. Acetyl groups can also provide binding sites for recruitment of bromodomain (BRD)-containing non-histone readers and regulatory complexes to chromatin allowing them to perform distinct downstream functions. The presence of a particular acetylation pattern influences appearance of other histone modifications in the immediate vicinity forming the "histone code". Although the roles of the acetylation of particular lysine residues for the ongoing chromatin functions is largely studied, the epigenetic inheritance of histone acetylation is a debated issue. The dynamics of local or global histone acetylation is associated with fundamental cellular processes such as gene transcription, DNA replication, DNA repair or chromatin condensation. Therefore, it is an essential part of the epigenetic cell response to processes related to internal and external signals. PMID:26303420

  11. Crystal structure of farnesyl protein transferase complexed with a CaaX peptide and farnesyl diphosphate analogue.

    PubMed

    Strickland, C L; Windsor, W T; Syto, R; Wang, L; Bond, R; Wu, Z; Schwartz, J; Le, H V; Beese, L S; Weber, P C

    1998-11-24

    The crystallographic structure of acetyl-Cys-Val-Ile-selenoMet-COOH and alpha-hydroxyfarnesylphosphonic acid (alphaHFP) complexed with rat farnesyl protein transferase (FPT) (space group P61, a = b = 174. 13 A, c = 69.71 A, alpha = beta = 90 degrees, gamma = 120 degrees, Rfactor = 21.8%, Rfree = 29.2%, 2.5 A resolution) is reported. In the ternary complex, the bound substrates are within van der Waals contact of each other and the FPT enzyme. alphaHFP binds in an extended conformation in the active-site cavity where positively charged side chains and solvent molecules interact with the phosphate moiety and aromatic side chains pack adjacent to the isoprenoid chain. The backbone of the bound CaaX peptide adopts an extended conformation, and the side chains interact with both FPT and alphaHFP. The cysteine sulfur of the bound peptide coordinates the active-site zinc. Overall, peptide binding and recognition appear to be dominated by side-chain interactions. Comparison of the structures of the ternary complex and unliganded FPT [Park, H., Boduluri, S., Moomaw, J., Casey, P., and Beese, L. (1997) Science 275, 1800-1804] shows that major rearrangements of several active site side chains occur upon substrate binding. PMID:9843427

  12. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a)...

  13. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a)...

  14. Psychological Well-Being in Parents of Children with Angelman, Cornelia de Lange and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Griffith, G. M.; Hastings, R. P.; Oliver, C.; Howlin, P.; Moss, J.; Petty, J.; Tunnicliffe, P.

    2011-01-01

    Background: The current study focuses on mothers and fathers of children with three rare genetic syndromes that are relatively unexplored in terms of family experience: Angelman syndrome, Cornelia de Lange syndrome and Cri du Chat syndrome. Method: Parents of children with Angelman syndrome (n = 15), Cornelia de Lange syndrome (n = 16) and Cri du…

  15. A Description of Adaptive and Maladaptive Behaviour in Children and Adolescents with Cri-du-Chat Syndrome

    ERIC Educational Resources Information Center

    Teixeira, M. C. T. V.; Emerich, D. R.; Orsati, F. T.; Rimerio, R. C.; Gatto, K. R.; Chappaz, I. O.; Kim, C. A.

    2011-01-01

    Background: Psychological tests can be useful to record adaptive and maladaptive behaviours of children with intellectual disability. The objective of this study was to describe the adaptive and maladaptive behaviour of children and adolescents with Cri-du-chat syndrome. Methods: The sample consisted of 10 children and adolescents with Cri-du-chat…

  16. "O Que Diriam Sobre Os Portugueses?????" [What Would You Say about Portuguese People?]: Intercultural Curiosity in Multilingual Chat-Rooms

    ERIC Educational Resources Information Center

    Araujo e Sa, Maria Helena; de Carlo, Maddalena; Melo-Pfeifer, Silvia

    2010-01-01

    In this study, we intend to discuss questioning as a sign of Intercultural Communicative Competence in plurilingual environments, stressing the relationship between questioning and the process of developing discovery skills in Romance chat-rooms. Focusing specifically on episodes beginning with intercultural questioning, we will analyse: (1)…

  17. Looking from a CHAT-IT Perspective to Undergraduate Mexican Physics: Organizational Trajectories or Professors as Agents of Change?

    ERIC Educational Resources Information Center

    Kahveci, Ajda

    2010-01-01

    Recent elaborations on cultural-historical activity theory (CHAT) (Engestrom et al., eds., "Perspectives on activity theory." New York: Cambridge University Press, "1999") and its relation to organizational theories have produced a theoretical amalgam of these earlier ideas, which allow for the exploration of learning in formal organizational…

  18. Prisons and Primary Schools: Using CHAT to Analyse the Relationship between Developing Identity, Developing Musicianship and Transformative Processes

    ERIC Educational Resources Information Center

    Henley, Jennie

    2015-01-01

    This paper draws on three different research projects to demonstrate the use of an expanded model of Cultural Historical Activity Theory (CHAT), developed as part of a doctoral research study. The first project is an evaluation of the impacts of a Music Partnership Project within Primary and Secondary schools. The second project is an evaluation…

  19. Deutsch, Doyc or Doitsch? Chatters as Languagers--The Case of a German-Turkish Chat Room

    ERIC Educational Resources Information Center

    Hinnenkamp, Volker

    2008-01-01

    The paper looks at the process of online-languaging of adolescents with a migratory and ethnic Turkish background in a diasporic chat room. The multiple resources and voices used are analysed. One particular example is looked at more thoroughly to illustrate the process of languaging and how it is legitimised by the chatters themselves. Finally,…

  20. Reliability and Validity of the Japanese Version of the Modified Checklist for Autism in Toddlers (M-CHAT)

    ERIC Educational Resources Information Center

    Inada, Naoko; Koyama, Tomonori; Inokuchi, Eiko; Kuroda, Miho; Kamio, Yoko

    2011-01-01

    Early detection and intervention is essential for children with autism spectrum disorders (ASD). Therefore, we examined the reliability and validity of the Japanese version of the Modified Checklist for autism in toddlers (M-CHAT), a 23-item, yes-no questionnaire regarding early autistic symptoms completed by parents of children at 18-24 months of…

  1. Examination of the Properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in a Population Sample

    ERIC Educational Resources Information Center

    Yama, Brie; Freeman, Tom; Graves, Erin; Yuan, Su; Campbell, M. Karen

    2012-01-01

    This study examines the following properties of the Modified Checklist for Autism in Toddlers (M-CHAT) in an unselected low-risk sample: (a) the maximum age for screen administration; (b) the positive screen rate in the absence of follow-up telephone interviews and; (c) the distributional properties of positive screens. Data came from a…

  2. Voice vs. Text Chats: Their Efficacy for Learning Probing Questions by Non-Native Speaking Medical Professionals in Online Courses

    ERIC Educational Resources Information Center

    Ellis, Olga

    2012-01-01

    Through an English for Specific Purposes (ESP): Communication in Nursing online course, the present study examines the efficacy of synchronous voice-based and text-based chats as instructional and communicative modes in learning to use open questions for probing in therapeutic dialogues by non-native speaking (NNS) participants, students of a…

  3. Social Behavior and Characteristics of Autism Spectrum Disorder in Angelman, Cornelia de Lange, and Cri du Chat Syndromes

    ERIC Educational Resources Information Center

    Moss, Joanna; Howlin, Patricia; Hastings, Richard Patrick; Beaumont, Sarah; Griffith, Gemma M.; Petty, Jane; Tunnicliffe, Penny; Yates, Rachel; Villa, Darrelle; Oliver, Chris

    2013-01-01

    We evaluated autism spectrum disorder (ASD) characteristics and social behavior in Angelman (AS; "n" ?=? 19; mean age ?=?10.35 years), Cornelia de Lange (CdLS; "n" ?=? 15; mean age ?=?12.40 years), and Cri du Chat (CdCS, also known as 5 p-syndrome; "n" ?=? 19; mean age ?=? 8.80 years) syndromes. The proportion of…

  4. Evidence for N----O acetyl migration as the mechanism for O acetylation of peptidoglycan in Proteus mirabilis.

    PubMed Central

    Dupont, C; Clarke, A J

    1991-01-01

    O-acetylated peptidoglycan was purified from Proteus mirabilis grown in the presence of specifically radiolabelled glucosamine derivatives, and the migration of the radiolabel was monitored. Mild-base hydrolysis of the isolated peptidoglycan (to release ester-linked acetate) from cells grown in the presence of 40 microM [acetyl-3H]N-acetyl-D-glucosamine resulted in the release of [3H]acetate, as detected by high-pressure liquid chromatography. The inclusion of either acetate, pyruvate, or acetyl phosphate, each at 1 mM final concentration, did not result in a diminution of mild-base-released [3H]acetate levels. No such release of [3H]acetate was observed with peptidoglycan isolated from either Escherichia coli incubated with the same radiolabel or P. mirabilis grown with [1,6-3H]N-acetyl-D-glucosamine or D-[1-14C]glucosamine. These observations support a hypothesis that O acetylation occurs by N----O acetyl transfer within the sacculus. A decrease in [3H]acetate release by mild-base hydrolysis was observed with the peptidoglycan of P. mirabilis cultures incubated in the presence of antagonists of peptidoglycan biosynthesis, penicillin G and D-cycloserine. The absence of free-amino sugars in the peptidoglycan of P. mirabilis but the detection of glucosamine in spent culture broths implies that N----O transacetylation is intimately associated with peptidoglycan turnover. PMID:2066331

  5. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate

    PubMed Central

    Baumann, Anna-Maria T.; Bakkers, Mark J. G.; Buettner, Falk F. R.; Hartmann, Maike; Grove, Melanie; Langereis, Martijn A.; de Groot, Raoul J.; Mühlenhoff, Martina

    2015-01-01

    Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host–pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1—a previously identified human candidate gene—is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. PMID:26169044

  6. Application of reverse-phase HPLC to quantify oligopeptide acetylation eliminates interference from unspecific acetyl CoA hydrolysis

    PubMed Central

    Evjenth, Rune; Hole, Kristine; Ziegler, Mathias; Lillehaug, Johan R

    2009-01-01

    Protein acetylation is a common modification that plays a central role in several cellular processes. The most widely used methods to study these modifications are either based on the detection of radioactively acetylated oligopetide products or an enzyme-coupled reaction measuring conversion of the acetyl donor acetyl CoA to the product CoASH. Due to several disadvantages of these methods, we designed a new method to study oligopeptide acetylation. Based on reverse phase HPLC we detect both reaction products in a highly robust and reproducible way. The method reported here is also fully compatible with subsequent product analysis, e.g. by mass spectroscopy. The catalytic subunit, hNaa30p, of the human NatC protein N-acetyltransferase complex was used for N-terminal oligopeptide acetylation. We show that unacetylated and acetylated oligopeptides can be efficiently separated and quantified by the HPLC-based analysis. The method is highly reproducible and enables reliable quantification of both substrates and products. It is therefore well-suited to determine kinetic parameters of acetyltransferases. PMID:19660098

  7. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate.

    PubMed

    Baumann, Anna-Maria T; Bakkers, Mark J G; Buettner, Falk F R; Hartmann, Maike; Grove, Melanie; Langereis, Martijn A; de Groot, Raoul J; Mühlenhoff, Martina

    2015-01-01

    Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host-pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1--a previously identified human candidate gene--is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. PMID:26169044

  8. Evaluating Reliability and Predictive Validity of the Persian Translation of Quantitative Checklist for Autism in Toddlers (Q-CHAT)

    PubMed Central

    Mohammadian, Mehrdad; Mohammadi, Mohammad Reza; Karimi, Issa

    2015-01-01

    Objective: Early screening of autism increases the chance of receiving timely intervention. Using the Parent Report Questionnaires is effective in screening autism. The Q-CHAT is a new instrument that has shown several advantages than other screening tools. Because there is no adequate tool for the early screening of autistic traits in Iranian children, we aimed to investigate the adequacy of the Persian translation of Q-CHAT. Method: At first, we prepared the Persian translation of the Quantitative Checklist for Autism in Toddlers (Q-CHAT). After that, an appropriate sample was selected and the check list was administered. Our sample included 100 children in two groups (typically developing and autistic children) who had been selected conveniently. Pearson’s r was used to determine test-retest reliability, and Cronbach’s alpha coefficient was used to explore the internal consistency of Q-CHAT. We used the receiver operating characteristics curve (ROC) to investigate whether Q-CHAT can adequately discriminate between typically developing and ASD children or not. Data analysis was carried out by SPSS 19. Result: The typically developing group consisted of 50 children with the mean age of 27.14 months, and the ASD group included50 children with the mean age of 29.62 months. The mean of the total score for the typically developing group was 22.4 (SD=6.26) on Q-CHAT and it was 50.94 (SD=12.35) for the ASD group, which was significantly different (p=0.00).The Cronbach’s alpha coefficient of the checklist was 0.886, and test-retest reliability was calculated as 0.997 (p<0.01). The estimated area under the curve (AUC) was 0.971. It seems that the total score equal to 30 can be a good cut point to identify toddlers who are at risk of autism (sensitivity= 0.96 and specificity= 0.90). Conclusion: The Persian translation of Q-CHAT has good reliability and predictive validity and can be used as a screening tool to detect 18 to 24 months old children who are at risk of

  9. Glutathione transferase mimics: micellar catalysis of an enzymic reaction.

    PubMed Central

    Lindkvist, B; Weinander, R; Engman, L; Koetse, M; Engberts, J B; Morgenstern, R

    1997-01-01

    Substances that mimic the enzyme action of glutathione transferases (which serve in detoxification) are described. These micellar catalysts enhance the reaction rate between thiols and activated halogenated nitroarenes as well as alpha,beta-unsaturated carbonyls. The nucleophilic aromatic substitution reaction is enhanced by the following surfactants in descending order: poly(dimethyldiallylammonium - co - dodecylmethyldiallylammonium) bromide (86/14) >>cetyltrimethylammonium bromide>zwittergent 3-16 (n-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulphonate)>zwittergent+ ++ 3-14 (n-tetradecyl-N,N-dimethyl - 3 - ammonio -1 - propanesulphonate) approximately N,N - dimethyl - laurylamine N-oxide>N,N-dimethyloctylamine N-oxide. The most efficient catalyst studied is a polymeric material that incorporates surfactant properties (n-dodecylmethyldiallylammonium bromide) and opens up possibilities for engineering sequences of reactions on a polymeric support. Michael addition to alpha,beta-unsaturated carbonyls is exemplified by a model substance, trans-4-phenylbut-3-en-2-one, and a toxic compound that is formed during oxidative stress, 4-hydroxy-2-undecenal. The latter compound is conjugated with the highest efficiency of those tested. Micellar catalysts can thus be viewed as simple models for the glutathione transferases highlighting the influence of a positive electrostatic field and a non-specific hydrophobic binding site, pertaining to two catalytic aspects, namely thiolate anion stabilization and solvent shielding. PMID:9173899

  10. Nucleotidyl transferase assisted DNA labeling with different click chemistries

    PubMed Central

    Winz, Marie-Luise; Linder, Eva Christina; André, Timon; Becker, Juliane; Jäschke, Andres

    2015-01-01

    Here, we present a simple, modular and efficient strategy that allows the 3′-terminal labeling of DNA, regardless of whether it has been chemically or enzymatically synthesized or isolated from natural sources. We first incorporate a range of modified nucleotides at the 3′-terminus, using terminal deoxynucleotidyl transferase. In the second step, we convert the incorporated nucleotides, using either of four highly efficient click chemistry-type reactions, namely copper-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, Staudinger ligation or Diels-Alder reaction with inverse electron demand. Moreover, we create internal modifications, making use of either ligation or primer extension, after the nucleotidyl transferase step, prior to the click reaction. We further study the influence of linker variants on the reactivity of azides in different click reactions. We find that different click reactions exhibit distinct substrate preferences, a fact that is often overlooked, but should be considered when labeling oligonucleotides or other biomolecules with click chemistry. Finally, our findings allowed us to extend our previously published RNA labeling strategy to the use of a different copper-free click chemistry, namely the Staudinger ligation. PMID:26013812

  11. Teachers' instructional goals for science practice: Identifying knowledge gaps using cultural-historical activity theory (CHAT)

    NASA Astrophysics Data System (ADS)

    Farrar, Cynthia Hamen

    In AP Biology, the course goal, with respect to scientific acts and reasoning, has recently shifted toward a reform goal of science practice, where the goal is for students to have a scientific perspective that views science as a practice of a community rather than a body of knowledge. Given this recent shift, this study is interested in the gaps that may exist between an individual teacher's instructional goal and the goals of the AP Biology course. A Cultural-Historical Activity Theory (CHAT) methodology and perspective is used to analyze four teachers' knowledge, practice, and learning. Teachers have content knowledge for teaching, a form of knowledge that is unique for teaching called specialized content knowledge. This specialized content knowledge (SCK) defines their instructional goals, the student outcomes they ultimately aim to achieve with their students. The study employs a cultural-historical continuum of scientific acts and reasoning, which represents the development of the AP Biology goal over time, to study gaps in their instructional goal. The study also analyzes the contradictions within their teaching practice and how teachers address those contradictions to shift their instructional practice and learn. The findings suggest that teachers have different interpretations of the AP Biology goals of science practice, placing their instructional goal at different points along the continuum. Based on the location of their instructional goal, different micro-communities of teachers exist along the continuum, comprised of teachers with a shared goal, language, and culture of their AP Biology teaching. The in-depth study of one teacher's AP Biology teaching, using a CHAT perspective, provides a means for studying the mechanisms that connect SCK to classroom actions and ultimately to instructional practice. CHAT also reveals the nature and importance of contradictions or cognitive dissonance in teacher learning and the types of support teachers need to

  12. The identification of five novel genes in the cri-du-chat critical region

    SciTech Connect

    Simmons, A.D.; Gallardo, T.D.; Lovett, M.

    1994-09-01

    Cri-du-chat is a contiguous gene syndrome associated with deletions in the short arm of chromosome 5 (chr 5). Chr 5p-specific markers have been used to define two critical regions: a larynx malformation region, located at 5p15.3, and a region responsible for the remaining clinical features of the syndrome, which maps to 5p15.2. Thirty cosmids that map to this latter region have been isolated from the LANL chr 5-specific library using 5 STSs. More recently, we have constructed a YAC contig of the region which encompasses 2-3 Mb. The 30 framework cosmids were used in a direct selection with cDNAs from placenta, activated T-cells and cerebellum to isolate an initial set of expressed sequences from this region. Since no genes, to date, have been isolated or localized within the cri-du-chat deletion, a cosmid containing a control reporter gene (ANX6) was used to monitor enrichment. ANX6 cDNAs were enriched by several thousand-fold in the selected cDNAs. A total of nine non overlapping cDNA fragments were obtained from the cDNA pools. These have been ordered within the YAC contig, map to 5 discrete cosmid sets in the critical region and thus conservatively represent five discrete transcription units. The DNA sequences of these fragments are novel by sequence database comparisons. PCR primers were constructed and were used to confirm gene placements in the YAC contig, as well as to investigate the expression profile of these genes in several different tissues and cell types. In one case, these primer sets enabled two of the nine fragments to be linked into a larger cDNA. The nine cDNAs showed various patterns of differential expression in a panel of tissues. These expressed sequences represent the first genes isolated within the cri-du-chat critical region and represent the initial steps in the derivation of a comprehensive inventory and expression profile of the estimated 100 genes that may reside in this region.

  13. Acetylation of C/EBPα inhibits its granulopoietic function

    PubMed Central

    Bararia, Deepak; Kwok, Hui Si; Welner, Robert S.; Numata, Akihiko; Sárosi, Menyhárt B.; Yang, Henry; Wee, Sheena; Tschuri, Sebastian; Ray, Debleena; Weigert, Oliver; Levantini, Elena; Ebralidze, Alexander K.; Gunaratne, Jayantha; Tenen, Daniel G.

    2016-01-01

    CCAAT/enhancer-binding protein alpha (C/EBPα) is an essential transcription factor for myeloid lineage commitment. Here we demonstrate that acetylation of C/EBPα at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBPα DNA-binding ability and modulates C/EBPα transcriptional activity. Acetylated C/EBPα is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)- mediated granulocytic differentiation of 32Dcl3 cells. C/EBPα mutants that mimic acetylation failed to induce granulocytic differentiation in C/EBPα-dependent assays, in both cell lines and in primary hematopoietic cells. Our data uncover GCN5 as a negative regulator of C/EBPα and demonstrate the importance of C/EBPα acetylation in myeloid differentiation. PMID:27005833

  14. Rapid test for acetyl-methyl-carbinol formation by Enterobacteriaceae.

    PubMed Central

    Qadri, S M; Nichols, C W; Qadri, S G; Villarreal, A

    1978-01-01

    A modified Voges-Proskauer test is described which distinguishes within 4 to 8 hours between organisms that can produce acetyl-methyl-carbinol (acetoin) from glucose fermentation and those that cannot. PMID:363745

  15. Acetylation of C/EBPα inhibits its granulopoietic function.

    PubMed

    Bararia, Deepak; Kwok, Hui Si; Welner, Robert S; Numata, Akihiko; Sárosi, Menyhárt B; Yang, Henry; Wee, Sheena; Tschuri, Sebastian; Ray, Debleena; Weigert, Oliver; Levantini, Elena; Ebralidze, Alexander K; Gunaratne, Jayantha; Tenen, Daniel G

    2016-01-01

    CCAAT/enhancer-binding protein alpha (C/EBPα) is an essential transcription factor for myeloid lineage commitment. Here we demonstrate that acetylation of C/EBPα at lysine residues K298 and K302, mediated at least in part by general control non-derepressible 5 (GCN5), impairs C/EBPα DNA-binding ability and modulates C/EBPα transcriptional activity. Acetylated C/EBPα is enriched in human myeloid leukaemia cell lines and acute myeloid leukaemia (AML) samples, and downregulated upon granulocyte-colony stimulating factor (G-CSF)- mediated granulocytic differentiation of 32Dcl3 cells. C/EBPα mutants that mimic acetylation failed to induce granulocytic differentiation in C/EBPα-dependent assays, in both cell lines and in primary hematopoietic cells. Our data uncover GCN5 as a negative regulator of C/EBPα and demonstrate the importance of C/EBPα acetylation in myeloid differentiation. PMID:27005833

  16. Data detailing the platelet acetyl-lysine proteome

    PubMed Central

    Aslan, Joseph E.; David, Larry L.; McCarty, Owen J.T.

    2015-01-01

    Here we detail proteomics data that describe the acetyl-lysine proteome of blood platelets (Aslan et al., 2015 [1]). An affinity purification – mass spectrometry (AP-MS) approach was used to identify proteins modified by Nε-lysine acetylation in quiescent, washed human platelets. The data provide insights into potential regulatory mechanisms of platelet function mediated by protein lysine acetylation. Additionally, as platelets are anucleate and lack histone proteins, they offer a unique and valuable system to study the regulation of cytosolic proteins by lysine acetylation. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Vizcaino et al., 2014 [2]) via with PRIDE partner repository with the dataset identifier PXD002332. PMID:26904711

  17. Data detailing the platelet acetyl-lysine proteome.

    PubMed

    Aslan, Joseph E; David, Larry L; McCarty, Owen J T

    2015-12-01

    Here we detail proteomics data that describe the acetyl-lysine proteome of blood platelets (Aslan et al., 2015 [1]). An affinity purification - mass spectrometry (AP-MS) approach was used to identify proteins modified by Nε-lysine acetylation in quiescent, washed human platelets. The data provide insights into potential regulatory mechanisms of platelet function mediated by protein lysine acetylation. Additionally, as platelets are anucleate and lack histone proteins, they offer a unique and valuable system to study the regulation of cytosolic proteins by lysine acetylation. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium (Vizcaino et al., 2014 [2]) via with PRIDE partner repository with the dataset identifier PXD002332. PMID:26904711

  18. Partially Acetylated Sugarcane Bagasse For Wicking Oil From Contaminated Wetlands

    EPA Science Inventory

    Sugarcane bagasse was partially acetylated to enhance its oil-wicking ability in saturated environments while holding moisture for hydrocarbon biodegradation. The water sorption capacity of raw bagasse was reduced fourfold after treatment, which indicated considerably increased ...

  19. Rapid test for acetyl-methyl-carbinol formation by Enterobacteriaceae.

    PubMed

    Qadri, S M; Nichols, C W; Qadri, S G; Villarreal, A

    1978-10-01

    A modified Voges-Proskauer test is described which distinguishes within 4 to 8 hours between organisms that can produce acetyl-methyl-carbinol (acetoin) from glucose fermentation and those that cannot. PMID:363745

  20. Mechanistic insights into the regulation of metabolic enzymes by acetylation

    PubMed Central

    2012-01-01

    The activity of metabolic enzymes is controlled by three principle levels: the amount of enzyme, the catalytic activity, and the accessibility of substrates. Reversible lysine acetylation is emerging as a major regulatory mechanism in metabolism that is involved in all three levels of controlling metabolic enzymes and is altered frequently in human diseases. Acetylation rivals other common posttranslational modifications in cell regulation not only in the number of substrates it modifies, but also the variety of regulatory mechanisms it facilitates. PMID:22826120

  1. 21 CFR 172.372 - N-Acetyl-L-methionine.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false N-Acetyl-L-methionine. 172.372 Section 172.372 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.372 N-Acetyl-L-methionine....

  2. Olig1 Acetylation and Nuclear Export Mediate Oligodendrocyte Development

    PubMed Central

    Dai, Jinxiang; Bercury, Kathryn K.; Jin, Weilin

    2015-01-01

    The oligodendrocyte transcription factor Olig1 is critical for both oligodendrocyte development and remyelination in mice. Nuclear to cytoplasmic translocation of Olig1 protein occurs during brain development and in multiple sclerosis, but the detailed molecular mechanism of this translocation remains elusive. Here, we report that Olig1 acetylation and deacetylation drive its active translocation between the nucleus and the cytoplasm in both mouse and rat oligodendrocytes. We identified three functional nuclear export sequences (NES) localized in the basic helix-loop-helix domain and one specific acetylation site at Lys 150 (human Olig1) in NES1. Olig1 acetylation and deacetylation are regulated by the acetyltransferase CREB-binding protein and the histone deacetylases HDAC1, HDAC3, and HDAC10. Acetylation of Olig1 decreased its chromatin association, increased its interaction with inhibitor of DNA binding 2 and facilitated its retention in the cytoplasm of mature oligodendrocytes. These studies establish that acetylation of Olig1 regulates its chromatin dissociation and subsequent translocation to the cytoplasm and is required for its function in oligodendrocyte maturation. SIGNIFICANCE STATEMENT The nuclear to cytoplasmic translocation of Olig1 protein has been observed during mouse and human brain development and in multiple sclerosis in several studies, but the detailed molecular mechanism of this translocation remains elusive. Here, we provide insight into the mechanism by which acetylation of Olig1 regulates its unique nuclear-cytoplasmic shuttling during oligodendrocyte development and how the acetylation status of Olig1 modulates its distinct function in the nucleus versus the cytoplasm. The current study provides a unique example of a lineage-specific transcription factor that is actively translocated from the nucleus to the cytoplasm as the cell differentiates. Importantly, we demonstrate that this process is tightly controlled by acetylation at a single

  3. Nucleosome Dancing at the Tempo of Histone Tail Acetylation

    PubMed Central

    Galvani, Angélique; Thiriet, Christophe

    2015-01-01

    The impact of histone acetylation on transcription was revealed over 50 years ago by Allfrey and colleagues. However, it took decades for an understanding of the fine mechanism by which this posttranslational modification affects chromatin structure and promotes transcription. Here, we review breakthroughs linking histone tail acetylation, histone dynamics, and transcription. We also discuss the histone exchange during transcription and highlight the important function of a pool of non-chromatinized histones in chromatin dynamics. PMID:26184324

  4. An acetylation switch controls TDP-43 function and aggregation propensity.

    PubMed

    Cohen, Todd J; Hwang, Andrew W; Restrepo, Clark R; Yuan, Chao-Xing; Trojanowski, John Q; Lee, Virginia M Y

    2015-01-01

    TDP-43 pathology is a disease hallmark that characterizes amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP). Although a critical role for TDP-43 as an RNA-binding protein has emerged, the regulation of TDP-43 function is poorly understood. Here, we identify lysine acetylation as a novel post-translational modification controlling TDP-43 function and aggregation. We provide evidence that TDP-43 acetylation impairs RNA binding and promotes accumulation of insoluble, hyper-phosphorylated TDP-43 species that largely resemble pathological inclusions in ALS and FTLD-TDP. Moreover, biochemical and cell-based assays identify oxidative stress as a signalling cue that promotes acetylated TDP-43 aggregates that are readily engaged by the cellular defense machinery. Importantly, acetylated TDP-43 lesions are found in ALS patient spinal cord, indicating that aberrant TDP-43 acetylation and loss of RNA binding are linked to TDP-43 proteinopathy. Thus, modulating TDP-43 acetylation represents a plausible strategy to fine-tune TDP-43 activity, which could provide new therapeutic avenues for TDP-43 proteinopathies. PMID:25556531

  5. Effects of peptide acetylation and dimethylation on electrospray ionization efficiency.

    PubMed

    Cho, Kyung-Cho; Kang, Jeong Won; Choi, Yuri; Kim, Tae Woo; Kim, Kwang Pyo

    2016-02-01

    Peptide acetylation and dimethylation have been widely used to derivatize primary amino groups (peptide N-termini and the ε-amino group of lysines) for chemical isotope labeling of quantitative proteomics or for affinity tag labeling for selection and enrichment of labeled peptides. However, peptide acetylation results in signal suppression during electrospray ionization (ESI) due to charge neutralization. In contrast, dimethylated peptides show increased ionization efficiency after derivatization, since dimethylation increases hydrophobicity and maintains a positive charge on the peptide under common LC conditions. In this study, we quantitatively compared the ESI efficiencies of acetylated and dimethylated model peptides and tryptic peptides of BSA. Dimethylated peptides showed higher ionization efficiency than acetylated peptides for both model peptides and tryptic BSA peptides. At the proteome level, peptide dimethylation led to better protein identification than peptide acetylation when tryptic peptides of mouse brain lysate were analyzed with LC-ESI-MS/MS. These results demonstrate that dimethylation of tryptic peptides enhanced ESI efficiency and provided up to two-fold improved protein identification sensitivity in comparison with acetylation. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26889926

  6. Acetyl radical generation in cigarette smoke: Quantification and simulations

    NASA Astrophysics Data System (ADS)

    Hu, Na; Green, Sarah A.

    2014-10-01

    Free radicals are present in cigarette smoke and can have a negative effect on human health. However, little is known about their formation mechanisms. Acetyl radicals were quantified in tobacco smoke and mechanisms for their generation were investigated by computer simulations. Acetyl radicals were trapped from the gas phase using 3-amino-2, 2, 5, 5-tetramethyl-proxyl (3AP) on solid support to form stable 3AP adducts for later analysis by high-performance liquid chromatography (HPLC), mass spectrometry/tandem mass spectrometry (MS-MS/MS) and liquid chromatography-mass spectrometry (LC-MS). Simulations were performed using the Master Chemical Mechanism (MCM). A range of 10-150 nmol/cigarette of acetyl radical was measured from gas phase tobacco smoke of both commercial and research cigarettes under several different smoking conditions. More radicals were detected from the puff smoking method compared to continuous flow sampling. Approximately twice as many acetyl radicals were trapped when a glass fiber particle filter (GF/F specifications) was placed before the trapping zone. Simulations showed that NO/NO2 reacts with isoprene, initiating chain reactions to produce hydroxyl radical, which abstracts hydrogen from acetaldehyde to generate acetyl radical. These mechanisms can account for the full amount of acetyl radical detected experimentally from cigarette smoke. Similar mechanisms may generate radicals in second hand smoke.

  7. An acetylation switch controls TDP-43 function and aggregation propensity

    PubMed Central

    Cohen, Todd J.; Hwang, Andrew W.; Restrepo, Clark R.; Yuan, Chao-Xing; Trojanowski, John Q.; Lee, Virginia M.Y.

    2015-01-01

    TDP-43 pathology is a disease hallmark that characterizes amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD-TDP). Although a critical role for TDP-43 as an RNA-binding protein has emerged, the regulation of TDP-43 function is poorly understood. Here we identify lysine acetylation as a novel post-translational modification controlling TDP-43 function and aggregation. We provide evidence that TDP-43 acetylation impairs RNA-binding and promotes accumulation of insoluble, hyper-phosphorylated TDP-43 species that largely resemble pathological inclusions in ALS and FTLD-TDP. Moreover, biochemical and cell-based assays identify oxidative stress as a signaling cue that promotes acetylated TDP-43 aggregates that are readily engaged by the cellular defense machinery. Importantly, acetylated TDP-43 lesions are found in ALS patient spinal cord, indicating that aberrant TDP-43 acetylation and loss of RNA binding are linked to TDP-43 proteinopathy. Thus, modulating TDP-43 acetylation represents a plausible strategy to fine-tune TDP-43 activity, which could provide new therapeutic avenues for TDP-43 proteinopathies. PMID:25556531

  8. Acetyl Radical Generation in Cigarette Smoke: Quantification and Simulations

    PubMed Central

    Hu, Na; Green, Sarah A.

    2014-01-01

    Free radicals are present in cigarette smoke and can have a negative effect on human health. However, little is known about their formation mechanisms. Acetyl radicals were quantified in tobacco smoke and mechanisms for their generation were investigated by computer simulations. Acetyl radicals were trapped from the gas phase using 3-amino-2, 2, 5, 5-tetramethyl-proxyl (3AP) on solid support to form stable 3AP adducts for later analysis by high performance liquid chromatography (HPLC), mass spectrometry/tandem mass spectrometry (MS-MS/MS) and liquid chromatography–mass spectrometry (LC-MS). Simulations were performed using the Master Chemical Mechanism (MCM). A range of 10–150 nmol/cigarette of acetyl radical was measured from gas phase tobacco smoke of both commerial and research cigarettes under several different smoking conditions. More radicals were detected from the puff smoking method compared to continuous flow sampling. Approximately twice as many acetyl radicals were trapped when a glass filber particle filter (GF/F specifications) was placed before the trapping zone. Simulations showed that NO/NO2 reacts with isoprene, initiating chain reactions to produce hydroxyl radical, which abstracts hydrogen from acealdehyde to generate acetyl radical. These mechanisms can account for the full amount of acetyl radical detected experimentally from cigarette smoke. Similar mechanisms may generate radicals in second hand smoke. PMID:25253993

  9. Methods to detect NF-κB Acetylation and Methylation

    PubMed Central

    Chen, JinJing; Chen, Lin-Feng

    2015-01-01

    Summary Post-translational modifications of NF-κB, including acetylation and methylation, have emerged as an important regulatory mechanism for determining the duration and strength of NF-κB nuclear activity as well as its transcriptional output. Within the seven NF-κB family proteins, the RelA subunit of NF-κB is the most studied for its regulation by lysine acetylation and methylation. Acetylation or methylation at different lysine residues modulates distinct functions of NF-κB, including DNA binding and transcription activity, protein stability, and its interaction with NF-κB modulators. Here, we describe the experimental methods to monitor the in vitro and in vivo acetylated or methylated forms of NF-κB. These methods include radiolabeling the acetyl- or methyl- groups and immunoblotting with pan or site-specific acetyl- or methyl-lysine antibodies. Radiolabeling is useful in the initial validation of the modifications. Immunoblotting with antibodies provides a rapid and powerful approach to detect and analyze the functions of these modifications in vitro and in vivo. PMID:25736763

  10. What Are Youth Asking About Drugs? A Report of NIDA Drug Facts Chat Day.

    PubMed

    Morton, Cory M; Hoefinger, Heidi; Linn-Walton, Rebecca; Aikins, Ross; Falkin, Gregory P

    2015-01-01

    The current study analyzes a sample of questions about drugs asked online by youth who participated in the National Institute on Drug Abuse's (NIDA) "Drug Facts Chat Day." The types of drugs youth asked about were coded into 17 substance categories, and the topics they raised were coded into seven thematic categories. The top five queried drugs were marijuana (16.4%), alcohol (8.5%), tobacco (6%), cocaine (5.7), and pharmaceutical drugs (4.5%). The effects of drug use, experience of being high, the addictiveness of drugs, pharmacology, and drug sales were among the more common types of questions to emerge but varied depending on the substance. These findings show the types of information young people are seeking about drugs and have clear implications to inform youth drug education programs. PMID:26862133

  11. 2012 ARPA-E Energy Innovation Summit: Fireside Chat with Steven Chu and Bill Gates

    SciTech Connect

    Chu, Steven; Gates, Bill; Podesta, John

    2012-02-28

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. This video captures a session called 'Fireside Chat' that featured Steven Chu, the Secretary of Energy, and Bill Gates, Chairman of Microsoft Corporation. The session is moderated by John Podesta, Chair of the Center for American Progress. Energy Secretary Steven Chu and Microsoft Founder and Chairman Bill Gates exchanged ideas about how small businesses and innovators can overcome the challenges that face many startups.

  12. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing

    PubMed Central

    Yeo, Jaeryong; Lee, Juyeong

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers’ online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans’ interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users. PMID:26849568

  13. 2012 ARPA-E Energy Innovation Summit: Fireside Chat with Steven Chu and Bill Gates

    ScienceCinema

    Chu, Steven (U.S. Department of Energy Secretary); Gates, Bill (Microsoft, Chairman); Podesta, John (Center for American Progress, Chair and Counselor)

    2012-03-21

    The third annual ARPA-E Energy Innovation Summit was held in Washington D.C. in February, 2012. The event brought together key players from across the energy ecosystem - researchers, entrepreneurs, investors, corporate executives, and government officials - to share ideas for developing and deploying the next generation of energy technologies. This video captures a session called 'Fireside Chat' that featured Steven Chu, the Secretary of Energy, and Bill Gates, Chairman of Microsoft Corporation. The session is moderated by John Podesta, Chair of the Center for American Progress. Energy Secretary Steven Chu and Microsoft Founder and Chairman Bill Gates exchanged ideas about how small businesses and innovators can overcome the challenges that face many startups.

  14. What Makes Sports Fans Interactive? Identifying Factors Affecting Chat Interactions in Online Sports Viewing.

    PubMed

    Ko, Minsam; Yeo, Jaeryong; Lee, Juyeong; Lee, Uichin; Jang, Young Jae

    2016-01-01

    Sports fans are able to watch games from many locations using TV services while interacting with other fans online. In this paper, we identify the factors that affect sports viewers' online interactions. Using a large-scale dataset of more than 25 million chat messages from a popular social TV site for baseball, we extract various game-related factors, and investigate the relationships between these factors and fans' interactions using a series of multiple regression analyses. As a result, we identify several factors that are significantly related to viewer interactions. In addition, we determine that the influence of these factors varies according to the user group; i.e., active vs. less active users, and loyal vs. non-loyal users. PMID:26849568

  15. On-Line "Chat Room" Tutorials—An Unusual Gender Bias in Computer Use

    NASA Astrophysics Data System (ADS)

    Kimbrough, Doris R.

    1999-09-01

    Research into gender bias in attitudes, access, and effectiveness associated with computers has produced conflicting results, resulting in conflicting opinions as to whether a technological gender gap favoring male students exists. No previous study, however, has ever demonstrated a preference for female use of a particular computer application. This work describes gender differences in the use of on-line ("chat room") tutorials by non-traditional chemistry students enrolled in distance learning sections of a general chemistry course. Higher percentages of female students participated in the on-line tutorials and they participated with greater frequency than male students. Furthermore, the correlation between frequency of participation and course performance was higher among the female students. Various explanations for this unusual gender bias are offered, and the conclusion that the diversity of computer applications available today requires that research into gender bias refrain from viewing the computer as a single entity is supported.

  16. From pen pals to chat rooms: the impact of social media on Middle Eastern Society.

    PubMed

    Hatfield, Elaine; Rapson, Richard L

    2015-01-01

    In this article, we will discuss what is known about a surprisingly popular phenomenon in the Middle East-the use of social media to communicate. We will begin with a discussion of what "social media" sites are (sites such as Facebook, Your Middle East, YouTube, Flickr, Muslima.com, chat rooms, and instant messaging) and point out how common they are in the Middle East. Next, we will discuss the reasons why men and women are currently using Internet and social media. Finally, we will discuss what impact social media have had on politics, political dissent, education, and men's and women's relationships-and the impact they might be expected to have in future years. Finally, we will focus on the impact of such media on men's and women's relationships-including cross-gender friendships, romantic relationships, and sexual relationships. PMID:26090303

  17. Protein-energy malnutrition is frequent and precocious in children with cri du chat syndrome.

    PubMed

    Lefranc, Violaine; de Luca, Arnaud; Hankard, Régis

    2016-05-01

    Protein-energy malnutrition (PEM) is poorly reported in cri du chat syndrome (CDCS) (OMIM #123450), a genetic disease that causes developmental delay and global growth retardation. The objective was to determine the nutritional status at different ages in children with CDCS and factors associated with PEM. A questionnaire focused on growth and nutritional care was sent to 190 families. Among 36 analyzable questionnaires, growth and nutritional indices compatible with PEM occurred in 47% of patients: 19% before 6 months of age, 24% between 6-12 months and 34% after 12 months. Eight patients received enteral feeding. Speech therapy for swallowing education was performed more often in malnourished children (63% vs. 22%, P < 0.02). PEM is frequent and occurs early in this disease, requiring closed nutritional monitoring. © 2016 Wiley Periodicals, Inc. PMID:26872355

  18. Repowering with an integrated gasification-cascaded humidified advanced turbine (IG-CHAT) cycle

    SciTech Connect

    Freier, M.D.; Goldstein, H.N.; Swensen, E.C.

    1998-12-31

    This paper presents the results of an evaluation of repowering a typical US based coal fired power plant with a combination of coal gasification and advanced turbine technologies. In this case, an oxygen blown, fixed bed gasifier (based on British Gas-Lurgi technology) generates clean, low temperature, medium Btu gas which is fired in an advanced type of power cycle; namely, the Cascaded Humidified Advanced Turbine, or CHAT cycle which is defined and described below. This conceptual site repowering follows the same methodology and uses the same design parameters as in a recent evaluation of plant repowering utilizing a broad suite of advanced technologies, many of which are currently being demonstrated in the Clean Coal Technology Demonstration Program.

  19. Structure and stability of online chat networks built on emotion-carrying links

    NASA Astrophysics Data System (ADS)

    Gligorijević, Vladimir; Skowron, Marcin; Tadić, Bosiljka

    2013-02-01

    High-resolution data of online chats are studied as a physical system in the laboratory in order to quantify collective behavior of users. Our analysis reveals strong regularities characteristic of natural systems with additional features. In particular, we find self-organized dynamics with long-range correlations in user actions and persistent associations among users that have the properties of a social network. Furthermore, the evolution of the graph and its architecture with specific k-core structure are shown to be related with the type and the emotion arousal of exchanged messages. Partitioning of the graph by deletion of the links which carry high arousal messages exhibits critical fluctuations at the percolation threshold.

  20. Cognitive functioning in children with typical cri du chat (5p-) syndrome.

    PubMed

    Cornish, K M; Bramble, D; Munir, F; Pigram, J

    1999-04-01

    This study is the first attempt to assess systematically the cognitive functioning in children diagnosed with typical cri du chat syndrome (CDCS) using neuropsychological test measures. Twenty-six children aged between 6 years 4 months and 15 years 5 months (mean 8 years 3 months) completed a battery of tasks measuring IQ level, receptive and expressive language skills, and articulation. Twenty-four children were in the severe learning-disability range with no specific verbal or performance profile. Using more finely tuned measures of cognition, however, a clear discrepancy in the pattern of language functioning was found with better receptive than expressive language skills. One implication of these findings is that parents and professionals should be more optimistic about the capacities of children with CDCS to understand more complex verbal commands than their expressive language skills would suggest. PMID:10355811

  1. Evaluation of CancerChatCanada: a program of online support for Canadians affected by cancer

    PubMed Central

    Stephen, J.; Rojubally, A.; MacGregor, K.; McLeod, D.; Speca, M.; Taylor–Brown, J.; Fergus, K.; Collie, K.; Turner, J.; Sellick, S.; Mackenzie, G.

    2013-01-01

    Background Professional-led cancer support groups can improve quality of life and address unmet needs, but most Canadians affected by cancer do not have access to or do not make use of cancer support groups. A collaborative interdisciplinary team developed, operated, and evaluated Internet-based, professional-led, live-chat support groups (osgs) for cancer patients, caregivers, and survivors across Canada. Objective Our study aimed to report participant and participation characteristics in the pan-Canadian initiative known as CancerChatCanada, and to understand participant perspectives about the quality of communication and professional facilitation, overall satisfaction, and psychosocial benefits and outcomes. Methods Participants in osgs provided informed consent. Participant and participation characteristics were gathered from program data collection tools and are described using frequencies, means, and chi-squares. Patient, survivor, and caregiver perspectives were derived from 102 telephone interviews conducted after osg completion and subjected to a directed qualitative content analysis. Results The 55 professional-led osgs enrolled 351 participants from 9 provinces. More than half the participants came from rural or semirural areas, and more than 84% had no received previous cancer support. The attendance rate was 75%, the dropout rate was 26%, and 80% of participants were satisfied or very satisfied. The convenience and privacy of osgs were benefits. Meaningful communication about important and difficult topics, kinship and bonding with others, and improved mood and self-care were perceived outcomes. Conclusions Our results demonstrate that this collaborative initiative was successful in increasing reach and access, and that pan-Canadian, professional-led osgs provide psychosocial benefit to underserved and burdened cancer patients, survivors, and family caregivers. PMID:23443892

  2. [Selective N-heterylazimine inhibition of reactions catalyzed by rat liver glutathione transferase].

    PubMed

    Stulovskiĭ, A V; Voznyĭ, I V; Rozengart, E V; Suvorov, A A; Khovanskikh, A E

    1992-01-01

    Three reactions (nucleophile substitution, thiolysis and N-deoxygenation) catalyzed by rat liver glutathione transferase have been studied using several N-heterylazimine inhibitors. The inhibitors are sharply different in their effectiveness in the transferase reactions. Their efficiency depends on their structure. The mechanism which underlies the found regularities is suggested. PMID:1413125

  3. A propionate CoA-transferase of Ralstonia eutropha H16 with broad substrate specificity catalyzing the CoA thioester formation of various carboxylic acids.

    PubMed

    Lindenkamp, Nicole; Schürmann, Marc; Steinbüchel, Alexander

    2013-09-01

    In this study, we have investigated a propionate CoA-transferase (Pct) homologue encoded in the genome of Ralstonia eutropha H16. The corresponding gene has been cloned into the vector pET-19b to yield a histidine-tagged enzyme which was expressed in Escherichia coli BL21 (DE3). After purification, high-performance liquid chromatography/mass spectrometry (HPLC/MS) analyses revealed that the enzyme exhibits a broad substrate specificity for carboxylic acids. The formation of the corresponding CoA-thioesters of acetate using propionyl-CoA as CoA donor, and of propionate, butyrate, 3-hydroxybutyrate, 3-hydroxypropionate, crotonate, acrylate, lactate, succinate and 4-hydroxybutyrate using acetyl-CoA as CoA donor could be shown. According to the substrate specificity, the enzyme can be allocated in the family I of CoA-transferases. The apparent molecular masses as determined by gel filtration and detected by SDS polyacrylamide gel electrophoresis were 228 and 64 kDa, respectively, and point to a quaternary structure of the native enzyme (α4). The enzyme exhibited similarities in sequence and structure to the well investigated Pct of Clostridium propionicum. It does not contain the typical conserved (S)ENG motif, but the derived motif sequence EXG with glutamate 342 to be, most likely, the catalytic residue. Due to the homo-oligomeric structure and the sequence differences with the subclasses IA-C of family I CoA-transferases, a fourth subclass of family I is proposed, comprising - amongst others - the Pcts of R. eutropha H16 and C. propionicum. A markerless precise-deletion mutant R. eutropha H16∆pct was generated. The growth and accumulation behaviour of this mutant on gluconate, gluconate plus 3,3'-dithiodipropionic acid (DTDP), acetate and propionate was investigated but resulted in no observable phenotype. Both, the wild type and the mutant showed the same growth and storage behaviour with these carbon sources. It is probable that R. eutropha H16 is upregulating

  4. Glutathione S-transferase class {pi} polymorphism in baboons

    SciTech Connect

    Aivaliotis, M.J.; Cantu, T.; Gilligan, R.

    1995-02-01

    Glutathione S-transferase (GST) comprises a family of isozymes with broad substrate specificities. One or more GST isozymes are present in most animal tissues and function in several detoxification pathways through the conjugation of reduced glutathione with various electrophiles, thereby reducing their potential toxicity. Four soluble GST isozymes encoded by genes on different chromosomes have been identified in humans. The acidic class pi GST, GSTP (previously designated GST-3), is widely distributed in adult tissues and appears to be the only GST isozyme present in leukocytes and placenta. Previously reported electrophoretic analyses of erythrocyte and leukocyte extracts revealed single bands of activity, which differed slightly in mobility between the two cell types, or under other conditions, a two-banded pattern. To our knowledge, no genetically determined polymorphisms have previously been reported in GSTP from any species. We now report a polymorphism of GSTP in baboon leukocytes, and present family data that verifies autosomal codominant inheritance. 14 refs., 2 figs., 1 tab.

  5. Recombinant baculovirus vectors expressing glutathione-S-transferase fusion proteins.

    PubMed

    Davies, A H; Jowett, J B; Jones, I M

    1993-08-01

    Recombinant baculoviruses are a popular means of producing heterologous protein in eukaryotic cells. Purification of recombinant proteins away from the insect cell background can, however, remain an obstacle for many developments. Recently, prokaryotic fusion protein expression systems have been developed allowing single-step purification of the heterologous protein and specific proteolytic cleavage of the affinity tag moiety from the desired antigen. Here we report the introduction of these attributes to the baculovirus system. "Baculo-GEX" vectors enable baculovirus production of fusion proteins with the above advantages, but in a eukaryotic post-translational processing environment. Glutathione-S-transferase (GST) fusions are stable cytoplasmic proteins in insect cells and may therefore be released by sonication alone, avoiding the solubility problems and detergent requirements of bacterial systems. Thus large amounts of authentic antigen may be purified in a single, non-denaturing step. PMID:7763917

  6. Functional analysis and localisation of a delta-class glutathione S-transferase from Sarcoptes scabiei.

    PubMed

    Pettersson, Eva U; Ljunggren, Erland L; Morrison, David A; Mattsson, Jens G

    2005-01-01

    The mite Sarcoptes scabiei causes sarcoptic mange, or scabies, a disease that affects both animals and humans worldwide. Our interest in S. scabiei led us to further characterise a glutathione S-transferase. This multifunctional enzyme is a target for vaccine and drug development in several parasitic diseases. The S. scabiei glutathione S-transferase open reading frame reported here is 684 nucleotides long and yields a protein with a predicted molecular mass of 26 kDa. Through phylogenetic analysis the enzyme was classified as a delta-class glutathione S-transferase, and our paper is the first to report that delta-class glutathione S-transferases occur in organisms other than insects. The recombinant S. scabiei glutathione S-transferase was expressed in Escherichia coli via three different constructs and purified for biochemical analysis. The S. scabiei glutathione S-transferase was active towards the substrate 1-chloro-2,4-dinitrobenzene, though the positioning of fusion partners influenced the kinetic activity of the enzyme. Polyclonal antibodies raised against S. scabiei glutathione S-transferase specifically localised the enzyme to the integument of the epidermis and cavities surrounding internal organs in adult parasites. However, some minor staining of parasite intestines was observed. No staining was seen in host tissues, nor could we detect any antibody response against S. scabiei glutathione S-transferase in sera from naturally S. scabiei infected dogs or pigs. Additionally, the polyclonal sera raised against recombinant S. scabiei glutathione S-transferase readily detected a protein from mites, corresponding to the predicted size of native glutathione S-transferase. PMID:15619514

  7. A SUMO-acetyl switch in PXR biology.

    PubMed

    Cui, Wenqi; Sun, Mengxi; Zhang, Shupei; Shen, Xunan; Galeva, Nadezhda; Williams, Todd D; Staudinger, Jeff L

    2016-09-01

    Post-translational modification (PTM) of nuclear receptor superfamily members regulates various aspects of their biology to include sub-cellular localization, the repertoire of protein-binding partners, as well as their stability and mode of degradation. The nuclear receptor pregnane X receptor (PXR, NR1I2) is a master-regulator of the drug-inducible gene expression in liver and intestine. The PXR-mediated gene activation program is primarily recognized to increase drug metabolism, drug transport, and drug efflux pathways in these tissues. The activation of PXR also has important implications in significant human diseases including inflammatory bowel disease and cancer. Our recent investigations reveal that PXR is modified by multiple PTMs to include phosphorylation, SUMOylation, and ubiquitination. Using both primary cultures of hepatocytes and cell-based assays, we show here that PXR is modified through acetylation on lysine residues. Further, we show that increased acetylation of PXR stimulates its increased SUMO-modification to support active transcriptional suppression. Pharmacologic inhibition of lysine de-acetylation using trichostatin A (TSA) alters the sub-cellular localization of PXR in cultured hepatocytes, and also has a profound impact upon PXR transactivation capacity. Both the acetylation and SUMOylation status of the PXR protein is affected by its ability to associate with the lysine de-acetylating enzyme histone de-acetylase (HDAC)3 in a complex with silencing mediator of retinoic acid and thyroid hormone receptor (SMRT). Taken together, our data support a model in which a SUMO-acetyl 'switch' occurs such that acetylation of PXR likely stimulates SUMO-modification of PXR to promote the active repression of PXR-target gene expression. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie. PMID:26883953

  8. Identification of cellular factors binding to acetylated HIV-1 integrase.

    PubMed

    Allouch, Awatef; Cereseto, Anna

    2011-11-01

    The viral protein integrase (IN) catalyzes the integration of the HIV-1 cDNA into the host cellular genome. We have recently demonstrated that IN is acetylated by a cellular histone acetyltransferase, p300, which modifies three lysines located in the C-terminus of the viral factor (Cereseto et al. in EMBO J 24:3070-3081, 2005). This modification enhances IN catalytic activity, as demonstrated by in vitro assays. Consistently, mutations introduced in the targeted lysines greatly decrease the efficiency of HIV-1 integration. Acetylation was proven to regulate protein functions by modulating protein-protein interactions. HIV-1 to efficiently complete its replication steps, including the integration reaction, requires interacting with numerous cellular factors. Therefore, we sought to investigate whether acetylation might modulate the interaction between IN and the cellular factors. To this aim we performed a yeast two-hybrid screening that differs from the screenings so far performed (Rain et al. in Methods 47:291-297, 2009; Studamire and Goff in Retrovirology 5:48, 2008) for using as bait IN constitutively acetylated. From this analysis we have identified thirteen cellular factors involved in transcription, chromatin remodeling, nuclear transport, RNA binding, protein synthesis regulation and microtubule organization. To validate these interactions, binding assays were performed showing that acetylation increases the affinity of IN with specific factors. Nevertheless, few two-hybrid hits bind with the same affinity the acetylated and the unmodified IN. These results further underlie the relevance of IN post-translational modification by acetylation in HIV-1 replication cycle. PMID:20016921

  9. Enzymic synthesis of indole-3-acetyl-1-O-beta-d-glucose. I. Partial purification and characterization of the enzyme from Zea mays

    NASA Technical Reports Server (NTRS)

    Leznicki, A. J.; Bandurski, R. S.

    1988-01-01

    The first enzyme-catalyzed reaction leading from indole-3-acetic acid (IAA) to the myo-inositol esters of IAA is the synthesis of indole-3-acetyl-1-O-beta-D-glucose from uridine-5'-diphosphoglucose (UDPG) and IAA. The reaction is catalyzed by the enzyme, UDPG-indol-3-ylacetyl glucosyl transferase (IAA-glucose-synthase). This work reports methods for the assay of the enzyme and for the extraction and partial purification of the enzyme from kernels of Zea mays sweet corn. The enzyme has an apparent molecular weight of 46,500 an isoelectric point of 5.5, and its pH optimum lies between 7.3 and 7.6. The enzyme is stable to storage at zero degrees but loses activity during column chromatographic procedures which can be restored only fractionally by addition of column eluates. The data suggest either multiple unknown cofactors or conformational changes leading to activity loss.

  10. Aspirin inhibits glucose-6-phosphate dehydrogenase activity in HCT 116 cells through acetylation: Identification of aspirin-acetylated sites

    PubMed Central

    Ai, Guoqiang; Dachineni, Rakesh; Kumar, D. Ramesh; Alfonso, Lloyd F.; Marimuthu, Srinivasan; Bhat, G. Jayarama

    2016-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) catalyzes the first reaction in the pentose phosphate pathway, and generates ribose sugars, which are required for nucleic acid synthesis, and nicotinamide adenine dinucleotide phosphate (NADPH), which is important for neutralization of oxidative stress. The expression of G6PD is elevated in several types of tumor, including colon, breast and lung cancer, and has been implicated in cancer cell growth. Our previous study demonstrated that exposure of HCT 116 human colorectal cancer cells to aspirin caused acetylation of G6PD, and this was associated with a decrease in its enzyme activity. In the present study, this observation was expanded to HT-29 colorectal cancer cells, in order to compare aspirin-mediated acetylation of G6PD and its activity between HCT 116 and HT-29 cells. In addition, the present study aimed to determine the acetylation targets of aspirin on recombinant G6PD to provide an insight into the mechanisms of inhibition. The results demonstrated that the extent of G6PD acetylation was significantly higher in HCT 116 cells compared with in HT-29 cells; accordingly, a greater reduction in G6PD enzyme activity was observed in the HCT 116 cells. Mass spectrometry analysis of aspirin-acetylated G6PD (isoform a) revealed that aspirin acetylated a total of 14 lysine residues, which were dispersed throughout the length of the G6PD protein. One of the important amino acid targets of aspirin included lysine 235 (K235, in isoform a) and this corresponds to K205 in isoform b, which has previously been identified as being important for catalysis. Acetylation of G6PD at several sites, including K235 (K205 in isoform b), may mediate inhibition of G6PD activity, which may contribute to the ability of aspirin to exert anticancer effects through decreased synthesis of ribose sugars and NADPH. PMID:27356773

  11. Olig1 Acetylation and Nuclear Export Mediate Oligodendrocyte Development.

    PubMed

    Dai, Jinxiang; Bercury, Kathryn K; Jin, Weilin; Macklin, Wendy B

    2015-12-01

    The oligodendrocyte transcription factor Olig1 is critical for both oligodendrocyte development and remyelination in mice. Nuclear to cytoplasmic translocation of Olig1 protein occurs during brain development and in multiple sclerosis, but the detailed molecular mechanism of this translocation remains elusive. Here, we report that Olig1 acetylation and deacetylation drive its active translocation between the nucleus and the cytoplasm in both mouse and rat oligodendrocytes. We identified three functional nuclear export sequences (NES) localized in the basic helix-loop-helix domain and one specific acetylation site at Lys 150 (human Olig1) in NES1. Olig1 acetylation and deacetylation are regulated by the acetyltransferase CREB-binding protein and the histone deacetylases HDAC1, HDAC3, and HDAC10. Acetylation of Olig1 decreased its chromatin association, increased its interaction with inhibitor of DNA binding 2 and facilitated its retention in the cytoplasm of mature oligodendrocytes. These studies establish that acetylation of Olig1 regulates its chromatin dissociation and subsequent translocation to the cytoplasm and is required for its function in oligodendrocyte maturation. PMID:26631469

  12. Looking from a CHAT-IT perspective to undergraduate Mexican physics: organizational trajectories or professors as agents of change?

    NASA Astrophysics Data System (ADS)

    Kahveci, Ajda

    2010-09-01

    Recent elaborations on cultural-historical activity theory (CHAT) (Engeström et al., eds., Perspectives on activity theory. New York: Cambridge University Press, 1999) and its relation to organizational theories have produced a theoretical amalgam of these earlier ideas, which allow for the exploration of learning in formal organizational contexts such as schools. In this paper I reflect on Candela's work situated in undergraduate Mexican physics by drawing attention to the CHAT-IT framework (Ogawa et al., Educational Researcher 37(2):83-95, 2008) as a viable lens. I suggest that it is important to understand the historical development of the Mexican university as an educational organization as well as the role of physics professors as agents of change whose practices contribute to not only breaking classroom walls but also to transforming the organization affecting future activity systems.

  13. Health-related message boards/chat rooms on the Web: discussion content and implications for pharmaceutical sponsorships.

    PubMed

    Macias, Wendy; Lewis, Liza Stavchansky; Smith, Tenikka L

    2005-01-01

    This content analysis study examined health-related message boards to better understand who is using this on-line health information and support device and what topics they are discussing. Besides needing to understand this support and coping mechanism for individuals, this has become an increasingly important topic for health communicators to understand because the Health and Human Services' (HHS) Inspector General recently gave permission to a pharmaceutical manufacturer for sponsorship of a disease management chat room. Very little research has been done on the content of these message boards/chat rooms. Key findings include that the most commonly discussed medical topics were medical treatments and drugs (often specific brands) and that these boards are clearly important sources of information and emotional support. Implication and future research are discussed. PMID:16036729

  14. Genetic Association of CHAT rs3810950 and rs2177369 Polymorphisms with the Risk of Alzheimer's Disease: A Meta-Analysis

    PubMed Central

    Liu, Yong; Chen, Qicong; Liu, Xu; Dou, Mengmeng; Li, Silu; Zhou, Jiahui; Liu, Hong

    2016-01-01

    Choline acetyltransferase (CHAT) rs3810950 and rs2177369 polymorphisms have been implicated in susceptibility to Alzheimer's disease (AD). Due to the inconsistent results from previous studies, a meta-analysis was performed to estimate the association between these polymorphisms and AD risk more precisely. Pooled results of our meta-analysis indicated CHAT rs2177369 polymorphism was correlated with decreasing AD risk in one of five genetic models (dominant: OR = 0.77, 95% CI: 0.62–0.96), while rs3810950 mutant was associated with AD development in three models (allelic: OR = 1.18, 95% CI: 1.01–1.37, homozygous: OR = 1.63, 95% CI: 1.09–2.42, and recessive: OR = 1.65, 95% CI: 1.20–2.26). In subgroup analysis by ethnicity, the association between CHAT rs3810950 polymorphism and AD risk was just found in the recessive model (OR = 1.47, 95% CI: 1.05–2.07) among Caucasians, while four genetic models (allelic: OR = 1.23, 95% CI: 1.01–1.48; homozygous: OR = 2.24, 95% CI: 1.48–3.39; dominant: OR = 1.21, 95% CI: 1.06–1.40; and recessive: OR = 2.18, 95% CI: 1.45–3.29) assumed this association in Asians. In conclusion, our meta-analysis indicated CHAT rs2177369 polymorphism might play a protective role in AD, while rs3810950 variant was a risk factor for AD but its single heterozygous mutations might not influence susceptibility to AD. PMID:27597977

  15. Genetic Association of CHAT rs3810950 and rs2177369 Polymorphisms with the Risk of Alzheimer's Disease: A Meta-Analysis.

    PubMed

    Liu, Yong; Chen, Qicong; Liu, Xu; Dou, Mengmeng; Li, Silu; Zhou, Jiahui; Liu, Hong; Wu, Yongfu; Huang, Zunnan

    2016-01-01

    Choline acetyltransferase (CHAT) rs3810950 and rs2177369 polymorphisms have been implicated in susceptibility to Alzheimer's disease (AD). Due to the inconsistent results from previous studies, a meta-analysis was performed to estimate the association between these polymorphisms and AD risk more precisely. Pooled results of our meta-analysis indicated CHAT rs2177369 polymorphism was correlated with decreasing AD risk in one of five genetic models (dominant: OR = 0.77, 95% CI: 0.62-0.96), while rs3810950 mutant was associated with AD development in three models (allelic: OR = 1.18, 95% CI: 1.01-1.37, homozygous: OR = 1.63, 95% CI: 1.09-2.42, and recessive: OR = 1.65, 95% CI: 1.20-2.26). In subgroup analysis by ethnicity, the association between CHAT rs3810950 polymorphism and AD risk was just found in the recessive model (OR = 1.47, 95% CI: 1.05-2.07) among Caucasians, while four genetic models (allelic: OR = 1.23, 95% CI: 1.01-1.48; homozygous: OR = 2.24, 95% CI: 1.48-3.39; dominant: OR = 1.21, 95% CI: 1.06-1.40; and recessive: OR = 2.18, 95% CI: 1.45-3.29) assumed this association in Asians. In conclusion, our meta-analysis indicated CHAT rs2177369 polymorphism might play a protective role in AD, while rs3810950 variant was a risk factor for AD but its single heterozygous mutations might not influence susceptibility to AD. PMID:27597977

  16. Determination of NAT2 acetylation status in the Greenlandic population.

    PubMed

    Geller, Frank; Soborg, Bolette; Koch, Anders; Michelsen, Sascha Wilk; Bjorn-Mortensen, Karen; Carstensen, Lisbeth; Birch, Emilie; Nordholm, Anne Christine; Johansen, Marie Mila Broby; Børresen, Malene Landbo; Feenstra, Bjarke; Melbye, Mads

    2016-04-01

    N-acetyltransferase 2 (NAT2) is a well-studied phase II xenobiotic metabolizing enzyme relevant in drug metabolism and cancerogenesis. NAT2 activity is largely determined by genetic polymorphisms in the coding region of the corresponding gene. We investigated NAT2 acetylation status in 1556 individuals from Greenland based on four different single nucleotide polymorphism (SNP) panels and the tagging SNP rs1495741. There was good concordance between the NAT2 status inferred by the different SNP combinations. Overall, the fraction of slow acetylators was low with 17.5 % and varied depending on the degree of Inuit ancestry; in individuals with <50 % Inuit ancestry, we observed more than 25 % slow acetylators reflecting European ancestry. Greenland has a high incidence of tuberculosis, and individual dosing of isoniazid according to NAT2 status has been shown to improve treatment and reduce side effects. Our findings could be a first step in pharmacogenetics-based tuberculosis therapy in Greenland. PMID:25794903

  17. Synthetic biology for engineering acetyl coenzyme A metabolism in yeast.

    PubMed

    Nielsen, Jens

    2014-01-01

    The yeast Saccharomyces cerevisiae is a widely used cell factory for the production of fuels, chemicals, and pharmaceuticals. The use of this cell factory for cost-efficient production of novel fuels and chemicals requires high yields and low by-product production. Many industrially interesting chemicals are biosynthesized from acetyl coenzyme A (acetyl-CoA), which serves as a central precursor metabolite in yeast. To ensure high yields in production of these chemicals, it is necessary to engineer the central carbon metabolism so that ethanol production is minimized (or eliminated) and acetyl-CoA can be formed from glucose in high yield. Here the perspective of generating yeast platform strains that have such properties is discussed in the context of a major breakthrough with expression of a functional pyruvate dehydrogenase complex in the cytosol. PMID:25370498

  18. Synthesis of polyrotaxanes from acetyl-β-cyclodextrin

    NASA Astrophysics Data System (ADS)

    Ristić, I. S.; Nikolić, L.; Nikolić, V.; Ilić, D.; Budinski-Simendić, J.

    2011-12-01

    Polyrotaxanes are intermediary products in the synthesis of topological gels. They are created by inclusion complex formation of hydrophobic linear macromolecules with cyclodextrins or their derivatives. Then, pairs of cyclodextrin molecules with covalently linkage were practically forming the nodes of the semi-flexible polymer network. Such gels are called topological gels and they can absorb huge quantities of water due to the net flexibility allowing the poly(ethylene oxide) chains to slide through the cyclodextrin cavities, without being pulled out altogether. For polyrotaxane formation poly(ethylene oxide) was used like linear macromolecules. There are hydroxyl groups at poly(ethylene oxide) chains, whereby the linking of the voluminous molecules should be made. To avoid the reaction of cyclodextrin OH groups with stoppers, they should be protected by, e.g., acetylation. In this work, the acetylation of the OH groups of β-cyclodextrin was performed by acetic acid anhydride with iodine as the catalyst. The acetylation reaction was assessed by the FTIR and HPLC method. By the HPLC analysis was found that the acetylation was completed in 20 minutes. Inserting of poly(ethylene oxide) with 4000 g/mol molecule mass into acetyl-β-cyclodextrin with 2:1 poly(ethylene oxide) monomer unit to acetyl-β-cyclodextrin ratio was also monitored by FTIR, and it was found that the process was completed in 12 h at the temperature of 10°C. If the process is performed at temperatures above 10°C, or for periods longer than 12 hours, the process of uncontrolled hydrolysis of acetate groups was initiated.

  19. Interaction of RNA polymerase II with acetylated nucleosomal core particles

    SciTech Connect

    Pineiro, M.; Gonzalez, P.J.; Hernandez, F.; Palacian, E. )

    1991-05-31

    Chemical acetylation of nucleosomal cores is accompanied by an increase in their efficiency as in vitro transcription templates. Low amounts of acetic anhydride cause preferential modification of the amino-terminal tails of core histones. Modification of these domains, which causes moderate structural effects, is apparently correlated with the observed stimulation of RNA synthesis. In contrast, extensive modification of the globular regions of core histones, which is accompanied by a large structural relaxation of the particle, causes little additional effect on transcription. Acetylation of the amino-terminal domains of histones might stimulate transcription by changing the interaction of the histone tails with components of the transcriptional machinery.

  20. Histone acetylation: a switch between repressive and permissive chromatin

    PubMed Central

    Eberharter, Anton; Becker, Peter B.

    2002-01-01

    The organization of eukaryotic chromatin has a major impact on all nuclear processes involving DNA substrates. Gene expression is affected by the positioning of individual nucleosomes relative to regulatory sequence elements, by the folding of the nucleosomal fiber into higher-order structures and by the compartmentalization of functional domains within the nucleus. Because site-specific acetylation of nucleosomal histones influences all three aspects of chromatin organization, it is central to the switch between permissive and repressive chromatin structure. The targeting of enzymes that modulate the histone acetylation status of chromatin, in synergy with the effects mediated by other chromatin remodeling factors, is central to gene regulation. PMID:11882541

  1. Crystal structure of E. coli lipoprotein diacylglyceryl transferase.

    PubMed

    Mao, Guotao; Zhao, Yan; Kang, Xusheng; Li, Zhijie; Zhang, Yan; Wang, Xianping; Sun, Fei; Sankaran, Krishnan; Zhang, Xuejun C

    2016-01-01

    Lipoprotein biogenesis is essential for bacterial survival. Phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) is an integral membrane enzyme that catalyses the first reaction of the three-step post-translational lipid modification. Deletion of the lgt gene is lethal to most Gram-negative bacteria. Here we present the crystal structures of Escherichia coli Lgt in complex with phosphatidylglycerol and the inhibitor palmitic acid at 1.9 and 1.6 Å resolution, respectively. The structures reveal the presence of two binding sites and support the previously reported structure-function relationships of Lgt. Complementation results of lgt-knockout cells with different mutant Lgt variants revealed critical residues, including Arg143 and Arg239, that are essential for diacylglyceryl transfer. Using a GFP-based in vitro assay, we correlated the activities of Lgt with structural observations. Together, the structural and biochemical data support a mechanism whereby substrate and product, lipid-modified lipobox-containing peptide, enter and leave the enzyme laterally relative to the lipid bilayer. PMID:26729647

  2. Inactivation of Anopheles gambiae Glutathione Transferase ε2 by Epiphyllocoumarin

    PubMed Central

    Marimo, Patience; Hayeshi, Rose; Mukanganyama, Stanley

    2016-01-01

    Glutathione transferases (GSTs) are part of a major family of detoxifying enzymes that can catalyze the reductive dehydrochlorination of dichlorodiphenyltrichloroethane (DDT). The delta and epsilon classes of insect GSTs have been implicated in conferring resistance to this insecticide. In this study, the inactivation of Anopheles gambiae GSTε2 by epiphyllocoumarin (Tral 1) was investigated. Recombinant AgGSTε2 was expressed in Escherichia coli cells containing a pET3a-AGSTε2 plasmid and purified by affinity chromatography. Tral 1 was shown to inactivate GSTε2 both in a time-dependent manner and in a concentration-dependent manner. The half-life of GSTε2 in the presence of 25 μM ethacrynic acid (ETA) was 22 minutes and with Tral 1 was 30 minutes, indicating that Tral 1 was not as efficient as ETA as an inactivator. The inactivation parameters kinact and KI were found to be 0.020 ± 0.001 min−1 and 7.5 ± 2.1 μM, respectively, after 90 minutes of incubation. Inactivation of GSTε2 by Tral 1 implies that Tral 1 covalently binds to this enzyme in vitro and would be expected to exhibit time-dependent effects on the enzyme in vivo. Tral 1, therefore, would produce irreversible effects when used together with dichlorodiphenyltrichloroethane (DDT) in malaria control programmes where resistance is mediated by GSTs. PMID:26925266

  3. Crystal structure of E. coli lipoprotein diacylglyceryl transferase

    PubMed Central

    Mao, Guotao; Zhao, Yan; Kang, Xusheng; Li, Zhijie; Zhang, Yan; Wang, Xianping; Sun, Fei; Sankaran, Krishnan; Zhang, Xuejun C.

    2016-01-01

    Lipoprotein biogenesis is essential for bacterial survival. Phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) is an integral membrane enzyme that catalyses the first reaction of the three-step post-translational lipid modification. Deletion of the lgt gene is lethal to most Gram-negative bacteria. Here we present the crystal structures of Escherichia coli Lgt in complex with phosphatidylglycerol and the inhibitor palmitic acid at 1.9 and 1.6 Å resolution, respectively. The structures reveal the presence of two binding sites and support the previously reported structure–function relationships of Lgt. Complementation results of lgt-knockout cells with different mutant Lgt variants revealed critical residues, including Arg143 and Arg239, that are essential for diacylglyceryl transfer. Using a GFP-based in vitro assay, we correlated the activities of Lgt with structural observations. Together, the structural and biochemical data support a mechanism whereby substrate and product, lipid-modified lipobox-containing peptide, enter and leave the enzyme laterally relative to the lipid bilayer. PMID:26729647

  4. Benzene oxide is a substrate for glutathione S-transferases.

    PubMed

    Zarth, Adam T; Murphy, Sharon E; Hecht, Stephen S

    2015-12-01

    Benzene is a known human carcinogen which must be activated to benzene oxide (BO) to exert its carcinogenic potential. BO can be detoxified in vivo by reaction with glutathione and excretion in the urine as S-phenylmercapturic acid. This process may be catalyzed by glutathione S-transferases (GSTs), but kinetic data for this reaction have not been published. Therefore, we incubated GSTA1, GSTT1, GSTM1, and GSTP1 with glutathione and BO and quantified the formation of S-phenylglutathione. Kinetic parameters were determined for GSTT1 and GSTP1. At 37 °C, the putative Km and Vmax values for GSTT1 were 420 μM and 450 fmol/s, respectively, while those for GSTP1 were 3600 μM and 3100 fmol/s. GSTA1 and GSTM1 did not exhibit sufficient activity for determination of kinetic parameters. We conclude that GSTT1 is a critical enzyme in the detoxification of BO and that GSTP1 may also play an important role, while GSTA1 and GSTM1 seem to be less important. PMID:26554337

  5. Modulation of Rab GTPase function by a protein phosphocholine transferase.

    PubMed

    Mukherjee, Shaeri; Liu, Xiaoyun; Arasaki, Kohei; McDonough, Justin; Galán, Jorge E; Roy, Craig R

    2011-09-01

    The intracellular pathogen Legionella pneumophila modulates the activity of host GTPases to direct the transport and assembly of the membrane-bound compartment in which it resides. In vitro studies have indicated that the Legionella protein DrrA post-translationally modifies the GTPase Rab1 by a process called AMPylation. Here we used mass spectrometry to investigate post-translational modifications to Rab1 that occur during infection of host cells by Legionella. Consistent with in vitro studies, DrrA-mediated AMPylation of a conserved tyrosine residue in the switch II region of Rab1 was detected during infection. In addition, a modification to an adjacent serine residue in Rab1 was discovered, which was independent of DrrA. The Legionella effector protein AnkX was required for this modification. Biochemical studies determined that AnkX directly mediates the covalent attachment of a phosphocholine moiety to Rab1. This phosphocholine transferase activity used CDP-choline as a substrate and required a conserved histidine residue located in the FIC domain of the AnkX protein. During infection, AnkX modified both Rab1 and Rab35, which explains how this protein modulates membrane transport through both the endocytic and exocytic pathways of the host cell. Thus, phosphocholination of Rab GTPases represents a mechanism by which bacterial FIC-domain-containing proteins can alter host-cell functions. PMID:21822290

  6. Cri-Du-Chat Syndrome: Clinical Profile and Chromosomal Microarray Analysis in Six Patients.

    PubMed

    Espirito Santo, Layla Damasceno; Moreira, Lília Maria Azevedo; Riegel, Mariluce

    2016-01-01

    Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short arm of chromosome 5. The disease severity, levels of intellectual and developmental delay, and patient prognosis have been related to the size and position of the deletion. Aiming to establish genotype-phenotype correlations, we applied array-CGH to evaluate six patients carrying cytogenetically detected deletions of the short arm of chromosome 5 who were followed at a genetics community service. The patients' cytogenetic and clinical profiles were reevaluated. A database review was performed to predict additional genes and regulatory elements responsible for the characteristic phenotypic and behavioral traits of this disorder. Array-CGH analysis allowed for delineation of the terminal deletions, which ranged in size from approximately 11.2 Mb to 28.6 Mb, with breakpoints from 5p15.2 to 5p13. An additional dup(8)(p23) (3.5 Mb), considered to be a benign copy number variation, was also observed in one patient. The correlation coefficient value (ρ = 0.13) calculated indicated the presence of a weak relationship between developmental delay and deletion size. Genetic background, family history, epigenetic factors, quantitative trait locus polymorphisms, and environmental factors may also affect patient phenotype and must be taken into account in genotype-phenotype correlations. PMID:27144168

  7. Cri-Du-Chat Syndrome: Clinical Profile and Chromosomal Microarray Analysis in Six Patients

    PubMed Central

    Espirito Santo, Layla Damasceno; Moreira, Lília Maria Azevedo; Riegel, Mariluce

    2016-01-01

    Cri-du-chat syndrome is a chromosomal disorder caused by a deletion of the short arm of chromosome 5. The disease severity, levels of intellectual and developmental delay, and patient prognosis have been related to the size and position of the deletion. Aiming to establish genotype-phenotype correlations, we applied array-CGH to evaluate six patients carrying cytogenetically detected deletions of the short arm of chromosome 5 who were followed at a genetics community service. The patients' cytogenetic and clinical profiles were reevaluated. A database review was performed to predict additional genes and regulatory elements responsible for the characteristic phenotypic and behavioral traits of this disorder. Array-CGH analysis allowed for delineation of the terminal deletions, which ranged in size from approximately 11.2 Mb to 28.6 Mb, with breakpoints from 5p15.2 to 5p13. An additional dup(8)(p23) (3.5 Mb), considered to be a benign copy number variation, was also observed in one patient. The correlation coefficient value (ρ = 0.13) calculated indicated the presence of a weak relationship between developmental delay and deletion size. Genetic background, family history, epigenetic factors, quantitative trait locus polymorphisms, and environmental factors may also affect patient phenotype and must be taken into account in genotype-phenotype correlations. PMID:27144168

  8. Can human-like Bots control collective mood: agent-based simulations of online chats

    NASA Astrophysics Data System (ADS)

    Tadić, Bosiljka; Šuvakov, Milovan

    2013-10-01

    Using an agent-based modeling approach, in this paper, we study self-organized dynamics of interacting agents in the presence of chat Bots. Different Bots with tunable ‘human-like’ attributes, which exchange emotional messages with agents, are considered, and the collective emotional behavior of agents is quantitatively analyzed. In particular, using detrended fractal analysis we determine persistent fluctuations and temporal correlations in time series of agent activity and statistics of avalanches carrying emotional messages of agents when Bots favoring positive/negative affects are active. We determine the impact of Bots and identify parameters that can modulate that impact. Our analysis suggests that, by these measures, the emotional Bots induce collective emotion among interacting agents by suitably altering the fractal characteristics of the underlying stochastic process. Positive emotion Bots are slightly more effective than negative emotion Bots. Moreover, Bots which periodically alternate between positive and negative emotion can enhance fluctuations in the system, leading to avalanches of agent messages that are reminiscent of self-organized critical states.

  9. Childhood apraxia of speech without intellectual deficit in a patient with cri du chat syndrome.

    PubMed

    Marignier, Stéphanie; Lesca, Gaetan; Marguin, Jessica; Bussy, Gérald; Sanlaville, Damien; des Portes, Vincent

    2012-06-01

    We report an 11-year-old girl for whom the diagnosis of cri du chat syndrome (CdCS) was made during a genetic investigation of childhood apraxia of speech. The patient presented with the classic chromosome 5 short arm deletion found in CdCS. The microdeletion, characterised using aCGH (array Comparative Genomic Hybridisation), was 12.85 Mb, overlapping the 5p15.2 and 5p15.3 critical regions. CdCS is typically associated with severe mental retardation while this patient had normal intellectual performance, confirmed by normal results from categorisation tasks. This mild phenotype was assessed using a comprehensive cognitive battery. Language evaluation showed normal receptive vocabulary scores, in contrast with obvious oro-facial dyspraxia. Disabled fine motor skills were confirmed as well as weak visuo-spatial reasoning abilities. In conclusion, fine cognitive assessment may be worthwhile for patients with CdCS since good intellectual functioning may be masked by severe speech and gestural dyspraxia, thus requiring specific teaching and rehabilitation strategies. PMID:22510527

  10. STS-87 Payload Specialist Leonid Kadenyuk chats with NASA Administrator Daniel Goldin shortly after

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-87 Payload Specialist Leonid Kadenyuk of the National Space Agency of Ukraine (NSAU), at left, chats with NASA Administrator Daniel Goldin shortly after the landing of Columbia at Kennedy Space Center. Looking on is back-up Payload Specialist Yaroslav Pustovyi, also of NSAU. STS-87 concluded its mission with a main gear touchdown at 7:20:04 a.m. EST Dec. 5, at KSC's Shuttle Landing Facility Runway 33, drawing the 15-day, 16-hour and 34- minute-long mission of 6.5 million miles to a close. Also onboard the orbiter were Commander Kevin Kregel; Pilot Steven Lindsey; and Mission Specialists Winston Scott, Kalpana Chawla, Ph.D., and Takao Doi, Ph.D., of the National Space Development Agency of Japan. During the 88th Space Shuttle mission, the crew performed experiments on the United States Microgravity Payload-4 and pollinated plants as part of the Collaborative Ukrainian Experiment. This was the 12th landing for Columbia at KSC and the 41st KSC landing in the history of the Space Shuttle program.

  11. Glutathione S-transferase activity and glutathione S-transferase mu expression in subjects with risk for colorectal cancer.

    PubMed

    Szarka, C E; Pfeiffer, G R; Hum, S T; Everley, L C; Balshem, A M; Moore, D F; Litwin, S; Goosenberg, E B; Frucht, H; Engstrom, P F

    1995-07-01

    The glutathione S-transferases (alpha, mu, and pi), a family of Phase II detoxication enzymes, play a critical role in protecting the colon mucosa by catalyzing the conjugation of dietary carcinogens with glutathione. We investigated the efficacy of using the glutathione S-transferase (GST) activity of blood lymphocytes and GST-mu expression as biomarkers of risk for colorectal cancer. GST activity was measured in the blood lymphocytes of control individuals (n = 67) and in the blood lymphocytes (n = 60) and colon tissue (n = 34) of individuals at increased risk for colon cancer. Total GST activity was determined spectrophotometrically with the use of 1-chloro-2,4-dinitrobenzene as a substrate. The ability to express the um subclass of GST was determined with the use of an ELISA. Although interindividual variability in the GST activity of blood lymphocytes was greater than 8-fold (range, 16.7-146.8 nmol/min/mg), the GST activity of blood lymphocytes and colon tissue within an individual was constant over time and was unrelated to sex, age, or race. The GST activity of blood lymphocytes from high-risk individuals was significantly lower than that of blood lymphocytes from control individuals (P < or = 0.004). No association was observed between the frequency of GST-mu phenotype and risk for colorectal cancer. Blood lymphocytes from high-risk individuals unable to express GST-mu had lower levels of GST activity than did those from control subjects with the GST-mu null phenotype; however, this difference was significant in male subjects only (P < or = 0.006). Analysis of paired samples of blood lymphocytes and colon tissue indicated a strong correlation between the GST activity of the two tissue types (Spearman's rank correlation, r = 0.87; P < or = 0.0001). The GST activity of blood lymphocytes may be used to identify high-risk individuals with decreased protection from this Phase II detoxication enzyme who may benefit from clinical trials evaluating GST modulators

  12. Isolation of a mutant Arabidopsis plant that lacks N-aetyl glucosaminyl transferase I and is unable to synthesize Golgi-modified complex N-linked glycans

    SciTech Connect

    Schaewen, A. von; O'Neill, J.; Chrispeels, M.J. ); Sturm, A. )

    1993-08-01

    The complex asparagine-linked glycans of plant glycoproteins, characterized by the presence of [beta]1[yields]2 xylose and [alpha]1[yields]3 fucose residues, are derived from typical mannose[sub 9](N-acetylglucosamine)[sub 2] (Man[sub 9]GlcNAc[sub 2]) N-linked glycans through the activity of a series of glycosidases and glycosyl transferases in the Golgi apparatus. By screening leaf extracts with an antiserum against complex glycans, we isolated a mutant of Arbidopsis thaliana that is blocked in the conversion of high-manne to complex glycans. In callus tissues derived from the mutant plants, all glycans bind to concanavalin A. These glycans can be released by treatment with endoglycosidase H, and the majority has the same size as Man[sub 5]GlcNAc[sub 1] glycans. In the presence of deoxymannojirimycin, an inhibitor of mannosidase I, the mutant cells synthesize Man[sub 9]GlcNAc[sub 2] and Man[sub 8]GlcNAc[sub 2] glycans, suggesting that the biochemical lesion in the mutant is not in the biosynthesis of high-mannose glycans in the endoplasmic reticulum but in their modification in the Golgi. Direct enzyme assays of cell extracts show that the mutant cells lack N-acetyl glucosaminyl transferase I, the first enzyme in the pathway of complex glycan biosynthesis. The mutant plants are able to complete their development normally under several environmental conditions, suggesting that complex glycans are not essential for normal developmental processes. By crossing the complex-glycan-deficient strain of A. thaliana with a transgenic strain that expresses the glycoprotein phytohemagglutinin, a unique strain was obtained that synthesizes phytohemagglutinin with two high-mannose glycans, instead of one high-mannose and one complex glycan. 42 refs., 8 figs., 1 tab.

  13. Streamflow, Water Quality, and Metal Loads from Chat Leachate and Mine Outflow into Tar Creek, Ottawa County, Oklahoma, 2005

    USGS Publications Warehouse

    Cope, Caleb C.; Becker, Mark F.; Andrews, William J.; DeHay, Kelli

    2008-01-01

    Picher mining district is an abandoned lead and zinc mining area located in Ottawa County, northeastern Oklahoma. During the first half of the 20th century, the area was a primary producer of lead and zinc in the United States. Large accumulations of mine tailings, locally referred to as chat, produce leachate containing cadmium, iron, lead, and zinc that enter drainages within the mining area. Metals also seep to local ground water and streams from unplugged shafts, vent holes, seeps, and abandoned mine dewatering wells. Streamflow measurements were made and water-quality samples were collected and analyzed from two locations in Picher mining district from August 16 to August 29 following a rain event beginning on August 14, 2005, to determine likely concentrations and loads of metals from tailings and mine outflows in the part of Picher mining district near Tar Creek. Locations selected for sampling included a tailings pile with an adjacent mill pond, referred to as the Western location, and a segment of Tar Creek from above the confluence with Lytle Creek to below Douthat bridge, referred to as Tar Creek Study Segment. Measured streamflow was less than 0.01 cubic foot per second at the Western location, with streamflow only being measurable at that site on August 16, 2005. Measured streamflows ranged from <0.01 to 2.62 cubic feet per second at Tar Creek Study Segment. One water-quality sample was collected from runoff at the Western location. Total metals concentrations in that sample were 95.3 micrograms per liter cadmium, 182 micrograms per liter iron, 170 micrograms per liter lead, 1,760 micrograms per liter zinc. Total mean metals concentrations in 29 water-quality samples collected from Tar Creek Study Segment from August 16-29, 2005, were 21.8 micrograms per liter cadmium, 7,924 micrograms per liter iron, 7.68 micrograms per liter lead, and 14,548 micrograms per liter zinc. No metals loading values were calculated for the Western location. Metals loading

  14. Molecular characterization of a new acetyl xylan esterase (AXEII) from edible straw mushroom Volvariella volvacea with both de-O-acetylation and de-N-acetylation activity.

    PubMed

    Liu, Xiufeng; Ding, Shaojun

    2009-06-01

    A new Volvariella volvacea gene encoding a carbohydrate esterase (CE) family 4 acetyl xylan esterase (AXE) (designated as VvaxeII) was cloned and characterized. The coded polypeptide had 253 amino acid residues, with the first 19 serving as a secretion signal peptide. The VvaxeII transcript levels were high when the fungus was grown on oat spelt xylan, cellobiose, microcrystalline cellulose, carboxymethyl-cellulose, lactose, galactose, and chitin from crab as carbon sources. The recombinant VvAXEII produced by expression of VvaxeII in Pichia pastoris exhibited activity toward acetylated oat spelt xylan and various chitinous substrates, but was totally inactive against artificial aromatic acetates such as beta-nitrophenyl, 4-methylumbelliferyl, and alpha-naphthyl acetates. Enzyme-catalyzed hydrolysis was maximal at pH 7.0 and 60 degrees C, and reciprocal plots revealed an apparent K(m) value of 1.42 mg mL(-1) and a V(max) value of 833 IU micromol(-1) protein using glycol chitin as a substrate. The recombinant VvAXEII requires activation by bivalent cations such as Co2+ and Mg2+. Interestingly, the recombinant VvAXEII showed no deacetylation activity to fully acetylated monosaccharides such as xylose tetraacetate. PMID:19473250

  15. Tubulin acetylation: responsible enzymes, biological functions and human diseases.

    PubMed

    Li, Lin; Yang, Xiang-Jiao

    2015-11-01

    Microtubules have important functions ranging from maintenance of cell morphology to subcellular transport, cellular signaling, cell migration, and formation of cell polarity. At the organismal level, microtubules are crucial for various biological processes, such as viral entry, inflammation, immunity, learning and memory in mammals. Microtubules are subject to various covalent modifications. One such modification is tubulin acetylation, which is associated with stable microtubules and conserved from protists to humans. In the past three decades, this reversible modification has been studied extensively. In mammals, its level is mainly governed by opposing actions of α-tubulin acetyltransferase 1 (ATAT1) and histone deacetylase 6 (HDAC6). Knockout studies of the mouse enzymes have yielded new insights into biological functions of tubulin acetylation. Abnormal levels of this modification are linked to neurological disorders, cancer, heart diseases and other pathological conditions, thereby yielding important therapeutic implications. This review summarizes related studies and concludes that tubulin acetylation is important for regulating microtubule architecture and maintaining microtubule integrity. Together with detyrosination, glutamylation and other modifications, tubulin acetylation may form a unique 'language' to regulate microtubule structure and function. PMID:26227334

  16. Mass spectrometry-based detection of protein acetylation

    PubMed Central

    Li, Yu; Silva, Jeffrey C.; Skinner, Mary E.; Lombard, David B.

    2014-01-01

    Summary Improved sample preparation techniques and increasingly sensitive mass spectrometry (MS) analysis have revolutionized the study of protein post-translational modifications (PTMs). Here, we describe a general approach for immunopurification and MS-based identification of acetylated proteins in biological samples. This approach is useful characterizing changes in the acetylome in response to biological interventions (1). PMID:24014401

  17. Prebiotically plausible oligoribonucleotide ligation facilitated by chemoselective acetylation

    NASA Astrophysics Data System (ADS)

    Bowler, Frank R.; Chan, Christopher K. W.; Duffy, Colm D.; Gerland, Béatrice; Islam, Saidul; Powner, Matthew W.; Sutherland, John D.; Xu, Jianfeng

    2013-05-01

    The recent synthesis of pyrimidine ribonucleoside-2‧,3‧-cyclic phosphates under prebiotically plausible conditions has strengthened the case for the involvement of ribonucleic acid (RNA) at an early stage in the origin of life. However, a prebiotic conversion of these weakly activated monomers, and their purine counterparts, to the 3‧,5‧-linked RNA polymers of extant biochemistry has been lacking (previous attempts led only to short oligomers with mixed linkages). Here we show that the 2‧-hydroxyl group of oligoribonucleotide-3‧-phosphates can be chemoselectively acetylated in water under prebiotically credible conditions, which allows rapid and efficient template-directed ligation. The 2‧-O-acetyl group at the ligation junction of the product RNA strand can be removed under conditions that leave the internucleotide bonds intact. Remarkably, acetylation of mixed oligomers that possess either 2‧- or 3‧-terminal phosphates is selective for the 2‧-hydroxyl group of the latter. This newly discovered chemistry thus suggests a prebiotic route from ribonucleoside-2‧,3‧-cyclic phosphates to predominantly 3‧,5‧-linked RNA via partially 2‧-O-acetylated RNA.

  18. Monitoring sterol uptake, acetylation, and export in yeast.

    PubMed

    Choudhary, Vineet; Schneiter, Roger

    2009-01-01

    Sterols are essential lipid components of eukaryotic membranes. They are synthesized in the endoplasmatic reticulum (ER) from where they are efficiently transported to the plasma membrane, which harbors ~90% of the free sterol pool of the cell. The molecular mechanisms that govern this lipid transport, however, are not well characterized and are challenging to analyze. Saccharomyces cerevisiae offers the opportunity to circumvent some of the technical limitations associated with studying this forward transport of sterols from the ER to the plasma membrane, because the organism can also take up sterols from the environment, incorporate them into the plasma membrane and transport them back to the ER, where the free sterol is converted to steryl esters. This reverse sterol transport, however, occurs only under anaerobic conditions, where the cells become sterol auxotroph, or in mutant cells that cannot synthesize heme. The reverse sterol transport pathway, however, is more amenable to experimental studies, because arrival of the sterol in the ER membrane can be monitored unambiguously by following the formation of steryl esters. Apart from sterol acylation, we have recently described a reversible sterol acetylation cycle that is operating in the lumen of the ER. Acetylation occurs on both cholesterol and pregnenolone, a steroid precursor, and serves as a signal for export of the acetylated sterols into the culture media. The time-dependent appearance of acetylated sterols in the culture supernatant thus provides a new means to monitor the forward transport of chemically modified sterols out of the ER. PMID:19784602

  19. Acetylation regulates DNA repair mechanisms in human cells.

    PubMed

    Piekna-Przybylska, Dorota; Bambara, Robert A; Balakrishnan, Lata

    2016-06-01

    The p300-mediated acetylation of enzymes involved in DNA repair and replication has been previously shown to stimulate or inhibit their activities in reconstituted systems. To explore the role of acetylation on DNA repair in cells we constructed plasmid substrates carrying inactivating damages in the EGFP reporter gene, which should be repaired in cells through DNA mismatch repair (MMR) or base excision repair (BER) mechanisms. We analyzed efficiency of repair within these plasmid substrates in cells exposed to deacetylase and acetyltransferase inhibitors, and also in cells deficient in p300 acetyltransferase. Our results indicate that protein acetylation improves DNA mismatch repair in MMR-proficient HeLa cells and also in MMR-deficient HCT116 cells. Moreover, results suggest that stimulated repair of mismatches in MMR-deficient HCT116 cells is done though a strand-displacement synthesis mechanism described previously for Okazaki fragments maturation and also for the EXOI-independent pathway of MMR. Loss of p300 reduced repair of mismatches in MMR-deficient cells, but did not have evident effects on BER mechanisms, including the long patch BER pathway. Hypoacetylation of the cells in the presence of acetyltransferase inhibitor, garcinol generally reduced efficiency of BER of 8-oxoG damage, indicating that some steps in the pathway are stimulated by acetylation. PMID:27104361

  20. An Acetylation Switch Regulates SUMO-Dependent Protein Interaction Networks

    PubMed Central

    Ullmann, Rebecca; Chien, Christopher D.; Avantaggiati, Maria Laura; Muller, Stefan

    2013-01-01

    SUMMARY The attachment of the SUMO modifier to proteins controls cellular signaling pathways through noncovalent binding to SUMO-interaction motifs (SIMs). Canonical SIMs contain a core of hydrophobic residues that bind to a hydrophobic pocket on SUMO. Negatively charged residues of SIMs frequently contribute to binding by interacting with a basic surface on SUMO. Here we define acetylation within this basic interface as a central mechanism for the control of SUMO-mediated interactions. The acetyl-mediated neutralization of basic charges on SUMO prevents binding to SIMs in PML, Daxx, and PIAS family members but does not affect the interaction between RanBP2 and SUMO. Acetylation is controlled by HDACs and attenuates SUMO- and PIAS-mediated gene silencing. Moreover, it affects the assembly of PML nuclear bodies and restrains the recruitment of the corepressor Daxx to these structures. This acetyl-dependent switch thus expands the regulatory repertoire of SUMO signaling and determines the selectivity and dynamics of SUMO-SIM interactions. PMID:22578841

  1. Protein Acetylation Is Involved in Salmonella enterica Serovar Typhimurium Virulence.

    PubMed

    Sang, Yu; Ren, Jie; Ni, Jinjing; Tao, Jing; Lu, Jie; Yao, Yu-Feng

    2016-06-01

    Salmonella causes a range of diseases in different hosts, including enterocolitis and systemic infection. Lysine acetylation regulates many eukaryotic cellular processes, but its function in bacteria is largely unexplored. The acetyltransferase Pat and NAD(+)-dependent deacetylase CobB are involved in the reversible protein acetylation in Salmonella Typhimurium. Here, we used cell and animal models to evaluate the virulence of pat and cobB deletion mutants in S. Typhimurium and found that pat is critical for bacterial intestinal colonization and systemic infection. Next, to understand the underlying mechanism, genome-wide transcriptome was analyzed. RNA sequencing data showed that the expression of Salmonella pathogenicity island 1 (SPI-1) is partially dependent on pat In addition, we found that HilD, a key transcriptional regulator of SPI-1, is a substrate of Pat. The acetylation of HilD by Pat maintained HilD stability and was essential for the transcriptional activation of HilA. Taken together, these results suggest that a protein acetylation system regulates SPI-1 expression by controlling HilD in a posttranslational manner to mediate S. Typhimurium virulence. PMID:26810370

  2. Nucleosome competition reveals processive acetylation by the SAGA HAT module.

    PubMed

    Ringel, Alison E; Cieniewicz, Anne M; Taverna, Sean D; Wolberger, Cynthia

    2015-10-01

    The Spt-Ada-Gcn5 acetyltransferase (SAGA) coactivator complex hyperacetylates histone tails in vivo in a manner that depends upon histone 3 lysine 4 trimethylation (H3K4me3), a histone mark enriched at promoters of actively transcribed genes. SAGA contains a separable subcomplex known as the histone acetyltransferase (HAT) module that contains the HAT, Gcn5, bound to Sgf29, Ada2, and Ada3. Sgf29 contains a tandem Tudor domain that recognizes H3K4me3-containing peptides and is required for histone hyperacetylation in vivo. However, the mechanism by which H3K4me3 recognition leads to lysine hyperacetylation is unknown, as in vitro studies show no effect of the H3K4me3 modification on histone peptide acetylation by Gcn5. To determine how H3K4me3 binding by Sgf29 leads to histone hyperacetylation by Gcn5, we used differential fluorescent labeling of histones to monitor acetylation of individual subpopulations of methylated and unmodified nucleosomes in a mixture. We find that the SAGA HAT module preferentially acetylates H3K4me3 nucleosomes in a mixture containing excess unmodified nucleosomes and that this effect requires the Tudor domain of Sgf29. The H3K4me3 mark promotes processive, multisite acetylation of histone H3 by Gcn5 that can account for the different acetylation patterns established by SAGA at promoters versus coding regions. Our results establish a model for Sgf29 function at gene promoters and define a mechanism governing crosstalk between histone modifications. PMID:26401015

  3. Mechanism for the Inhibition of the Carboxyl-transferase

    SciTech Connect

    L Yu; Y Kim; L Tong

    2011-12-31

    Acetyl-CoA carboxylases (ACCs) are crucial metabolic enzymes and have been targeted for drug development against obesity, diabetes, and other diseases. The carboxyltransferase (CT) domain of this enzyme is the site of action for three different classes of herbicides, as represented by haloxyfop, tepraloxydim, and pinoxaden. Our earlier studies have demonstrated that haloxyfop and tepraloxydim bind in the CT active site at the interface of its dimer. However, the two compounds probe distinct regions of the dimer interface, sharing primarily only two common anchoring points of interaction with the enzyme. We report here the crystal structure of the CT domain of yeast ACC in complex with pinoxaden at 2.8-{angstrom} resolution. Despite their chemical diversity, pinoxaden has a similar binding mode as tepraloxydim and requires a small conformational change in the dimer interface for binding. Crystal structures of the CT domain in complex with all three classes of herbicides confirm the importance of the two anchoring points for herbicide binding. The structures also provide a foundation for understanding the molecular basis of the herbicide resistance mutations and cross resistance among the herbicides, as well as for the design and development of new inhibitors against plant and human ACCs.

  4. Protective effects of Eugenia jambolana extract versus N-acetyl cysteine against cisplatin-induced damage in rat testis.

    PubMed

    Anand, H; Misro, M M; Sharma, S B; Prakash, S

    2015-03-01

    To assess the protective effects of Eugenia jambolana extract (EJE) or N-acetyl cysteine (NAC) on testis, cisplatin (CIS, 5 mg kg(-1) bw, single dose) was administered either alone or along with EJE (25 mg kg(-1) bw, alternate day) or NAC (150 mg kg(-1) bw, Day 1 and 4) for 7 days. Significant alterations in serum LH, FSH and testosterone were observed in CIS group which were effectively modulated by EJE or NAC supplementation. Upregulation of 3β-HSD gene indicated the rise in functional Leydig cells. This was further confirmed from the identical improvement in hCG-stimulated testosterone production in isolated Leydig cells. Reduction in oxidative stress was associated with restoration of total antioxidant capacity and glutathione levels, and activation of antioxidant enzymes, SOD, catalase, glutathione s-transferase (GST) and glutathione reductase (GR). CIS-induced apoptosis of germ and Leydig cells was contained by both NAC and EJE intervention by effective modulation of apoptotic markers in the extrinsic, intrinsic and other pathways of metazoan apoptosis. Taken together, the study findings establish the potential of EJE as a therapeutically better antioxidant than NAC for use in curtailing the adverse effects of anticancer drugs on testicular function. PMID:24576220

  5. Analysis of Arabidopsis glutathione-transferases in yeast.

    PubMed

    Krajewski, Matthias P; Kanawati, Basem; Fekete, Agnes; Kowalski, Natalie; Schmitt-Kopplin, Philippe; Grill, Erwin

    2013-07-01

    The genome of Arabidopsis thaliana encodes 54 functional glutathione transferases (GSTs), classified in seven clades. Although plant GSTs have been implicated in the detoxification of xenobiotics, such as herbicides, extensive redundancy within this large gene family impedes a functional analysis in planta. In this study, a GST-deficient yeast strain was established as a system for analyzing plant GSTs that allows screening for GST substrates and identifying substrate preferences within the plant GST family. To this end, five yeast genes encoding GSTs and GST-related proteins were simultaneously disrupted. The resulting yeast quintuple mutant showed a strongly reduced conjugation of the GST substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl). Consistently, the quintuple mutant was hypersensitive to CDNB, and this phenotype was complemented by the inducible expression of Arabidopsis GSTs. The conjugating activity of the plant GSTs was assessed by in vitro enzymatic assays and via analysis of exposed yeast cells. The formation of glutathione adducts with dinitrobenzene was unequivocally verified by stable isotope labeling and subsequent accurate ultrahigh-resolution mass spectrometry (ICR-FTMS). Analysis of Arabidopsis GSTs encompassing six clades and 42 members demonstrated functional expression in yeast by using CDNB and NBD-Cl as model substrates. Subsequently, the established yeast system was explored for its potential to screen the Arabidopsis GST family for conjugation of the fungicide anilazine. Thirty Arabidopsis GSTs were identified that conferred increased levels of glutathionylated anilazine. Efficient anilazine conjugation was observed in the presence of the phi, tau, and theta clade GSTs including AtGSTF2, AtGSTF4, AtGSTF6, AtGSTF8, AtGSTF10, and AtGSTT2, none of which had previously been known to contribute to fungicide detoxification. ICR-FTMS analysis of yeast extracts allowed the simultaneous detection and

  6. Selection of antisense oligodeoxynucleotides against glutathione S-transferase Mu.

    PubMed Central

    't Hoen, Peter A C; Out, Ruud; Commandeur, Jan N M; Vermeulen, Nico P E; van Batenburg, F H D; Manoharan, Muthiah; van Berkel, Theo J C; Biessen, Erik A L; Bijsterbosch, Martin K

    2002-01-01

    The aim of the present study was to identify functional antisense oligodeoxynucleotides (ODNs) against the rat glutathione S-transferase Mu (GSTM) isoforms, GSTM1 and GSTM2. These antisense ODNs would enable the study of the physiological consequences of GSTM deficiency. Because it has been suggested that the effectiveness of antisense ODNs is dependent on the secondary mRNA structures of their target sites, we made mRNA secondary structure predictions with two software packages, Mfold and STAR. The two programs produced only marginally similar structures, which can probably be attributed to differences in the algorithms used. The effectiveness of a set of 18 antisense ODNs was evaluated with a cell-free transcription/translation assay, and their activity was correlated with the predicted secondary RNA structures. Four phosphodiester ODNs specific for GSTM1, two ODNs specific for GSTM2, and four ODNs targeted at both GSTM isoforms were found to be potent, sequence-specific, and RNase H-dependent inhibitors of protein expression. The IC50 value of the most potent ODN was approximately 100 nM. Antisense ODNs targeted against regions that were predicted by STAR to be predominantly single stranded were more potent than antisense ODNs against double-stranded regions. Such a correlation was not found for the Mfold prediction. Our data suggest that simulation of the local folding of RNA facilitates the discovery of potent antisense sequences. In conclusion, we selected several promising antisense sequences, which, when synthesized as biologically stable oligonucleotides, can be applied for study of the physiological impact of reduced GSTM expression. PMID:12515389

  7. Phosphonocarboxylates Inhibit the Second Geranylgeranyl Addition by Rab Geranylgeranyl Transferase*

    PubMed Central

    Baron, Rudi A.; Tavaré, Richard; Figueiredo, Ana C.; Błażewska, Katarzyna M.; Kashemirov, Boris A.; McKenna, Charles E.; Ebetino, Frank H.; Taylor, Adam; Rogers, Michael J.; Coxon, Fraser P.; Seabra, Miguel C.

    2009-01-01

    Rab geranylgeranyl transferase (RGGT) catalyzes the post-translational geranylgeranyl (GG) modification of (usually) two C-terminal cysteines in Rab GTPases. Here we studied the mechanism of the Rab geranylgeranylation reaction by bisphosphonate analogs in which one phosphonate group is replaced by a carboxylate (phosphonocarboxylate, PC). The phosphonocarboxylates used were 3-PEHPC, which was previously reported, and 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid ((+)-3-IPEHPC), a >25-fold more potent related compound as measured by both IC50 and Ki.(+)-3-IPEHPC behaves as a mixed-type inhibitor with respect to GG pyrophosphate (GGPP) and an uncompetitive inhibitor with respect to Rab substrates. We propose that phosphonocarboxylates prevent only the second GG transfer onto Rabs based on the following evidence. First, geranylgeranylation of Rab proteins ending with a single cysteine motif such as CAAX, is not affected by the inhibitors, either in vitro or in vivo. Second, the addition of an -AAX sequence onto Rab-CC proteins protects the substrate from inhibition by the inhibitors. Third, we demonstrate directly that in the presence of (+)-3-IPEHPC, Rab-CC and Rab-CXC proteins are modified by only a single GG addition. The presence of (+)-3-IPEHPC resulted in a preference for the Rab N-terminal cysteine to be modified first, suggesting an order of cysteine geranylgeranylation in RGGT catalysis. Our results further suggest that the inhibitor binds to a site distinct from the GGPP-binding site on RGGT. We suggest that phosphonocarboxylate inhibitors bind to a GG-cysteine binding site adjacent to the active site, which is necessary to align the mono-GG-Rab for the second GG addition. These inhibitors may represent a novel therapeutic approach in Rab-mediated diseases. PMID:19074143

  8. The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-induced Lysine Acetylation of Mitochondrial Proteins

    PubMed Central

    Davies, Michael N.; Kjalarsdottir, Lilja; Thompson, J. Will; Dubois, Laura G.; Stevens, Robert D.; Ilkayeva, Olga R.; Brosnan, M. Julia; Rolph, Timothy P.; Grimsrud, Paul A.; Muoio, Deborah M.

    2016-01-01

    Lysine acetylation (AcK), a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT), an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK. PMID:26748706

  9. ESAT and M-CHAT as screening instruments for autism spectrum disorders at 18 months in the general population: issues of overlap and association with clinical referrals.

    PubMed

    Beuker, Karin T; Schjølberg, Synnve; Lie, Kari Kveim; Swinkels, Sophie; Rommelse, Nanda N J; Buitelaar, Jan K

    2014-11-01

    The Modified Checklist for Autism in Toddlers (M-CHAT) and the Early Screening of Autistic Traits (ESAT) were designed to screen for autism spectrum disorders in very young children. The aim of this study was to explore proportions of children that screened positive on the ESAT or the M-CHAT and to investigate if screening positive on the ESAT and M-CHAT is associated with clinical referral by 18 months and other aspects of children's development, health, and behavior. In this study, the mothers of 12,948 18-month-old children returned a questionnaire consisting of items from the ESAT and M-CHAT, plus questions about clinical and developmental characteristics. The M-CHAT identified more screen-positive children than the ESAT, but the ESAT was associated with more clinical referrals and tended to identify more children with medical, language, and behavioral problems. A post hoc analysis of combining the two instruments found this to be more effective than the individual instruments alone in identifying children referred to clinical services at 18 months. Further analysis at the level of single items is warranted to improve these screening instruments. PMID:24867341

  10. Complex O-acetylation in non-typeable Haemophilus influenzae lipopolysaccharide: evidence for a novel site of O-acetylation.

    PubMed

    Yildirim, Håkan H; Li, Jianjun; Richards, James C; Hood, Derek W; Moxon, E Richard; Schweda, Elke K H

    2005-12-12

    The structure of the lipopolysaccharide (LPS) of non-typeable Haemophilus influenzae strain 723 has been elucidated using NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS) on O-deacylated LPS and core oligosaccharide material (OS), as well as ESI-MSn on permethylated dephosphorylated OS. It was found that the LPS contains the common structural element of H. influenzae, l-alpha-D-Hepp-(1-->2)-[PEtn-->6]-l-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-l-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdo-(2-->6)-Lipid A, in which the beta-D-Glcp residue (GlcI) is substituted by phosphocholine at O-6 and the distal heptose residue (HepIII) by PEtn at O-3, respectively. In a subpopulation of glycoforms O-2 of HepIII was substituted by beta-D-Galp-(1-->4)-beta-D-Glcp-(1--> or beta-D-Glcp-(1-->. Considerable heterogeneity of the LPS was due to the extent of substitution by O-acetyl groups (Ac) and ester-linked glycine of the core oligosaccharide. The location for glycine was found to be at Kdo. Prominent acetylation sites were found to be at GlcI, HepIII, and the proximal heptose (HepI) residue of the triheptosyl moiety. Moreover, GlcI was acetylated at O-3 and/or O-4 and HepI was acetylated at O-2 as evidenced by capillary electrophoresis ESI-MSn in combination with NMR analyses. This is the first study to show that an acetyl group can substitute HepI of the inner-core region of H. influenzae LPS. PMID:16199021

  11. Narrative discourse and sociocognitive abilities of a child with Cri-du-Chat syndrome.

    PubMed

    Albano, Stefania; Piccardi, Laura; Pizzamiglio, Maria Rosa; Volpe, Cristino; D'Amico, Simonetta

    2013-01-01

    The authors investigated narrative competence, sociocognitive abilities and emotion comprehension in a 9-year-old child (FS) with Cri-du-Chat Syndrome (CdCS) who had only a mild mental delay and relatively preserved language. Considering that the production of narratives is a major step in development and in the acquisition of learning skills related to conceptual, linguistic, structural, and pragmatic knowledge, and in the development of psychological lexicon, that is, the ability to use theory of mind (ToM) processes also in atypical development, this case provided an opportunity to study aspects of this genetic syndrome never investigated before. The authors found that the child's performance on different stories was comparable to that of chronological age controls for several narrative and emotional competences and even better than that of mental age controls. However, her ability to reason was still incomplete according ToM; in fact, FS was able to express her mental states, but she was unable to understand emotions, specifically mixed emotions. This finding suggests that in CdCS children with a well-developed language narrative and emotional competence could be a point of strength for improving their social skills with important effects on their familiar and school life. Also in CdCS children with the typical poor developed language, the narrative discourse could be introduced in their communication by means of any type of alternative language (i.e., sign language or augmentative and alternative communication) to improve their social abilities and to reduce behavioral disorders due to the difficulty in expressing their personal experiences. PMID:23534097

  12. Altered acetylation and succinylation profiles in Corynebacterium glutamicum in response to conditions inducing glutamate overproduction.

    PubMed

    Mizuno, Yuta; Nagano-Shoji, Megumi; Kubo, Shosei; Kawamura, Yumi; Yoshida, Ayako; Kawasaki, Hisashi; Nishiyama, Makoto; Yoshida, Minoru; Kosono, Saori

    2016-02-01

    The bacterium Corynebacterium glutamicum is utilized during industrial fermentation to produce amino acids such as L-glutamate. During L-glutamate fermentation, C. glutamicum changes the flux of central carbon metabolism to favor L-glutamate production, but the molecular mechanisms that explain these flux changes remain largely unknown. Here, we found that the profiles of two major lysine acyl modifications were significantly altered upon glutamate overproduction in C. glutamicum; acetylation decreased, whereas succinylation increased. A label-free semi-quantitative proteomic analysis identified 604 acetylated proteins with 1328 unique acetylation sites and 288 succinylated proteins with 651 unique succinylation sites. Acetylation and succinylation targeted enzymes in central carbon metabolic pathways that are directly related to glutamate production, including the 2-oxoglutarate dehydrogenase complex (ODHC), a key enzyme regulating glutamate overproduction. Structural mapping revealed that several critical lysine residues in the ODHC components were susceptible to acetylation and succinylation. Furthermore, induction of glutamate production was associated with changes in the extent of acetylation and succinylation of lysine, suggesting that these modifications may affect the activity of enzymes involved in glutamate production. Deletion of phosphotransacetylase decreased the extent of protein acetylation in nonproducing condition, suggesting that acetyl phosphate-dependent acetylation is active in C. glutamicum. However, no effect was observed on the profiles of acetylation and succinylation in glutamate-producing condition upon disruption of acetyl phosphate metabolism or deacetylase homologs. It was considered likely that the reduced acetylation in glutamate-producing condition may reflect metabolic states where the flux through acid-producing pathways is very low, and substrates for acetylation do not accumulate in the cell. Succinylation would occur more

  13. Role of Carnitine Acetyltransferases in Acetyl Coenzyme A Metabolism in Aspergillus nidulans ▿

    PubMed Central

    Hynes, Michael J.; Murray, Sandra L.; Andrianopoulos, Alex; Davis, Meryl A.

    2011-01-01

    The flow of carbon metabolites between cellular compartments is an essential feature of fungal metabolism. During growth on ethanol, acetate, or fatty acids, acetyl units must enter the mitochondrion for metabolism via the tricarboxylic acid cycle, and acetyl coenzyme A (acetyl-CoA) in the cytoplasm is essential for the biosynthetic reactions and for protein acetylation. Acetyl-CoA is produced in the cytoplasm by acetyl-CoA synthetase during growth on acetate and ethanol while β-oxidation of fatty acids generates acetyl-CoA in peroxisomes. The acetyl-carnitine shuttle in which acetyl-CoA is reversibly converted to acetyl-carnitine by carnitine acetyltransferase (CAT) enzymes is important for intracellular transport of acetyl units. In the filamentous ascomycete Aspergillus nidulans, a cytoplasmic CAT, encoded by facC, is essential for growth on sources of cytoplasmic acetyl-CoA while a second CAT, encoded by the acuJ gene, is essential for growth on fatty acids as well as acetate. We have shown that AcuJ contains an N-terminal mitochondrial targeting sequence and a C-terminal peroxisomal targeting sequence (PTS) and is localized to both peroxisomes and mitochondria, independent of the carbon source. Mislocalization of AcuJ to the cytoplasm does not result in loss of growth on acetate but prevents growth on fatty acids. Therefore, while mitochondrial AcuJ is essential for the transfer of acetyl units to mitochondria, peroxisomal localization is required only for transfer from peroxisomes to mitochondria. Peroxisomal AcuJ was not required for the import of acetyl-CoA into peroxisomes for conversion to malate by malate synthase (MLS), and export of acetyl-CoA from peroxisomes to the cytoplasm was found to be independent of FacC when MLS was mislocalized to the cytoplasm. PMID:21296915

  14. Histone H3 acetylation in the postmortem Parkinson's disease primary motor cortex.

    PubMed

    Gebremedhin, Kibrom G; Rademacher, David J

    2016-08-01

    Although the role of epigenetics in Parkinson's disease (PD) has not been extensively studied, α-synuclein, the main component of Lewy bodies, decreased histone H3 acetylation. Here, we determined if there were histone acetylation changes in the primary motor cortex which, according to the Braak model, is one of the last brain regions affected in PD. Net histone H3 acetylation, histone H3 lysine 9 (H3K9), histone H3 lysine 14 (H3K14), histone H3 lysine 18 (H3K18), and histone H3 lysine 23 (H3K23) acetylation was assessed in the primary motor cortex of those affected and unaffected by PD. There was net increase in histone H3 acetylation due to increased H3K14 and H3K18 acetylation. There was a decrease in H3K9 acetylation. No between-groups difference was detected in H3K23 acetylation. Relationships between Unified Lewy Body Staging scores and histone H3 acetylation and substantia nigra depigmentation scores and histone H3 acetylation were observed. No relationships were detected between postmortem interval and histone H3 acetylation and expired age and histone H3 acetylation. These correlational data support the notion that the histone H3 acetylation changes observed here are not due to the postmortem interval or aging. Instead, they are due to PD and/or factors that covary with PD. The data suggest enhanced gene transcription in the primary motor cortex of the PD brain due to increase H3K14 and H3K18 acetylation. This effect is partially offset by a decreased H3K9 acetylation, which might repress gene transcription. PMID:27241718

  15. Astrocyte Reactivity Following Blast Exposure Involves Aberrant Histone Acetylation

    PubMed Central

    Bailey, Zachary S.; Grinter, Michael B.; VandeVord, Pamela J.

    2016-01-01

    Blast induced neurotrauma (BINT) is a prevalent injury within military and civilian populations. The injury is characterized by persistent inflammation at the cellular level which manifests as a multitude of cognitive and functional impairments. Epigenetic regulation of transcription offers an important control mechanism for gene expression and cellular function which may underlie chronic inflammation and result in neurodegeneration. We hypothesize that altered histone acetylation patterns may be involved in blast induced inflammation and the chronic activation of glial cells. This study aimed to elucidate changes to histone acetylation occurring following injury and the roles these changes may have within the pathology. Sprague Dawley rats were subjected to either a 10 or 17 psi blast overpressure within an Advanced Blast Simulator (ABS). Sham animals underwent the same procedures without blast exposure. Memory impairments were measured using the Novel Object Recognition (NOR) test at 2 and 7 days post-injury. Tissues were collected at 7 days for Western blot and immunohistochemistry (IHC) analysis. Sham animals showed intact memory at each time point. The novel object discrimination decreased significantly between two and 7 days for each injury group (p < 0.05). This is indicative of the onset of memory impairment. Western blot analysis showed glial fibrillary acidic protein (GFAP), a known marker of activated astrocytes, was elevated in the prefrontal cortex (PFC) following blast exposure for both injury groups. Analysis of histone protein extract showed no changes in the level of any total histone proteins within the PFC. However, acetylation levels of histone H2b, H3, and H4 were decreased in both groups (p < 0.05). Co-localization immunofluorescence was used to further investigate any potential correlation between decreased histone acetylation and astrocyte activation. These experiments showed a similar decrease in H3 acetylation in astrocytes exposed to a 17

  16. CHAT: development and validation of a computer-delivered, self-report, substance use assessment for adolescents.

    PubMed

    Lord, Sarah E; Trudeau, Kimberlee J; Black, Ryan A; Lorin, Lucy; Cooney, Elizabeth; Villapiano, Albert; Butler, Stephen F

    2011-01-01

    The current study was conducted to construct and validate a computer-delivered, multimedia, substance use self-assessment for adolescents. Reliability and validity of six problem dimensions were evaluated in two studies, conducted from 2003 to 2008. Study 1 included 192 adolescents from five treatment settings throughout the United States (N = 142) and two high schools from Greater Boston, Massachusetts (N = 50). Study 2 included 356 adolescents (treatment: N = 260; school: N = 94). The final version of Comprehensive Health Assessment for Teens (CHAT) demonstrated relatively strong psychometric properties. The limitations and implications of this study are noted. This study was supported by an SBIR grant. PMID:21174498

  17. Multiple Mass Isotopomer Tracing of Acetyl-CoA Metabolism in Langendorff-perfused Rat Hearts

    PubMed Central

    Li, Qingling; Deng, Shuang; Ibarra, Rafael A.; Anderson, Vernon E.; Brunengraber, Henri; Zhang, Guo-Fang

    2015-01-01

    We developed an isotopic technique to assess mitochondrial acetyl-CoA turnover (≈citric acid flux) in perfused rat hearts. Hearts are perfused with buffer containing tracer [13C2,2H3]acetate, which forms M5 + M4 + M3 acetyl-CoA. The buffer may also contain one or two labeled substrates, which generate M2 acetyl-CoA (e.g. [13C6]glucose or [1,2-13C2]palmitate) or/and M1 acetyl-CoA (e.g. [1-13C]octanoate). The total acetyl-CoA turnover and the contributions of fuels to acetyl-CoA are calculated from the uptake of the acetate tracer and the mass isotopomer distribution of acetyl-CoA. The method was applied to measurements of acetyl-CoA turnover under different conditions (glucose ± palmitate ± insulin ± dichloroacetate). The data revealed (i) substrate cycling between glycogen and glucose-6-P and between glucose-6-P and triose phosphates, (ii) the release of small excess acetyl groups as acetylcarnitine and ketone bodies, and (iii) the channeling of mitochondrial acetyl-CoA from pyruvate dehydrogenase to carnitine acetyltransferase. Because of this channeling, the labeling of acetylcarnitine and ketone bodies released by the heart are not proxies of the labeling of mitochondrial acetyl-CoA. PMID:25645937

  18. An exploratory study of Internet-initiated sexual offenses and the chat room sex offender: has the Internet enabled a new typology of sex offender?

    PubMed

    Briggs, Peter; Simon, Walter T; Simonsen, Stacy

    2011-03-01

    This exploratory study examined 51 participants convicted of an Internet-initiated sex offense in which they attempted to entice an adolescent into a sexual relationship using an Internet chat room. All participants were convicted of a sex offense and subject to an evaluation as a part of sentencing requirements in Colorado. Clinical and behavioral data were obtained from each subject's offense-specific evaluation and chat room transcripts. The results of the study found that 90% of the participants were apprehended as a result of an Internet sex sting. The authors conclude that Internet chat room sex offenders constitute a separate group characterized by less severe criminogenic factors than other sex offenders (rapists, child molesters). It can be hypothesized that chat room sex offenders avoid relationships and spend a significant amount of time in online chat rooms as a primary social and sexual outlet, and engage in other sexually compulsive behaviors. Within this offender group, it was discovered that two subgroups exist: a contact-driven group motivated to engage in offline sexual behavior with an adolescent and a fantasy-driven group motivated to engage an adolescent in online cybersex without an express intent to meet offline. The chat room sex offender presents a significant clinical issue to treatment providers as a live victim does not exist. Thus, it is unclear if Internet sex stings prevent incidents of child sexual exploitation and may result in convictions of individuals who may never have abused a child. The data suggest a tentative sex offender typology, including subtypes, which need to be replicated in future studies. PMID:20947699

  19. Crystallization and preliminary X-ray crystallographic analysis of UDP-N-acetylglucosamine enolpyruvyl transferase from Haemophilus influenzae in complex with UDP-N-acetylglucosamine and fosfomycin.

    PubMed

    Yoon, Hye-Jin; Ku, Min-Je; Ahn, Hyung Jun; Lee, Byung Il; Mikami, Bunzo; Suh, Se Won

    2005-06-30

    The bacterial enzyme UDP-N-acetylglucosamine enolpyruvyl transferase catalyzes the first committed step of peptidoglycan biosynthesis, i.e., transfer of enolpyruvate from phosphoenolpyruvate to UDP-N-acetyl-glucosamine. We have overexpressed the enzyme from Haemophilus influenzae in Escherichia coli and crystallized it in the apo-form, as well as in a complex with UDP-N-acetylglucosamine and fosfomycin using ammonium sulfate as the precipitant. X-ray diffraction data from a crystal of the apo-form were collected to 2.8 A resolution at 293 K. The crystal quality was improved by co-crystallization with UDP-N-acetylglucosamine and fosfomycin. X-ray data to 2.2 A have been collected at 100 K from a flash-frozen crystal of the complex. The complex crystals belong to the orthorhombic space group I222 (or I212121) with unit-cell parameters of a = 63.7, b = 124.5, and c = 126.3 A. Assuming a monomer of the recombinant enzyme in the crystallographic asymmetric unit, the calculated Matthews parameter (VM) is 2.71 A3 Da-1 and solvent content is 54.6%. PMID:15995357

  20. [Spectrophotometric evaluation of N-acetyl-beta-glucosaminidase in urine].

    PubMed

    Potere, C; Di Cosmo, C; Riario-Sforza, G; Di Silverio, F; Albertazzi, A; Cappelli, P

    1982-01-01

    A spectrophotometric method for the assay of N-Acetyl-beta-Glucosaminidase activity in human undiluted urines is described. The application of this method is recommended for its sensitivity (2,6 X 10(-4)M) and its rapid performance, because it represents a good alternative to current methods and essentially to the fluorimetric technique with which it has a significant statistical correlation. Estimates of normal individuals aged between 1-70 years are reported. PMID:7168631

  1. Mechanism of action of clostridial glycine reductase: Isolation and characterization of a covalent acetyl enzyme intermediate

    SciTech Connect

    Arkowitz, R.A.; Abeles, R.H. )

    1991-04-23

    Clostridial glycine reductase consists of proteins A, B, and C and catalyzes the reaction glycine + P{sub i} + 2e{sup {minus}} {yields} acetyl phosphate + NH{sub 4}{sup +}. Evidence was previously obtained that is consistent with the involvement of an acyl enzyme intermediate in this reaction. The authors now demonstrate that protein C catalyzes exchange of ({sup 32}P)P{sub i} into acetyl phosphate, providing additional support for an acetyl enzyme intermediate on protein C. Furthermore, they have isolated acetyl protein C and shown that it is qualitatively, catalytically competent. Acetyl protein C can be obtained through the forward reaction from protein C and Se-(carboxymethyl)selenocysteine-protein A, which is generated by the reaction of glycine with proteins A and B. Acetyl protein C can also be generated through the reverse reaction by the addition of acetyl phosphate to protein C. Both procedures lead to the same acetyl enzyme. The acetyl enzyme reacts with P{sub i} to give acetyl phosphate. When ({sup 14}C)acetyl protein C is denaturated with TCA and redissolved with urea, radioactivity remained associated with the protein. Treatment with KBH{sub 4} removes all the radioactivity associated with protein C, resulting in the formation of ({sup 14}C)ethanol. They conclude that a thiol group on protein C is acetylated. Proteins A and C together catalyze the exchange of tritium atoms from ({sup 3}H)H{sub 2}O into acetyl phosphate. This exchange reaction supports the proposal that an enol of the acetyl enzyme is an intermediate in the reaction sequence.

  2. N-Acetyl-4-aminophenol (paracetamol), N-acetyl-2-aminophenol and acetanilide in urine samples from the general population, individuals exposed to aniline and paracetamol users.

    PubMed

    Dierkes, Georg; Weiss, Tobias; Modick, Hendrik; Käfferlein, Heiko Udo; Brüning, Thomas; Koch, Holger M

    2014-01-01

    Epidemiological studies suggest associations between the use of N-acetyl-4-aminophenol (paracetamol) during pregnancy and increased risks of reproductive disorders in the male offspring. Previously we have reported a ubiquitous urinary excretion of N-acetyl-4-aminophenol in the general population. Possible sources are (1) direct intake of paracetamol through medication, (2) paracetamol residues in the food chain and (3) environmental exposure to aniline or related substances that are metabolized into N-acetyl-4-aminophenol. In order to elucidate the origins of the excretion of N-acetyl-4-aminophenol in urine and to contribute to the understanding of paracetamol and aniline metabolism in humans we developed a rapid, turbulent-flow HPLC-MS/MS method with isotope dilution for the simultaneous quantification of N-acetyl-4-aminophenol and two other aniline related metabolites, N-acetyl-2-aminophenol and acetanilide. We applied this method to three sets of urine samples: (1) individuals with no known exposure to aniline and also no recent paracetamol medication; (2) individuals after occupational exposure to aniline but no paracetamol medication and (3) paracetamol users. We confirmed the omnipresent excretion of N-acetyl-4-aminophenol. Additionally we revealed an omnipresent excretion of N-acetyl-2-aminophenol. In contrast, acetanilide was only found after occupational exposure to aniline, not in the general population or after paracetamol use. The results lead to four preliminary conclusions: (1) other sources than aniline seem to be responsible for the major part of urinary N-acetyl-4-aminophenol in the general population; (2) acetanilide is a metabolite of aniline in man and a valuable biomarker for aniline in occupational settings; (3) aniline baseline levels in the general population measured after chemical hydrolysis do not seem to originate from acetanilide and hence not from a direct exposure to aniline itself and (4) N-acetyl-2-aminophenol does not seem to be

  3. Characterization of prenyl protein transferase enzymes in a human keratinocyte cell line.

    PubMed

    MacNulty, E E; Ryder, N S

    1996-02-01

    Prenylation is a post-translational modification of proteins that involves the attachment of an isoprenoid group derived from mevalonic acid, either 15-carbon farnesyl or 20-carbon geranylgeranyl, to a specific carboxy-terminal domain of acceptor proteins. Three prenyl transferase enzymes have been identified so far. In this paper we report the presence of two prenyl transferases in the HaCaT human keratinocyte cell line. Chromatography of a cytosolic extract from these cells resolved a farnesyl protein transferase (FPT) and geranylgeranyl protein transferase-I (GGPT-I) whose activities were measured using a novel peptide-based assay. Both enzymes were inhibited dose dependently by zaragozic acids A and C. Zaragozic acid C was more active towards the FPT than GGPT-I while zaragozic acid A inhibited both enzymes with similar potency. Incubation of HaCaT cell homogenates with [3H] prenyl precursors resulted in the labelling of a number of proteins which was increased when the cells were pretreated with an inhibitor of hydroxymethylglutaryl CoA reductase. Given the role of prenylated proteins in proliferative and inflammatory processes, our finding that prenyl transferases capable of prenylating endogenous substrates are also present in keratinocytes suggests that these enzymes might provide novel therapeutic targets of dermatological importance. PMID:8605230

  4. Combined effect of smoking and inherited polymorphisms in arylamine N-acetyltransferase 2, glutathione S-transferases M1 and T1 on bladder cancer in a Tunisian population.

    PubMed

    Rouissi, Kamel; Ouerhani, Slah; Marrakchi, Raja; Ben Slama, Mohamed R; Sfaxi, Mohamed; Ayed, Mohsen; Chebil, Mohamed; El Gaaied, Amel Benammar

    2009-04-15

    Cigarette smoking is the predominant risk factor for bladder cancer in males and females. The tobacco carcinogens are metabolized by various xenobiotic metabolizing enzymes, such as the super-families of N-acetyltransferases (NAT) and glutathione S-transferases (GST). Polymorphisms in NAT and GST genes alter the ability of these enzymes to metabolize carcinogens. We have conducted this case-control study to assess the role of smoking, slow NAT2 variants, and GSTM1 and GSTT1 null genotypes in bladder cancer development in North Tunisia. In all groups of patients, we have shown that GSTM1 and GSTT1 null genotypes did not appear to be a factor affecting bladder cancer susceptibility. For the NAT2 slow acetylator genotype, the NAT2*5/*7 diplotype was found to have a 7-fold increased risk of bladder (OR=7.14; 95% CI: 1.30-51.41). Furthermore, we found that NAT2 slow acetylator individuals temporarily carrying wild-type GSTT1 or GSTM1 null genotypes have a strong increased risk of bladder cancer (OR= 26 and 22.17, respectively). This cumulative effect was estimated at 12 for smokers harboring slow or an intermediate NAT2, GSTM1 null, and wild-type GSTT1 genotypes compared to non-smokers carrying rapid NAT2, wild-type GSTM,1 and GSTT1 null genotypes (p=0.02; OR=12; CI 95% 1-323.76). PMID:19380028

  5. Acetylation modification regulates GRP78 secretion in colon cancer cells

    PubMed Central

    Li, Zongwei; Zhuang, Ming; Zhang, Lichao; Zheng, Xingnan; Yang, Peng; Li, Zhuoyu

    2016-01-01

    High glucose-regulated protein 78 (GRP78) expression contributes to the acquisition of a wide range of phenotypic cancer hallmarks, and the pleiotropic oncogenic functions of GRP78 may result from its diverse subcellular distribution. Interestingly, GRP78 has been reported to be secreted from solid tumour cells, participating in cell-cell communication in the tumour microenvironment. However, the mechanism underlying this secretion remains elusive. Here, we report that GRP78 is secreted from colon cancer cells via exosomes. Histone deacetylase (HDAC) inhibitors blocked GRP78 release by inducing its aggregation in the ER. Mechanistically, HDAC inhibitor treatment suppressed HDAC6 activity and led to increased GRP78 acetylation; acetylated GRP78 then bound to VPS34, a class III phosphoinositide-3 kinase, consequently preventing the sorting of GRP78 into multivesicular bodies (MVBs). Of note, we found that mimicking GRP78 acetylation by substituting the lysine at residue 633, one of the deacetylated sites of HDAC6, with a glutamine resulted in decreased GRP78 secretion and impaired tumour cell growth in vitro. Our study thus reveals a hitherto-unknown mechanism of GRP78 secretion and may also provide implications for the therapeutic use of HDAC inhibitors. PMID:27460191

  6. Acetylation modification regulates GRP78 secretion in colon cancer cells.

    PubMed

    Li, Zongwei; Zhuang, Ming; Zhang, Lichao; Zheng, Xingnan; Yang, Peng; Li, Zhuoyu

    2016-01-01

    High glucose-regulated protein 78 (GRP78) expression contributes to the acquisition of a wide range of phenotypic cancer hallmarks, and the pleiotropic oncogenic functions of GRP78 may result from its diverse subcellular distribution. Interestingly, GRP78 has been reported to be secreted from solid tumour cells, participating in cell-cell communication in the tumour microenvironment. However, the mechanism underlying this secretion remains elusive. Here, we report that GRP78 is secreted from colon cancer cells via exosomes. Histone deacetylase (HDAC) inhibitors blocked GRP78 release by inducing its aggregation in the ER. Mechanistically, HDAC inhibitor treatment suppressed HDAC6 activity and led to increased GRP78 acetylation; acetylated GRP78 then bound to VPS34, a class III phosphoinositide-3 kinase, consequently preventing the sorting of GRP78 into multivesicular bodies (MVBs). Of note, we found that mimicking GRP78 acetylation by substituting the lysine at residue 633, one of the deacetylated sites of HDAC6, with a glutamine resulted in decreased GRP78 secretion and impaired tumour cell growth in vitro. Our study thus reveals a hitherto-unknown mechanism of GRP78 secretion and may also provide implications for the therapeutic use of HDAC inhibitors. PMID:27460191

  7. Poly(ADP-Ribosyl)ation Affects Histone Acetylation and Transcription

    PubMed Central

    Verdone, Loredana; La Fortezza, Marco; Ciccarone, Fabio; Caiafa, Paola; Zampieri, Michele; Caserta, Micaela

    2015-01-01

    Poly(ADP-ribosyl)ation (PARylation) is a posttranslational protein modification catalyzed by members of the poly(ADP-ribose) polymerase (PARP) enzyme family. PARylation regulates a wide variety of biological processes in most eukaryotic cells including energy metabolism and cell death, maintenance of genomic stability, chromatin structure and transcription. Inside the nucleus, cross-talk between PARylation and other epigenetic modifications, such as DNA and histone methylation, was already described. In the present work, using PJ34 or ABT888 to inhibit PARP activity or over-expressing poly(ADP-ribose) glycohydrolase (PARG), we show decrease of global histone H3 and H4 acetylation. This effect is accompanied by a reduction of the steady state mRNA level of p300, Pcaf, and Tnfα, but not of Dnmt1. Chromatin immunoprecipitation (ChIP) analyses, performed at the level of the Transcription Start Site (TSS) of these four genes, reveal that changes in histone acetylation are specific for each promoter. Finally, we demonstrate an increase of global deacetylase activity in nuclear extracts from cells treated with PJ34, whereas global acetyltransferase activity is not affected, suggesting a role for PARP in the inhibition of histone deacetylases. Taken together, these results show an important link between PARylation and histone acetylation regulated transcription. PMID:26636673

  8. Selective cleavage enhanced by acetylating the side chain of lysine.

    PubMed

    Fu, Leixiaomeng; Chen, Tingting; Xue, Gaiqing; Zu, Lily; Fang, Weihai

    2013-01-01

    Selective cleavage is of great interest in mass spectrometry studies as it can help sequence identification by promoting simple fragmentation pattern of peptides and proteins. In this work, the collision-induced dissociation of peptides containing internal lysine and acetylated lysine residues were studied. The experimental and computational results revealed that multiple fragmentation pathways coexisted when the lysine residue was two amino acid residues away from N-terminal of the peptide. After acetylation of the lysine side-chain, b(n)+ ions were the most abundant primary fragment products and the Lys(Ac)-Gly amide bond became the dominant cleavage site via an oxazolone pathway. Acetylating the side-chain of lysine promoted the selective cleavage of Lys-Xxx amide bond and generated much more information of the peptide backbone sequence. The results re-evaluate the selective cleavage due to the lysine basic side-chain and provide information for studying the post-translational modification of proteins and other bio-molecules containing Lys residues. PMID:23303756

  9. Chromatin decondensed by acetylation shows an elevated radiation response

    SciTech Connect

    Nackerdien, Z.; Michie, J.; Boehm, L.

    1989-02-01

    V-79 Chinese hamster lung fibroblasts exposed to 5 mM n-sodium butyrate were irradiated with 60Co gamma rays and cell survival was determined by the cell colony assay. In a separate set of experiments the acetylated chromatin obtained from these cells was irradiated and the change of molecular weight of the DNA was evaluated by alkaline sucrose density centrifugation. At a survival level of 10(-2) to 10(-4) cells exposed to butyrate were found to be 1.3-1.4 times more radiosensitive than control cells. Exposure of isolated chromatin to 100 Gy of 60Co gamma irradiation generated 0.9 +/- 0.03 single-strand breaks (ssb) per 10 Gy per 10(8) Da and 2.0 +/- 0.3 ssb/10 Gy/10(8) Da for control and acetylated chromatin, respectively. The elevated radiation sensitivity of chromatin relaxed by acetylation is in good agreement with previous results on chromatin expanded by histone H1 depletion. Packing and accessibility of DNA in chromatin appear to be major factors which influence the radiation sensitivity. The intrinsic radiation sensitivity of chromatin in various packing states is discussed in light of the variation of radiation sensitivity of whole cells in the cell cycle which incorporates repair.

  10. Carbon isotope fractionation and the acetyl-CoA pathway

    NASA Astrophysics Data System (ADS)

    Blaser, Martin; Conrad, Ralf

    2010-05-01

    Homoacetogenic bacteria can catalyze the reductive synthesis of acetate from CO2 via the acetyl-CoA pathway. Besides this unifying property homoacetogenic bacteria constitute a metabolically and phylogenetically diverse bacteriological group. Therefore their environmental role is difficult to address. It has been recognized that in methanogenic environments homoacetogenic bacteria contribute to the degradation of organic matter. The natural abundance of 13C may be used to understand the functional impact of homoacetogenic bacteria in the soil environment. To distinguish the acetyl-CoA pathway from other dominant processes, the isotopic composition of acetate and CO2 can be determined and the fractionation factors of the individual processes may be used to discriminate between the dominant pathways. To characterize the fractionation factor associated with the acetyl-CoA pathway the phylogenetic and metabolic diversity needs to be considered. Therefore the fractionation factor of substrate utilization and product formation of different homoacetogens (Acetobacterium woodii, Sporomusa ovata, Thermoanaerobacter kivui, Morella thermoautotrophica) has been studied under pure culture conditions in two defined minimal medium with H2/CO2 as sole source of carbon and energy. It became obvious that the cultivation conditions have a major impact on the obtained fractionation factors.

  11. Crystal structure of tabtoxin resistance protein complexed with acetyl coenzyme A reveals the mechanism for {beta}-lactam acetylation.

    SciTech Connect

    He, H.; Ding, Y.; Bartlam, M.; Sun, F.; Le, Y.; Qin, X.; Tang, H.; Zhang, R.; Joachimiak, A.; Liu, J.; Zhao, N.; Rao, Z.; Biosciences Division; Tsinghua Univ.; Chinese Academy of Science

    2003-01-31

    Tabtoxin resistance protein (TTR) is an enzyme that renders tabtoxin-producing pathogens, such as Pseudomonas syringae, tolerant to their own phytotoxins. Here, we report the crystal structure of TTR complexed with its natural cofactor, acetyl coenzyme A (AcCoA), to 1.55 {angstrom} resolution. The binary complex forms a characteristic 'V' shape for substrate binding and contains the four motifs conserved in the GCN5-related N-acetyltransferase (GNAT) superfamily, which also includes the histone acetyltransferases (HATs). A single-step mechanism is proposed to explain the function of three conserved residues, Glu92, Asp130 and Tyr141, in catalyzing the acetyl group transfer to its substrate. We also report that TTR possesses HAT activity and suggest an evolutionary relationship between TTR and other GNAT members.

  12. In vivo differentiation of N-acetyl aspartyl glutamate from N-acetyl aspartate at 3 Tesla.

    PubMed

    Edden, Richard A E; Pomper, Martin G; Barker, Peter B

    2007-06-01

    A method is described that allows the in vivo differentiation of N-acetyl aspartate (NAA) from N-acetyl aspartyl glutamate (NAAG) by in vivo MR spectroscopy (MRS) at 3 Tesla (3T). The method, which is based on MEGA-point-resolved spectroscopy (PRESS) editing, selectively targets the aspartyl spin system of one species while deliberately removing the other species from the spectrum. This allows quantitative measurements of NAA and NAAG without the need for fitting of unresolved peaks. White matter concentrations of NAA (6.7 +/- 0.3 mM) and NAAG (2.2 +/- 0.3 mM) were measured in 10 healthy volunteers to demonstrate the method. PMID:17534922

  13. Teen CHAT: Development and Utilization of a Web-Based Intervention to Improve Physician Communication with Adolescents About Healthy Weight

    PubMed Central

    Bravender, Terrill; Tulsky, James A.; Farrell, David; Alexander, Stewart C.; Østbye, Truls; Lyna, Pauline; Dolor, Rowena J.; Coffman, Cynthia J.; Bilheimer, Alicia; Lin, Pao-Hwa; Pollak, Kathryn I.

    2013-01-01

    Objective To describe the theoretical basis, use, and satisfaction with Teen CHAT, an online educational intervention designed to improve physician-adolescent communication about healthy weight. Methods Routine health maintenance encounters between pediatricians and family practitioners and their overweight adolescent patients were audio recorded, and content was coded to summarize adherence with motivational interviewing techniques. An online educational intervention was developed using constructs from social cognitive theory and using personalized audio recordings. Physicians were randomized to the online intervention or not, and completed post-intervention surveys. Results Forty-six physicians were recruited, and 22 physicians were randomized to view the intervention website. The educational intervention took an average of 54 minutes to complete, and most physicians thought it was useful, that they would use newly acquired skills with their patients, and would recommend it to others. Fewer physicians thought it helped them address confidentiality issues with their adolescent patients. Conclusion The Teen CHAT online intervention shows potential for enhancing physician motivational interviewing skills in an acceptable and time-efficient manner. Practice Implications If found to be effective in enhancing motivational interviewing skills and changing adolescent weight-related behaviors, wide dissemination will be feasible and indicated. PMID:24021419

  14. O-GlcNAc transferase invokes nucleotide sugar pyrophosphate participation in catalysis

    PubMed Central

    Schimpl, Marianne; Zheng, Xiaowei; Borodkin, Vladimir S.; Blair, David E.; Ferenbach, Andrew T.; Schüttelkopf, Alexander W.; Navratilova, Iva; Aristotelous, Tonia; Albarbarawi, Osama; Robinson, David A.; Macnaughtan, Megan A.; van Aalten, Daan M.F.

    2012-01-01

    Protein O-GlcNAcylation is an essential post-translational modification on hundreds of intracellular proteins in metazoa, catalyzed by O-GlcNAc transferase using unknown mechanisms of transfer and substrate recognition. Through crystallographic snapshots and mechanism-inspired chemical probes, we define how human O-GlcNAc transferase recognizes the sugar donor and acceptor peptide and employs a novel catalytic mechanism of glycosyl transfer, involving the sugar donor α-phosphate as the catalytic base, as well as an essential lysine. This mechanism appears to be a unique evolutionary solution to the spatial constraints imposed by a bulky protein acceptor substrate, and explains the unexpected specificity of a recently reported metabolic O-GlcNAc transferase inhibitor. PMID:23103942

  15. The yeast WBP1 is essential for oligosaccharyl transferase activity in vivo and in vitro.

    PubMed Central

    te Heesen, S; Janetzky, B; Lehle, L; Aebi, M

    1992-01-01

    Asparagine-linked N-glycosylation is a highly conserved and functionally important modification of proteins in eukaryotic cells. The central step in this process is a cotranslational transfer of lipid-linked core oligosaccharides to selected Asn-X-Ser/Thr-sequences of nascent polypeptide chains, catalysed by the enzyme N-oligosaccharyl transferase. In this report we show that the essential yeast protein WBP1 (te Heesen et al., 1991) is required for N-oligosaccharyl transferase in vivo and in vitro. Depletion of WBP1 correlates with a defect in transferring core oligosaccharides to carboxypeptidase Y and proteinase A in vivo. In addition, in vitro N-glycosylation of the acceptor peptide Tyr-Asn-Leu-Thr-Ser-Val using microsomal membranes from WBP1 depleted cells is reduced as compared with membranes from wild-type cells. We propose that WBP1 is an essential component of the oligosaccharyl transferase in yeast. Images PMID:1600939

  16. N-Acetyl-β-D-glucosaminidase activity in feral Carcinus maenas exposed to cadmium.

    PubMed

    Mesquita, Sofia Raquel; Ergen, Şeyda Fikirdeşici; Rodrigues, Aurélie Pinto; Oliva-Teles, M Teresa; Delerue-Matos, Cristina; Guimarães, Laura

    2015-02-01

    Cadmium is a priority hazardous substance, persistent in the aquatic environment, with the capacity to interfere with crustacean moulting. Moulting is a vital process dictating crustacean growth, reproduction and metamorphosis. However, for many organisms, moult disruption is difficult to evaluate in the short term, what limits its inclusion in monitoring programmes. N-acetyl-β-D-glucosaminidase (NAGase) is an enzyme acting in the final steps of the endocrine-regulated moulting cascade, allowing for the cast off of the old exoskeleton, with potential interest as a biomarker of moult disruption. This study investigated responses to waterborne cadmium of NAGase activity of Carcinus maenas originating from estuaries with different histories of anthropogenic contamination: a low impacted and a moderately polluted one. Crabs from both sites were individually exposed for seven days to cadmium concentrations ranging from 1.3 to 2000 μg/L. At the end of the assays, NAGase activity was assessed in the epidermis and digestive gland. Detoxification, antioxidant, energy production, and oxidative stress biomarkers implicated in cadmium metabolism and tolerance were also assessed to better understand differential NAGase responses: activity of glutathione S-transferases (GST), glutathione peroxidase (GPx) glutathione reductase (GR), levels of total glutathiones (TG), lipid peroxidation (LPO), lactate dehydrogenase (LDH), and NADP(+)-dependent isocitrate dehydrogenase (IDH). Animals from the moderately polluted estuary had lower NAGase activity both in the epidermis and digestive gland than in the low impacted site. NAGase activity in the epidermis and digestive gland of C. maenas from both estuaries was sensitive to cadmium exposure suggesting its usefulness for inclusion in monitoring programmes. However, in the digestive gland NAGase inhibition was found in crabs from the less impacted site but not in those from the moderately contaminated one. Altered glutathione levels were

  17. Acetylation of Werner syndrome protein (WRN): relationships with DNA damage, DNA replication and DNA metabolic activities

    PubMed Central

    Lozada, Enerlyn; Yi, Jingjie; Luo, Jianyuan; Orren, David K.

    2014-01-01

    Loss of WRN function causes Werner Syndrome, characterized by increased genomic instability, elevated cancer susceptibility and premature aging. Although WRN is subject to acetylation, phosphorylation and sumoylation, the impact of these modifications on WRN’s DNA metabolic function remains unclear. Here, we examined in further depth the relationship between WRN acetylation and its role in DNA metabolism, particularly in response to induced DNA damage. Our results demonstrate that endogenous WRN is acetylated somewhat under unperturbed conditions. However, levels of acetylated WRN significantly increase after treatment with certain DNA damaging agents or the replication inhibitor hydroxyurea. Use of DNA repair-deficient cells or repair pathway inhibitors further increase levels of acetylated WRN, indicating that induced DNA lesions and their persistence are at least partly responsible for increased acetylation. Notably, acetylation of WRN correlates with inhibition of DNA synthesis, suggesting that replication blockage might underlie this effect. Moreover, WRN acetylation modulates its affinity for and activity on certain DNA structures, in a manner that may enhance its relative specificity for physiological substrates. Our results also show that acetylation and deacetylation of endogenous WRN is a dynamic process, with sirtuins and other histone deacetylases contributing to WRN deacetylation. These findings advance our understanding of the dynamics of WRN acetylation under unperturbed conditions and following DNA damage induction, linking this modification not only to DNA damage persistence but also potentially to replication stalling caused by specific DNA lesions. Our results are consistent with proposed metabolic roles for WRN and genomic instability phenotypes associated with WRN deficiency. PMID:24965941

  18. Acetylation mimic of lysine 280 exacerbates human Tau neurotoxicity in vivo

    PubMed Central

    Gorsky, Marianna Karina; Burnouf, Sylvie; Dols, Jacqueline; Mandelkow, Eckhard; Partridge, Linda

    2016-01-01

    Dysfunction and accumulation of the microtubule-associated human Tau (hTau) protein into intraneuronal aggregates is observed in many neurodegenerative disorders including Alzheimer’s disease (AD). Reversible lysine acetylation has recently emerged as a post-translational modification that may play an important role in the modulation of hTau pathology. Acetylated hTau species have been observed within hTau aggregates in human AD brains and multi-acetylation of hTau in vitro regulates its propensity to aggregate. However, whether lysine acetylation at position 280 (K280) modulates hTau-induced toxicity in vivo is unknown. We generated new Drosophila transgenic models of hTau pathology to evaluate the contribution of K280 acetylation to hTau toxicity, by analysing the respective toxicity of pseudo-acetylated (K280Q) and pseudo-de-acetylated (K280R) mutant forms of hTau. We observed that mis-expression of pseudo-acetylated K280Q-hTau in the adult fly nervous system potently exacerbated fly locomotion defects and photoreceptor neurodegeneration. In addition, modulation of K280 influenced total hTau levels and phosphorylation without changing hTau solubility. Altogether, our results indicate that pseudo-acetylation of the single K280 residue is sufficient to exacerbate hTau neurotoxicity in vivo, suggesting that acetylated K280-hTau species contribute to the pathological events leading to neurodegeneration in AD. PMID:26940749

  19. Proteome-wide analysis reveals widespread lysine acetylation of major protein complexes in the malaria parasite

    PubMed Central

    Cobbold, Simon A.; Santos, Joana M.; Ochoa, Alejandro; Perlman, David H.; Llinás, Manuel

    2016-01-01

    Lysine acetylation is a ubiquitous post-translational modification in many organisms including the malaria parasite Plasmodium falciparum, yet the full extent of acetylation across the parasite proteome remains unresolved. Moreover, the functional significance of acetylation or how specific acetyl-lysine sites are regulated is largely unknown. Here we report a seven-fold expansion of the known parasite ‘acetylome’, characterizing 2,876 acetylation sites on 1,146 proteins. We observe that lysine acetylation targets a diverse range of protein complexes and is particularly enriched within the Apicomplexan AP2 (ApiAP2) DNA-binding protein family. Using quantitative proteomics we determined that artificial perturbation of the acetate/acetyl-CoA balance alters the acetyl-lysine occupancy of several ApiAP2 DNA-binding proteins and related transcriptional proteins. This metabolic signaling could mediate significant downstream transcriptional responses, as we show that acetylation of an ApiAP2 DNA-binding domain ablates its DNA-binding propensity. Lastly, we investigated the acetyl-lysine targets of each class of lysine deacetylase in order to begin to explore how each class of enzyme contributes to regulating the P. falciparum acetylome. PMID:26813983

  20. MeIQx-induced DNA adduct formation and mutagenesis in DNA repair deficient CHO cells expressing human CYP1A1 and rapid or slow acetylator NAT2

    PubMed Central

    Bendaly, Jean; Zhao, Shuang; Neale, Jason R.; Metry, Kristin J.; Doll, Mark A.; States, J. Christopher; Pierce, William M.; Hein, David W.

    2007-01-01

    2-Amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx) is one of the most potent and abundant mutagens in the western diet. Bioactivation includes N-hydroxylation catalyzed by cytochrome P450s followed by O-acetylation catalyzed by N-acetyltransferase 2 (NAT2). Nucleotide excision repair-deficient chinese hamster ovary (CHO) cells were constructed by stable transfection of human cytochrome P4501A1 (CYP1A1) and a single copy of either NAT2*4 (rapid acetylator) or NAT2*5B (slow acetylator) alleles. CYP1A1 and NAT2 catalytic activities were undetectable in untransfected CHO cell lines. CYP1A1 activity did not differ significantly (p > 0.05) among the CYP1A1-transfected cell lines. Cells transfected with NAT2*4 had significantly higher levels of sulfamethazine N-acetyltransferase (p = 0.0001) and N-hydroxy-MeIQx O-acetyltransferase (p = 0.0093) catalytic activity than cells transfected with NAT2*5B. Only cells transfected with both CYP1A1 and NAT2*4 showed concentration-dependent cytotoxicity and hypoxanthine phosphoribosyl transferase (hprt) mutagenesis following MeIQx treatment. dG-C8-MeIQx was the primary DNA adduct formed and levels were dose-dependent in each cell line and in the order: untransfected < transfected with CYP1A1 < transfected with CYP1A1 & NAT2*5B < transfected with CYP1A1 & NAT2*4. MeIQx DNA adduct levels were significantly higher (p < 0.001) in CYP1A1/NAT2*4 than CYP1A1/NAT2*5B cells at all concentrations of MeIQx tested. MeIQx-induced DNA adduct levels correlated very highly (r2 = 0.88) with MeIQx-induced mutants. These results strongly support extrahepatic activation of MeIQx by CYP1A1 and a robust effect of human NAT2 genetic polymorphism on MeIQx –induced DNA adducts and mutagenesis. The results provide laboratory-based support for epidemiological studies reporting higher frequency of heterocyclic amine-related cancers in rapid NAT2 acetylators. PMID:17627018

  1. Terminal Deoxynucleotidyl Transferase in a Case of Childhood Acute Lymphoblastic Leukemia

    PubMed Central

    McCaffrey, Ronald; Smoler, Donna F.; Baltimore, David

    1973-01-01

    Cells from a patient with childhood acute lymphoblastic leukemia contain an apparent DNA polymerase activity that was not found in any other cells except thymus cells. The enzyme has the properties of terminal transferase, an enzyme known to be found in thymocytes. The cells also contain the three major DNA polymerases found in growing cells. The results suggest that these tumor cells arose from a block in the differentiation of thymocytes. Terminal transferase may be a marker for the origin of leukemic cells. PMID:4346893

  2. Type II Hydride Transferases from Different Microorganisms Yield Nitrite and Diarylamines from Polynitroaromatic Compounds▿ †

    PubMed Central

    van Dillewijn, Pieter; Wittich, Rolf-Michael; Caballero, Antonio; Ramos, Juan-Luis

    2008-01-01

    Homogenous preparations of XenB of Pseudomonas putida, pentaerythritol tetranitrate reductase of Enterobacter cloacae, and N-ethylmaleimide reductase of Escherichia coli, all type II hydride transferases of the Old Yellow Enzyme family of flavoproteins, are shown to reduce the polynitroaromatic compound 2,4,6-trinitrotoluene (TNT). The reduction of this compound yields hydroxylaminodinitrotoluenes and Meisenheimer dihydride complexes, which, upon condensation, yield stoichiometric amounts of nitrite and diarylamines, implying that type II hydride transferases are responsible for TNT denitration, a process with important environmental implications for TNT remediation. PMID:18791007

  3. Lysine deacetylase inhibition attenuates hypertension and is accompanied by acetylation of mineralocorticoid receptor instead of histone acetylation in spontaneously hypertensive rats.

    PubMed

    Seok, Young Mi; Lee, Hae Ahm; Park, Kwon Moo; Hwangbo, Mi-Hyang; Kim, In Kyeom

    2016-07-01

    Inhibition of lysine deacetylase (KDAC) attenuated development of hypertension in spontaneously hypertensive rats (SHRs). We hypothesized that KDAC inhibition attenuates hypertension and is accompanied by acetylation of mineralocorticoid receptors (MR) instead of histone acetylation in SHRs. Valproate (VPA, 0.71 % wt/vol), an inhibitor of class I KDACs, was administered in drinking water to 7-week-old SHRs and Wistar Kyoto rats for 11 weeks. MR acetylation was determined by immunoprecipitation with anti-MR antibody followed by western blot with anti-acetyl-lysine antibody. Expression levels of acetylated histone H3, KDACs, MR target genes, or MR corepressors in the kidney cortex were measured by using western blot analysis or real-time PCR. Recruitment of MR and RNA polymerase II (Pol II) and histone modifications on promoters of target genes were analyzed by performing a chromatin immunoprecipitation (ChIP) assay. Treatment of SHR with VPA increased MR acetylation without affecting MR expression, which attenuated development of hypertension in SHR VPA decreased expression of KDAC class I but globally increased acetylated histone H3. Although VPA treatment increased histone 3 acetylation (H3Ac) and trimethylation of the fourth lysine (H3K4me3) in the promoter regions of MR target genes, it decreased the expression of target genes as well as recruitment of MR and Pol II. These results suggest that KDAC inhibition attenuates the development of hypertension in SHRs and is accompanied by acetylation of MR that is independent of histone acetylation. PMID:27106211

  4. Acetylator genotype-dependent formation of 2-aminofluorene-hemoglobin adducts in rapid and slow acetylator Syrian hamsters congenic at the NAT2 locus.

    PubMed

    Feng, Y; Rustan, T D; Ferguson, R J; Doll, M A; Hein, D W

    1994-01-01

    Arylamine-hemoglobin adducts are a valuable dosimeter for assessing arylamine exposures and carcinogenic risk. The effects of age, sex, time-course, dose, and acetylator genotype on levels of 2-aminofluorene-hemoglobin adducts were investigated in homozygous rapid (Bio. 82.73/H-Patr) and slow (Bio. 82.73/H-Pats) acetylator hamsters congenic at the polymorphic (NAT2) acetylator locus. Following administration of a single ip dose of [3H]2-aminofluorene, peak 2-aminofluorene-hemoglobin adduct levels were achieved at 12-18 hr and retained a plateau up to 72 hr postinjection in both rapid and slow acetylator congenic hamsters. 2-Aminofluorene-hemoglobin adduct levels did not differ significantly between young (5-6 weeks) and old (32-49 weeks) hamsters or between male and female hamsters within either acetylator genotype. 2-Aminofluorene-hemoglobin adduct levels increased in a dose-dependent manner (r = 0.95, p = 0.0001) and were consistently higher in slow versus rapid acetylator congenic hamsters in studies of both time-course and dose-effect. The magnitude of the acetylator genotype-dependent difference was a function of dose; 2-aminofluorene-hemoglobin adduct levels were 1.5-fold higher in slow acetylator congenic hamsters following a 60 mg/kg 2-aminofluorene dose (p = 0.0013) but 2-fold higher following a 100 mg/kg 2-aminofluorene dose (p < 0.0001). These results show a specific and significant role for NAT2 acetylator genotype in formation of arylamine-hemoglobin adducts, which may reflect the relationship between acetylator genotype and the incidence of different cancers from arylamine exposures. PMID:8291051

  5. New short and general synthesis of three key Maillard flavour compounds: 2-Acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine.

    PubMed

    Deblander, Jurgen; Van Aeken, Sam; Adams, An; De Kimpe, Norbert; Abbaspour Tehrani, Kourosch

    2015-02-01

    A new general synthetic route towards three key Maillard flavour compounds, namely 2-acetyl-1-pyrroline, 6-acetyl-1,2,3,4-tetrahydropyridine and 5-acetyl-2,3-dihydro-4H-1,4-thiazine, was developed. The key step in the process is the methylenation reaction of azaheterocyclic carboxylic esters by means of dimethyltitanocene, giving rise to intermediate vinyl ethers which can be considered as excellent and stable precursors for the title compounds, as a simple acidic treatment of these precursors suffices to release the characteristic Maillard flavours. PMID:25172717

  6. Linguistic Affordances of Korean-English Tandem Learning: A Case Study of Korean-English On-Line Chat Pair Interaction

    ERIC Educational Resources Information Center

    Cheon, Heesok

    2012-01-01

    In an attempt to explore an environment for language learning that tandem learning via real-time chat affords to foreign language learners and how language learners respond to those affordances, this study examined learner interaction in online Korean-English Tandem Learning with focus on how tandem learners engaged in peer assistance and how they…

  7. Less Words, More Action: Using On-the-Fly Videos and Screenshots in Your Library's IM/Chat and Email Reference Transactions

    ERIC Educational Resources Information Center

    Sekyere, Kwabena

    2010-01-01

    Email and chat/IM reference services have become a convenient and easily accessible option for the online community and libraries, particularly with increasing amounts of library resources now available electronically. This article gives an overview of Jing, which can be used to produce videos and screenshots on-the-fly, and demonstrates how to…

  8. The Influence of Group Formation on Learner Participation, Language Complexity, and Corrective Behaviour in Synchronous Written Chat as Part of Academic German Studies

    ERIC Educational Resources Information Center

    Fredriksson, Christine

    2015-01-01

    Synchronous written chat and instant messaging are tools which have been used and explored in online language learning settings for at least two decades. Research literature has shown that such tools give second language (L2) learners opportunities for language learning, e.g. , the interaction in real time with peers and native speakers, the…

  9. Purification and Biochemical Characterization of Glutathione S-Transferase from Down Syndrome and Normal Children Erythrocytes: A Comparative Study

    ERIC Educational Resources Information Center

    Hamed, Ragaa R.; Maharem, Tahany M.; Abdel-Meguid, Nagwa; Sabry, Gilane M.; Abdalla, Abdel-Monem; Guneidy, Rasha A.

    2011-01-01

    Down syndrome (DS) is the phenotypic manifestation of trisomy 21. Our study was concerned with the characterization and purification of glutathione S-transferase enzyme (GST) from normal and Down syndrome (DS) erythrocytes to illustrate the difference in the role of this enzyme in the cell. Glutathione S-transferase and glutathione (GSH) was…

  10. O-acetylated oligosaccharides from pectins of potato tuber cell walls.

    PubMed Central

    Ishii, T

    1997-01-01

    Acetylated trigalacturonides and rhamnogalacturonan I (RG-I)-derived oligosaccharides were isolated from a Driselase digest of potato tuber cell walls by ion-exchange and size-exclusion chromatography. The oligosaccharides were structurally characterized by fast atom bombardment-mass spectroscopy, nuclear magnetic resonance spectroscopy, and glycosyl-linkage composition analysis. One trigalacturonide contained a single acetyl group at O-3 of the reducing galacturonic acid residue. A second trigalacturonide contained two acetyl substituents, which were located on O-3 or O-4 of the nonreducing galacturonic acid residue and O-3 of the reducing galacturonic acid residue. RG-I backbone-derived oligomers had acetyl groups at O-2 of the galacturonic acid residues. Some of these galacturonic acid residues were O-acetylated at both O-2 and O-3 positions. Rhamnosyl residues of RG-I oligomers were not acetylated. PMID:9112775

  11. Acetylated starch nanocrystals: Preparation and antitumor drug delivery study.

    PubMed

    Xiao, Huaxi; Yang, Tao; Lin, Qinlu; Liu, Gao-Qiang; Zhang, Lin; Yu, Fengxiang; Chen, Yuejiao

    2016-08-01

    In this study, we developed a new nanoparticulate system for acetylated starch nanocrystals (ASN) using broken rice. ASN with different degrees of substitution (DS) of 0.04, 0.08 and 0.14 were prepared using acetic anhydride as acetylating agent through reaction with starch nanocrystals (SN). The resulting ASN were investigated for the capability to load and release doxorubicin hydrochloride (DOX), and the antitumor activities of DOX-loaded SN and DOX-loaded ASN were evaluated as potential drug delivery systems for cancer therapy. Cellular uptake and cytotoxicity of nanocrystals and the DOX-loaded nanocrystals were investigated using fluorescence microscopy and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. Compared with acetylated starches (AS) and native starches (NS), ASN with DS 0.14 loaded up to 6.07% of DOX with a higher loading efficiency of 91.1% and had steadier drug-release rates. Toxicity analysis using the rat hepatocytes model suggested that ASN was biocompatible and could be used for drug delivery. Furthermore, ASN were taken up by cancer cells in vitro and significantly enhanced the cytotoxicity of DOX against HeLa human cervical carcinoma cells. The IC50 value of DOX-loaded ASN-DS 0.14 was 3.8μg/mL for 24h of treatment, which was significantly lower than that of free DOX (21μg/mL). These results indicate that the prepared ASN using broken rice is a promising vehicle for the controlled delivery of DOX for cancer therapy. PMID:27156696

  12. Autoimmune regulator is acetylated by transcription coactivator CBP/p300

    SciTech Connect

    Saare, Mario; Rebane, Ana; Rajashekar, Balaji; Vilo, Jaak; Peterson, Paert

    2012-08-15

    The Autoimmune Regulator (AIRE) is a regulator of transcription in the thymic medulla, where it controls the expression of a large set of peripheral-tissue specific genes. AIRE interacts with the transcriptional coactivator and acetyltransferase CBP and synergistically cooperates with it in transcriptional activation. Here, we aimed to study a possible role of AIRE acetylation in the modulation of its activity. We found that AIRE is acetylated in tissue culture cells and this acetylation is enhanced by overexpression of CBP and the CBP paralog p300. The acetylated lysines were located within nuclear localization signal and SAND domain. AIRE with mutations that mimicked acetylated K243 and K253 in the SAND domain had reduced transactivation activity and accumulated into fewer and larger nuclear bodies, whereas mutations that mimicked the unacetylated lysines were functionally similar to wild-type AIRE. Analogously to CBP, p300 localized to AIRE-containing nuclear bodies, however, the overexpression of p300 did not enhance the transcriptional activation of AIRE-regulated genes. Further studies showed that overexpression of p300 stabilized the AIRE protein. Interestingly, gene expression profiling revealed that AIRE, with mutations mimicking K243/K253 acetylation in SAND, was able to activate gene expression, although the affected genes were different and the activation level was lower from those regulated by wild-type AIRE. Our results suggest that the AIRE acetylation can influence the selection of AIRE activated genes. -- Highlights: Black-Right-Pointing-Pointer AIRE is acetylated by the acetyltransferases p300 and CBP. Black-Right-Pointing-Pointer Acetylation occurs between CARD and SAND domains and within the SAND domain. Black-Right-Pointing-Pointer Acetylation increases the size of AIRE nuclear dots. Black-Right-Pointing-Pointer Acetylation increases AIRE protein stability. Black-Right-Pointing-Pointer AIRE acetylation mimic regulates a different set of AIRE

  13. Tubulin Acetylation Alone Does Not Affect Kinesin-1 Velocity and Run Length In Vitro

    PubMed Central

    Walter, Wilhelm J.; Beránek, Václav; Fischermeier, Elisabeth; Diez, Stefan

    2012-01-01

    Kinesin-1 plays a major role in anterograde transport of intracellular cargo along microtubules. Currently, there is an ongoing debate of whether α-tubulin K40 acetylation directly enhances the velocity of kinesin-1 and its affinity to the microtubule track. We compared motor motility on microtubules reconstituted from acetylated and deacetylated tubulin. For both, single- and multi-motor in vitro motility assays, we demonstrate that tubulin acetylation alone does not affect kinesin-1 velocity and run length. PMID:22870307

  14. Therapeutics Targeting Protein Acetylation Perturb Latency of Human Viruses.

    PubMed

    Conrad, Ryan J; Ott, Melanie

    2016-03-18

    Persistent viral infections are widespread and represent significant public health burdens. Some viruses endure in a latent state by co-opting the host epigenetic machinery to manipulate viral gene expression. Small molecules targeting epigenetic pathways are now in the clinic for certain cancers and are considered as potential treatment strategies to reverse latency in HIV-infected individuals. In this review, we discuss how drugs interfering with one epigenetic pathway, protein acetylation, perturb latency of three families of pathogenic human viruses-retroviruses, herpesviruses, and papillomaviruses. PMID:26845514

  15. Sulfation of deoxynivalenol, its acetylated derivatives, and T2-toxin☆

    PubMed Central

    Fruhmann, Philipp; Skrinjar, Philipp; Weber, Julia; Mikula, Hannes; Warth, Benedikt; Sulyok, Michael; Krska, Rudolf; Adam, Gerhard; Rosenberg, Erwin; Hametner, Christian; Fröhlich, Johannes

    2014-01-01

    The synthesis of several sulfates of trichothecene mycotoxins is presented. Deoxynivalenol (DON) and its acetylated derivatives were synthesized from 3-acetyldeoxynivalenol (3ADON) and used as substrate for sulfation in order to reach a series of five different DON-based sulfates as well as T2-toxin-3-sulfate. These substances are suspected to be formed during phase-II metabolism in plants and humans. The sulfation was performed using a sulfuryl imidazolium salt, which was synthesized prior to use. All protected intermediates and final products were characterized via NMR and will serve as reference materials for further investigations in the fields of toxicology and bioanalytics of mycotoxins. PMID:25170180

  16. Epigenetic Readers of Lysine Acetylation Regulate Cocaine-Induced Plasticity

    PubMed Central

    Sartor, Gregory C.; Powell, Samuel K.; Brothers, Shaun P.

    2015-01-01

    Epigenetic processes that regulate histone acetylation play an essential role in behavioral and molecular responses to cocaine. To date, however, only a small fraction of the mechanisms involved in the addiction-associated acetylome have been investigated. Members of the bromodomain and extraterminal (BET) family of epigenetic “reader” proteins (BRD2, BRD3, BRD4, and BRDT) bind acetylated histones and serve as a scaffold for the recruitment of macromolecular complexes to modify chromatin accessibility and transcriptional activity. The role of BET proteins in cocaine-induced plasticity, however, remains elusive. Here, we used behavioral, pharmacological, and molecular techniques to examine the involvement of BET bromodomains in cocaine reward. Of the BET proteins, BRD4, but not BRD2 or BRD3, was significantly elevated in the nucleus accumbens (NAc) of mice and rats following repeated cocaine injections and self-administration. Systemic and intra-accumbal inhibition of BRD4 with the BET inhibitor, JQ1, attenuated the rewarding effects of cocaine in a conditioned place preference procedure but did not affect conditioned place aversion, nor did JQ1 alone induce conditioned aversion or preference. Investigating the underlying mechanisms, we found that repeated cocaine injections enhanced the binding of BRD4, but not BRD3, to the promoter region of Bdnf in the NAc, whereas systemic injection of JQ1 attenuated cocaine-induced expression of Bdnf in the NAc. JQ1 and siRNA-mediated knockdown of BRD4 in vitro also reduced expression of Bdnf. These findings indicate that disrupting the interaction between BET proteins and their acetylated lysine substrates may provide a new therapeutic avenue for the treatment of drug addiction. SIGNIFICANCE STATEMENT Proteins involved in the “readout” of lysine acetylation marks, referred to as BET bromodomain proteins (including BRD2, BRD3, BRD4, and BRDT), have been shown to be key regulators of chromatin dynamics and disease, and

  17. Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis1[C][W][OPEN

    PubMed Central

    Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha; Harholt, Jesper; Chong, Sun-Li; Pawar, Prashant Mohan-Anupama; Mellerowicz, Ewa J.; Tenkanen, Maija; Cheng, Kun; Pauly, Markus; Scheller, Henrik Vibe

    2013-01-01

    The Reduced Wall Acetylation (RWA) proteins are involved in cell wall acetylation in plants. Previously, we described a single mutant, rwa2, which has about 20% lower level of O-acetylation in leaf cell walls and no obvious growth or developmental phenotype. In this study, we generated double, triple, and quadruple loss-of-function mutants of all four members of the RWA family in Arabidopsis (Arabidopsis thaliana). In contrast to rwa2, the triple and quadruple rwa mutants display severe growth phenotypes revealing the importance of wall acetylation for plant growth and development. The quadruple rwa mutant can be completely complemented with the RWA2 protein expressed under 35S promoter, indicating the functional redundancy of the RWA proteins. Nevertheless, the degree of acetylation of xylan, (gluco)mannan, and xyloglucan as well as overall cell wall acetylation is affected differently in different combinations of triple mutants, suggesting their diversity in substrate preference. The overall degree of wall acetylation in the rwa quadruple mutant was reduced by 63% compared with the wild type, and histochemical analysis of the rwa quadruple mutant stem indicates defects in cell differentiation of cell types with secondary cell walls. PMID:24019426

  18. Aspirin acetylates wild type and mutant p53 in colon cancer cells: identification of aspirin acetylated sites on recombinant p53.

    PubMed

    Ai, Guoqiang; Dachineni, Rakesh; Kumar, D Ramesh; Marimuthu, Srinivasan; Alfonso, Lloyd F; Bhat, G Jayarama

    2016-05-01

    Aspirin's ability to inhibit cell proliferation and induce apoptosis in cancer cell lines is considered to be an important mechanism for its anti-cancer effects. We previously demonstrated that aspirin acetylated the tumor suppressor protein p53 at lysine 382 in MDA-MB-231 human breast cancer cells. Here, we extended these observations to human colon cancer cells, HCT 116 harboring wild type p53, and HT-29 containing mutant p53. We demonstrate that aspirin induced acetylation of p53 in both cell lines in a concentration-dependent manner. Aspirin-acetylated p53 was localized to the nucleus. In both cell lines, aspirin induced p21(CIP1). Aspirin also acetylated recombinant p53 (rp53) in vitro suggesting that it occurs through a non-enzymatic chemical reaction. Mass spectrometry analysis and immunoblotting identified 10 acetylated lysines on rp53, and molecular modeling showed that all lysines targeted by aspirin are surface exposed. Five of these lysines are localized to the DNA-binding domain, four to the nuclear localization signal domain, and one to the C-terminal regulatory domain. Our results suggest that aspirin's anti-cancer effect may involve acetylation and activation of wild type and mutant p53 and induction of target gene expression. This is the first report attempting to characterize p53 acetylation sites targeted by aspirin. PMID:26596838

  19. [(1)H] magnetic resonance spectroscopy of urine: diagnosis of a guanidinoacetate methyl transferase deficiency case.

    PubMed

    Tassini, Maria; Zannolli, Raffaella; Buoni, Sabrina; Engelke, Udo; Vivi, Antonio; Valensin, Gianni; Salomons, Gajja S; De Nicola, Anna; Strambi, Mirella; Monti, Lucia; Morava, Eva; Wevers, Ron A; Hayek, Joseph

    2010-01-01

    For the first time, the use of urine [(1)H] magnetic resonance spectroscopy has allowed the detection of 1 case of guanidinoacetate methyl transferase in a database sample of 1500 pediatric patients with a diagnosis of central nervous system impairment of unknown origin. The urine [(1)H] magnetic resonance spectroscopy of a 9-year-old child, having severe epilepsy and nonprogressive mental and motor retardation with no apparent cause, revealed a possible guanidinoacetic acid increase. The definitive assignment of guanidinoacetic acid was checked by addition of pure substance to the urine sample and by measuring [(1)H]-[(1)H] correlation spectroscopy. Diagnosis of guanidinoacetate methyl transferase deficiency was further confirmed by liquid chromatography-mass spectrometry, brain [(1)H] magnetic resonance spectroscopy, and mutational analysis of the guanidinoacetate methyl transferase gene. The replacement therapy was promptly started and, after 1 year, the child was seizure free. We conclude that for this case, urine [(1)H] magnetic resonance spectroscopy screening was able to diagnose guanidinoacetate methyl transferase deficiency. PMID:19461121

  20. Maize white seedling 3 results from disruption of homogentisate solanesyl transferase

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Maize white seedling 3 (w3) has served as a model albino-seedling mutant since its discovery in 1923. We show here that the w3 phenotype is caused by disruptions in homogentisate solanesyl transferase (HST), an enzyme that catalyzes the committed step in plastoquinone-9 (PQ9) biosynthesis. This re...

  1. Effect of salicylates on histamine and L-histidine metabolism. Inhibition of imidazoleacetate phosphoribosyl transferase.

    PubMed Central

    Moss, J; De Mello, M C; Vaughan, M; Beaven, M A

    1976-01-01

    In man and other animals, urinary excretion of the histidine and histamine metabolite, imidazoleacetate, is increased and that of its conjugated metabolite, ribosylimidazoleacetate, decreased by salicylates. Imidazoleacetate has been reported to produce analgesia and narcosis. Its accumulation as a result of transferase inhibition could play a part in the therapeutic effects of salicylates. To determine the locus of salicylate action, we have investigated the effect of anti-inflammatory drugs on imidazoleacetate phosphoribosyl transferase, the enzyme that catalyzes the ATP-dependent conjugation of imidazoleacetate with phosphoribosylpyrophosphate. As little as 0.2 mM aspirin produced 50% inhibition of the rat liver transferase. In vivo, a 30% decrease in the urinary excretion of ribosylimidazoleacetate has been observed with plasma salicylate concentrations of 0.4 mM. The enzyme was also inhibited by sodium salicylate but not by salicylamide, sodium gentisate, aminopyrine, phenacetin, phenylbutazone, or indomethacin. The last four drugs have been shown previously not to alter the excretion of ribosylimidazoleacetate when administered in vivo. Since both the drug specificity and inhibitory concentrations are similar in vivo and in vitro, it seems probable that the effect of salicylates on imidazoleacetate conjugation results from inhibition of imidazoleacetate phosphoribosyl transferase. PMID:180057

  2. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  3. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  4. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  5. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  6. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  7. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  8. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  9. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  10. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  11. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  12. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  13. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  14. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  15. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  16. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  17. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...

  18. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... hereditary disease galactosemia (disorder of galactose metabolism) in infants. (b) Classification. Class II....

  19. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... hereditary disease galactosemia (disorder of galactose metabolism) in infants. (b) Classification. Class II....

  20. Preliminary X-ray crystallographic analysis of glutathione transferase zeta 1 (GSTZ1a-1a)

    SciTech Connect

    Boone, Christopher D.; Zhong, Guo; Smeltz, Marci; James, Margaret O. McKenna, Robert

    2014-01-21

    Crystals of glutathione transferase zeta 1 were grown and shown to diffract X-rays to 3.1 Å resolution. They belonged to space group P1, with unit-cell parameters a = 42.0, b = 49.6, c = 54.6 Å, α = 82.9, β = 69.9, γ = 73.4°.

  1. DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1

    EPA Science Inventory


    DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1. R A Pegram1 and M K Ross2. 2Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC; 1Pharmacokinetics Branch, NHEERL, ORD, United States Environmental Protection Ag...

  2. GLUTATHIONE S-TRANSFERASE THETA 1-1-DEPENDENT METABOLISM OF THE DISINFECTION BYPRODUCT BROMODICHLOROMETHANE

    EPA Science Inventory

    ABSTRACT
    Bromodichloromethane (BDCM), a prevalent drinking water disinfection by-product, was previously shown to be mutagenic in Salmonella expressing glutathione S-transferase (GST) theta 1-1 (GST T1-1). In the present study, in vitro experiments were performed to study the...

  3. A tyrosine-reactive irreversible inhibitor for glutathione S-transferase Pi (GSTP1).

    PubMed

    Crawford, L A; Weerapana, E

    2016-05-24

    Glutathione S-transferase Pi (GSTP1) mediates cellular defense against reactive electrophiles. Here, we report LAS17, a dichlorotriazine-containing compound that irreversibly inhibits GSTP1 and is selective for GSTP1 within cellular proteomes. Mass spectrometry and mutational studies identified Y108 as the site of modification, providing a unique mode of GSTP1 inhibition. PMID:27113843

  4. p53 targets simian virus 40 large T antigen for acetylation by CBP.

    PubMed

    Poulin, Danielle L; Kung, Andrew L; DeCaprio, James A

    2004-08-01

    Simian virus 40 (SV40) large T antigen (T Ag) interacts with the tumor suppressor p53 and the transcriptional coactivators CBP and p300. Binding of these cellular proteins in a ternary complex has been implicated in T Ag-mediated transformation. It has been suggested that the ability of CBP/p300 to modulate p53 function underlies p53's regulation of cell proliferation and tumorigenesis. In this study, we provide further evidence that CBP activity may be mediated through its synergistic action with p53. We demonstrate that SV40 T Ag is acetylated in vivo in a p53-dependent manner and T Ag acetylation is largely mediated by CBP. The acetylation of T Ag is dependent on its interaction with p53 and on p53's interaction with CBP. We have mapped the site of acetylation on T Ag to the C-terminal lysine residue 697. This acetylation site is conserved between the T antigens of the human polyomaviruses JC and BK, which are also known to interact with p53. We show that both JC and BK T antigens are also acetylated at corresponding sites in vivo. While other proteins are known to be acetylated by CBP/p300, none are known to depend on p53 for acetylation. T Ag acetylation may provide a regulatory mechanism for T Ag binding to a cellular factor or play a role in another aspect of T Ag function. PMID:15254196

  5. First Comprehensive Proteome Analyses of Lysine Acetylation and Succinylation in Seedling Leaves of Brachypodium distachyon L.

    PubMed Central

    Zhen, Shoumin; Deng, Xiong; Wang, Jian; Zhu, Gengrui; Cao, Hui; Yuan, Linlin; Yan, Yueming

    2016-01-01

    Protein acetylation and succinylation are the most crucial protein post-translational modifications (PTMs) involved in the regulation of plant growth and development. In this study, we present the first lysine-acetylation and lysine-succinylation proteome analysis of seedling leaves in Brachypodium distachyon L (Bd). Using high accuracy nano LC-MS/MS combined with affinity purification, we identified a total of 636 lysine-acetylated sites in 353 proteins and 605 lysine-succinylated sites in 262 proteins. These proteins participated in many biology processes, with various molecular functions. In particular, 119 proteins and 115 sites were found to be both acetylated and succinylated, simultaneously. Among the 353 acetylated proteins, 148 had acetylation orthologs in Oryza sativa L., Arabidopsis thaliana, Synechocystis sp. PCC 6803, and Glycine max L. Among the 262 succinylated proteins, 170 of them were found to have homologous proteins in Oryza sativa L., Escherichia coli, Sacchayromyces cerevisiae, or Homo sapiens. Motif-X analysis of the acetylated and succinylated sites identified two new acetylated motifs (K---K and K-I-K) and twelve significantly enriched succinylated motifs for the first time, which could serve as possible binding loci for future studies in plants. Our comprehensive dataset provides a promising starting point for further functional analysis of acetylation and succinylation in Bd and other plant species. PMID:27515067

  6. Sirtuin-dependent reversible lysine acetylation of glutamine synthetases reveals an autofeedback loop in nitrogen metabolism.

    PubMed

    You, Di; Yin, Bin-Cheng; Li, Zhi-Hai; Zhou, Ying; Yu, Wen-Bang; Zuo, Peng; Ye, Bang-Ce

    2016-06-14

    In cells of all domains of life, reversible lysine acetylation modulates the function of proteins involved in central cellular processes such as metabolism. In this study, we demonstrate that the nitrogen regulator GlnR of the actinomycete Saccharopolyspora erythraea directly regulates transcription of the acuA gene (SACE_5148), which encodes a Gcn5-type lysine acetyltransferase. We found that AcuA acetylates two glutamine synthetases (GlnA1 and GlnA4) and that this lysine acetylation inactivated GlnA4 (GSII) but had no significant effect on GlnA1 (GSI-β) activity under the conditions tested. Instead, acetylation of GlnA1 led to a gain-of-function that modulated its interaction with the GlnR regulator and enhanced GlnR-DNA binding. It was observed that this regulatory function of acetylated GSI-β enzymes is highly conserved across actinomycetes. In turn, GlnR controls the catalytic and regulatory activities (intracellular acetylation levels) of glutamine synthetases at the transcriptional and posttranslational levels, indicating an autofeedback loop that regulates nitrogen metabolism in response to environmental change. Thus, this GlnR-mediated acetylation pathway provides a signaling cascade that acts from nutrient sensing to acetylation of proteins to feedback regulation. This work presents significant new insights at the molecular level into the mechanisms underlying the regulation of protein acetylation and nitrogen metabolism in actinomycetes. PMID:27247389

  7. Proteome-wide analysis of lysine acetylation in the plant pathogen Botrytis cinerea.

    PubMed

    Lv, Binna; Yang, Qianqian; Li, Delong; Liang, Wenxing; Song, Limin

    2016-01-01

    Lysine acetylation is a dynamic and reversible post-translational modification that plays an important role in diverse cellular processes. Botrytis cinerea is the most thoroughly studied necrotrophic species due to its broad host range and huge economic impact. However, to date, little is known about the functions of lysine acetylation in this plant pathogen. In this study, we determined the lysine acetylome of B. cinerea through the combination of affinity enrichment and high-resolution LC-MS/MS analysis. Overall, 1582 lysine acetylation sites in 954 proteins were identified. Bioinformatics analysis shows that the acetylated proteins are involved in diverse biological functions and show multiple cellular localizations. Several particular amino acids preferred near acetylation sites, including K(ac)Y, K(ac)H, K(ac)***R, K(ac)F, FK(ac) and K(ac)***K, were identified in this organism. Protein interaction network analysis demonstrates that a variety of interactions are modulated by protein acetylation. Interestingly, 6 proteins involved in virulence of B. cinerea, including 3 key components of the high-osmolarity glycerol pathway, were found to be acetylated, suggesting that lysine acetylation plays regulatory roles in pathogenesis. These data provides the first comprehensive view of the acetylome of B. cinerea and serves as a rich resource for functional analysis of lysine acetylation in this plant pathogen. PMID:27381557

  8. Proteome-wide analysis of lysine acetylation in the plant pathogen Botrytis cinerea

    PubMed Central

    Lv, Binna; Yang, Qianqian; Li, Delong; Liang, Wenxing; Song, Limin

    2016-01-01

    Lysine acetylation is a dynamic and reversible post-translational modification that plays an important role in diverse cellular processes. Botrytis cinerea is the most thoroughly studied necrotrophic species due to its broad host range and huge economic impact. However, to date, little is known about the functions of lysine acetylation in this plant pathogen. In this study, we determined the lysine acetylome of B. cinerea through the combination of affinity enrichment and high-resolution LC-MS/MS analysis. Overall, 1582 lysine acetylation sites in 954 proteins were identified. Bioinformatics analysis shows that the acetylated proteins are involved in diverse biological functions and show multiple cellular localizations. Several particular amino acids preferred near acetylation sites, including KacY, KacH, Kac***R, KacF, FKac and Kac***K, were identified in this organism. Protein interaction network analysis demonstrates that a variety of interactions are modulated by protein acetylation. Interestingly, 6 proteins involved in virulence of B. cinerea, including 3 key components of the high-osmolarity glycerol pathway, were found to be acetylated, suggesting that lysine acetylation plays regulatory roles in pathogenesis. These data provides the first comprehensive view of the acetylome of B. cinerea and serves as a rich resource for functional analysis of lysine acetylation in this plant pathogen. PMID:27381557

  9. Comparative analysis of pharmacological treatments with N-acetyl-dl-leucine (Tanganil) and its two isomers (N-acetyl-L-leucine and N-acetyl-D-leucine) on vestibular compensation: Behavioral investigation in the cat.

    PubMed

    Tighilet, Brahim; Leonard, Jacques; Bernard-Demanze, Laurence; Lacour, Michel

    2015-12-15

    Head roll tilt, postural imbalance and spontaneous nystagmus are the main static vestibular deficits observed after an acute unilateral vestibular loss (UVL). In the UVL cat model, these deficits are fully compensated over 6 weeks as the result of central vestibular compensation. N-Acetyl-dl-leucine is a drug prescribed in clinical practice for the symptomatic treatment of acute UVL patients. The present study investigated the effects of N-acetyl-dl-leucine on the behavioral recovery after unilateral vestibular neurectomy (UVN) in the cat, and compared the effects of each of its two isomers N-acetyl-L-leucine and N-acetyl-D-leucine. Efficacy of these three drug treatments has been evaluated with respect to a placebo group (UVN+saline water) on the global sensorimotor activity (observation grids), the posture control (support surface measurement), the locomotor balance (maximum performance at the rotating beam test), and the spontaneous vestibular nystagmus (recorded in the light). Whatever the parameters tested, the behavioral recovery was strongly and significantly accelerated under pharmacological treatments with N-acetyl-dl-leucine and N-acetyl-L-leucine. In contrast, the N-acetyl-D-leucine isomer had no effect at all on the behavioral recovery, and animals of this group showed the same recovery profile as those receiving a placebo. It is concluded that the N-acetyl-L-leucine isomer is the active part of the racemate component since it induces a significant acceleration of the vestibular compensation process similar (and even better) to that observed under treatment with the racemate component only. PMID:26607469

  10. The Metabolic Fate of Deoxynivalenol and Its Acetylated Derivatives in a Wheat Suspension Culture: Identification and Detection of DON-15-O-Glucoside, 15-Acetyl-DON-3-O-Glucoside and 15-Acetyl-DON-3-Sulfate.

    PubMed

    Schmeitzl, Clemens; Warth, Benedikt; Fruhmann, Philipp; Michlmayr, Herbert; Malachová, Alexandra; Berthiller, Franz; Schuhmacher, Rainer; Krska, Rudolf; Adam, Gerhard

    2015-08-01

    Deoxynivalenol (DON) is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON) and 3,15-diacetyl-DON (3,15-diADON), and monitored the metabolization over a course of 96 h. Supernatant and cell extract samples were analyzed using a tailored LC-MS/MS method for the quantification of DON metabolites. We report the formation of tentatively identified DON-15-O-β-D-glucoside (D15G) and of 15-acetyl-DON-3-sulfate (15-ADON3S) as novel deoxynivalenol metabolites in wheat. Furthermore, we found that the recently identified 15-acetyl-DON-3-O-β-D-glucoside (15-ADON3G) is the major metabolite produced after 15-ADON challenge. 3-ADON treatment led to a higher intracellular content of toxic metabolites after six hours compared to all other treatments. 3-ADON was exclusively metabolized into DON before phase II reactions occurred. In contrast, we found that 15-ADON was directly converted into 15-ADON3G and 15-ADON3S in addition to metabolization into deoxynivalenol-3-O-β-D-glucoside (D3G). This study highlights significant differences in the metabolization of DON and its acetylated derivatives. PMID:26274975

  11. The Metabolic Fate of Deoxynivalenol and Its Acetylated Derivatives in a Wheat Suspension Culture: Identification and Detection of DON-15-O-Glucoside, 15-Acetyl-DON-3-O-Glucoside and 15-Acetyl-DON-3-Sulfate

    PubMed Central

    Schmeitzl, Clemens; Warth, Benedikt; Fruhmann, Philipp; Michlmayr, Herbert; Malachová, Alexandra; Berthiller, Franz; Schuhmacher, Rainer; Krska, Rudolf; Adam, Gerhard

    2015-01-01

    Deoxynivalenol (DON) is a protein synthesis inhibitor produced by the Fusarium species, which frequently contaminates grains used for human or animal consumption. We treated a wheat suspension culture with DON or one of its acetylated derivatives, 3-acetyl-DON (3-ADON), 15-acetyl-DON (15-ADON) and 3,15-diacetyl-DON (3,15-diADON), and monitored the metabolization over a course of 96 h. Supernatant and cell extract samples were analyzed using a tailored LC-MS/MS method for the quantification of DON metabolites. We report the formation of tentatively identified DON-15-O-β-D-glucoside (D15G) and of 15-acetyl-DON-3-sulfate (15-ADON3S) as novel deoxynivalenol metabolites in wheat. Furthermore, we found that the recently identified 15-acetyl-DON-3-O-β-D-glucoside (15-ADON3G) is the major metabolite produced after 15-ADON challenge. 3-ADON treatment led to a higher intracellular content of toxic metabolites after six hours compared to all other treatments. 3-ADON was exclusively metabolized into DON before phase II reactions occurred. In contrast, we found that 15-ADON was directly converted into 15-ADON3G and 15-ADON3S in addition to metabolization into deoxynivalenol-3-O-β-D-glucoside (D3G). This study highlights significant differences in the metabolization of DON and its acetylated derivatives. PMID:26274975

  12. Biobreeding rat islets exhibit reduced antioxidative defense and N-acetyl cysteine treatment delays type 1 diabetes

    PubMed Central

    Bogdani, Marika; Henschel, Angela M.; Kansra, Sanjay; Fuller, Jessica M.; Geoffrey, Rhonda; Jia, Shuang; Kaldunski, Mary L.; Pavletich, Scott; Prosser, Simon; Chen, Yi-Guang; Lernmark, Åke; Hessner, Martin J.

    2014-01-01

    Islet-level oxidative stress has been proposed as a trigger for type 1 diabetes (T1D), and release of cytokines by infiltrating immune cells further elevates reactive oxygen species (ROS), exacerbating β cell duress. To identify genes/mechanisms involved with diabeto-genesis at the β cell level, gene expression profiling and targeted follow-up studies were used to investigate islet activity in the biobreeding (BB) rat. Forty-day-old spontaneously diabetic lymphopenic BB DRlyp/lyp rats (before T cell insulitis) as well as nondiabetic BB DR+/+ rats, nondiabetic but lymphopenic F344lyp/lyp rats, and healthy Fischer (F344) rats were examined. Gene expression profiles of BB rat islets were highly distinct from F344 islets and under-expressed numerous genes involved in ROS metabolism, including glutathione S-transferase (GST) family members (Gstm2, Gstm4, Gstm7, Gstt1, Gstp1, and Gstk1), superoxide dismutases (Sod2 and Sod3), peroxidases, and peroxiredoxins. This pattern of under-expression was not observed in brain, liver, or muscle. Compared with F344 rats, BB rat pancreata exhibited lower GST protein levels, while plasma GST activity was found significantly lower in BB rats. Systemic administration of the antioxidant N-acetyl cysteine to DRlyp/lyp rats altered abundances of peripheral eosinophils, reduced severity of insulitis, and significantly delayed but did not prevent diabetes onset. We find evidence of β cell dysfunction in BB rats independent of T1D progression, which includes lower expression of genes related to antioxidative defense mechanisms during the pre-onset period that may contribute to overall T1D susceptibility. PMID:23111281

  13. Effect of Acetyl-L-Carnitine on Antioxidant Status, Lipid Peroxidation, and Oxidative Damage of Arsenic in Rat.

    PubMed

    Sepand, Mohammad Reza; Razavi-Azarkhiavi, Kamal; Omidi, Ameneh; Zirak, Mohammad Reza; Sabzevari, Samin; Kazemi, Ali Reza; Sabzevari, Omid

    2016-05-01

    Arsenic (As) is a widespread environmental contaminant present around the world in both organic and inorganic forms. Oxidative stress is postulated as the main mechanism for As-induced toxicity. This study was planned to examine the protective effect of acetyl-L-carnitine (ALC) on As-induced oxidative damage in male rats. Animals were randomly divided into four groups of control (saline), sodium arsenite (NaAsO2, 20 mg/kg), ALC (300 mg/kg), and NaAsO2 plus ALC. Animals were dosed orally for 28 successive days. Blood and tissue samples including kidney, brain, liver, heart, and lung were collected on the 28th day and evaluated for oxidative damage and histological changes. NaAsO2 exposure caused a significant lipid peroxidation as evidenced by elevation in thiobarbituric acid-reactive substances (TBARS). The activity of antioxidant enzymes such as glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), as well as sulfhydryl group content (SH group) was significantly suppressed in various organs following NaAsO2 treatment (P < 0.05). Furthermore, NaAsO2 administration increased serum values of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and bilirubin. Our findings revealed that co-administration of ALC and NaAsO2 significantly suppressed the oxidative damage induced by NaAsO2. Tissue histological studies have confirmed the biochemical findings and provided evidence for the beneficial role of ALC. The results concluded that ALC attenuated NaAsO2-induced toxicity, and this protective effect may result from the ability of ALC in maintaining oxidant-antioxidant balance. PMID:26349760

  14. Structure-Based Design of Inhibitors of the Crucial Cysteine Biosynthetic Pathway Enzyme O-Acetyl Serine Sulfhydrylase.

    PubMed

    Mazumder, Mohit; Gourinath, Samudrala

    2016-01-01

    The cysteine biosynthetic pathway is of fundamental importance for the growth, survival, and pathogenicity of the many pathogens. This pathway is present in many species but is absent in mammals. The ability of pathogens to counteract the oxidative defences of a host is critical for the survival of these pathogens during their long latent phases, especially in anaerobic pathogens such as Entamoeba histolytica, Leishmania donovani, Trichomonas vaginalis, and Salmonella typhimurium. All of these organisms rely on the de novo cysteine biosynthetic pathway to assimilate sulphur and maintain a ready supply of cysteine. The de novo cysteine biosynthetic pathway, on account of its being important for the survival of pathogens and at the same time being absent in mammals, is an important drug target for diseases such as amoebiasis, trichomoniasis & tuberculosis. Cysteine biosynthesis is catalysed by two enzymes: serine acetyl transferase (SAT) followed by O-acetylserine sulfhydrylase (OASS). OASS is well studied, and with the availability of crystal structures of this enzyme in different conformations, it is a suitable template for structure-based inhibitor development. Moreover, OASS is highly conserved, both structurally and sequence-wise, among the above-mentioned organisms. There have been several reports of inhibitor screening and development against this enzyme from different organisms such as Salmonella typhimurium, Mycobacterium tuberculosis and Entamoeba histolytica. All of these inhibitors have been reported to display micromolar to nanomolar binding affinities for the open conformation of the enzyme. In this review, we highlight the structural similarities of this enzyme in different organisms and the attempts for inhibitor development so far. We also propose that the intermediate state of the enzyme may be the ideal target for the design of effective highaffinity inhibitors. PMID:26303427

  15. The dynamic organization of fungal acetyl-CoA carboxylase

    PubMed Central

    Hunkeler, Moritz; Stuttfeld, Edward; Hagmann, Anna; Imseng, Stefan; Maier, Timm

    2016-01-01

    Acetyl-CoA carboxylases (ACCs) catalyse the committed step in fatty-acid biosynthesis: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. They are important regulatory hubs for metabolic control and relevant drug targets for the treatment of the metabolic syndrome and cancer. Eukaryotic ACCs are single-chain multienzymes characterized by a large, non-catalytic central domain (CD), whose role in ACC regulation remains poorly characterized. Here we report the crystal structure of the yeast ACC CD, revealing a unique four-domain organization. A regulatory loop, which is phosphorylated at the key functional phosphorylation site of fungal ACC, wedges into a crevice between two domains of CD. Combining the yeast CD structure with intermediate and low-resolution data of larger fragments up to intact ACCs provides a comprehensive characterization of the dynamic fungal ACC architecture. In contrast to related carboxylases, large-scale conformational changes are required for substrate turnover, and are mediated by the CD under phosphorylation control. PMID:27073141

  16. Protein acetylation sites mediated by Schistosoma mansoni GCN5

    SciTech Connect

    Moraes Maciel, Renata de; Furtado Madeiro da Costa, Rodrigo; Meirelles Bastosde Oliveira, Francisco; Rumjanek, Franklin David; Fantappie, Marcelo Rosado

    2008-05-23

    The transcriptional co-activator GCN5, a histone acetyltransferase (HAT), is part of large multimeric complexes that are required for chromatin remodeling and transcription activation. As in other eukaryotes, the DNA from the parasite Schistosome mansoni is organized into nucleosomes and the genome encodes components of chromatin-remodeling complexes. Using a series of synthetic peptides we determined that Lys-14 of histone H3 was acetylated by the recombinant SmGCN5-HAT domain. SmGCN5 was also able to acetylate schistosome non-histone proteins, such as the nuclear receptors SmRXR1 and SmNR1, and the co-activator SmNCoA-62. Electron microscopy revealed the presence of SmGCN5 protein in the nuclei of vitelline cells. Within the nucleus, SmGCN5 was found to be located in interchromatin granule clusters (IGCs), which are transcriptionally active structures. The data suggest that SmGCN5 is involved in transcription activation.

  17. Microtubule acetylation promotes kinesin-1 binding and transport.

    PubMed

    Reed, Nathan A; Cai, Dawen; Blasius, T Lynne; Jih, Gloria T; Meyhofer, Edgar; Gaertig, Jacek; Verhey, Kristen J

    2006-11-01

    Long-distance intracellular delivery is driven by kinesin and dynein motor proteins that ferry cargoes along microtubule tracks . Current models postulate that directional trafficking is governed by known biophysical properties of these motors-kinesins generally move to the plus ends of microtubules in the cell periphery, whereas cytoplasmic dynein moves to the minus ends in the cell center. However, these models are insufficient to explain how polarized protein trafficking to subcellular domains is accomplished. We show that the kinesin-1 cargo protein JNK-interacting protein 1 (JIP1) is localized to only a subset of neurites in cultured neuronal cells. The mechanism of polarized trafficking appears to involve the preferential recognition of microtubules containing specific posttranslational modifications (PTMs) by the kinesin-1 motor domain. Using a genetic approach to eliminate specific PTMs, we show that the loss of a single modification, alpha-tubulin acetylation at Lys-40, influences the binding and motility of kinesin-1 in vitro. In addition, pharmacological treatments that increase microtubule acetylation cause a redirection of kinesin-1 transport of JIP1 to nearly all neurite tips in vivo. These results suggest that microtubule PTMs are important markers of distinct microtubule populations and that they act to control motor-protein trafficking. PMID:17084703

  18. The dynamic organization of fungal acetyl-CoA carboxylase.

    PubMed

    Hunkeler, Moritz; Stuttfeld, Edward; Hagmann, Anna; Imseng, Stefan; Maier, Timm

    2016-01-01

    Acetyl-CoA carboxylases (ACCs) catalyse the committed step in fatty-acid biosynthesis: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. They are important regulatory hubs for metabolic control and relevant drug targets for the treatment of the metabolic syndrome and cancer. Eukaryotic ACCs are single-chain multienzymes characterized by a large, non-catalytic central domain (CD), whose role in ACC regulation remains poorly characterized. Here we report the crystal structure of the yeast ACC CD, revealing a unique four-domain organization. A regulatory loop, which is phosphorylated at the key functional phosphorylation site of fungal ACC, wedges into a crevice between two domains of CD. Combining the yeast CD structure with intermediate and low-resolution data of larger fragments up to intact ACCs provides a comprehensive characterization of the dynamic fungal ACC architecture. In contrast to related carboxylases, large-scale conformational changes are required for substrate turnover, and are mediated by the CD under phosphorylation control. PMID:27073141

  19. The dynamic organization of fungal acetyl-CoA carboxylase

    NASA Astrophysics Data System (ADS)

    Hunkeler, Moritz; Stuttfeld, Edward; Hagmann, Anna; Imseng, Stefan; Maier, Timm

    2016-04-01

    Acetyl-CoA carboxylases (ACCs) catalyse the committed step in fatty-acid biosynthesis: the ATP-dependent carboxylation of acetyl-CoA to malonyl-CoA. They are important regulatory hubs for metabolic control and relevant drug targets for the treatment of the metabolic syndrome and cancer. Eukaryotic ACCs are single-chain multienzymes characterized by a large, non-catalytic central domain (CD), whose role in ACC regulation remains poorly characterized. Here we report the crystal structure of the yeast ACC CD, revealing a unique four-domain organization. A regulatory loop, which is phosphorylated at the key functional phosphorylation site of fungal ACC, wedges into a crevice between two domains of CD. Combining the yeast CD structure with intermediate and low-resolution data of larger fragments up to intact ACCs provides a comprehensive characterization of the dynamic fungal ACC architecture. In contrast to related carboxylases, large-scale conformational changes are required for substrate turnover, and are mediated by the CD under phosphorylation control.

  20. Two Arabidopsis Proteins Synthesize Acetylated Xylan in Vitro

    PubMed Central

    Urbanowicz, Breeanna R.; Peña, Maria J.; Moniz, Heather A.; Moremen, Kelley W.; York, William S.

    2014-01-01

    SUMMARY Xylan is the third most abundant glycopolymer on earth after cellulose and chitin. As a major component of wood, grain and forage, this natural biopolymer has far-reaching impacts on human life. This highly acetylated cell wall polysaccharide is a vital component of the plant cell wall, which functions as a molecular scaffold, providing plants with mechanical strength and flexibility. Mutations that impair synthesis of the xylan backbone give rise to plants that fail to grow normally due to collapsed xylem cells in the vascular system. Phenotypic analysis of these mutants has implicated many proteins in xylan biosynthesis. However, the enzymes directly responsible for elongation and acetylation of the xylan backbone have not been unambiguously identified. Here we provide direct biochemical evidence that two Arabidopsis thaliana proteins, IRREGULAR XYLEM 10-L (IRX10-L) and ESKIMO1/ TRICOME BIREFRINGENCE 29 (ESK1/TBL29), catalyze these respective processes in vitro. By identifying the elusive xylan synthase and establishing ESK1/TBL29 as the archetypal plant polysaccharide O-acetyltransferase, we have resolved two long-standing questions in plant cell wall biochemistry. These findings shed light on integral steps in the molecular pathways utilized by plants to synthesize a major component of the world's biomass and expand our toolkit for producing glycopolymers with valuable properties. PMID:25141999

  1. Preparation and characterization of N-benzoyl-O-acetyl-chitosan.

    PubMed

    Cai, Jinping; Dang, Qifeng; Liu, Chengsheng; Fan, Bing; Yan, Jingquan; Xu, Yanyan; Li, Jingjing

    2015-01-01

    A novel amphipathic chitosan derivative, N-benzoyl-O-acetyl-chitosan (BACS), was prepared by using the selective partial acylation of chitosan (CS), benzoyl chloride, and acetic acid under high-intensity ultrasound. The chemical structure and physical properties of BACS were characterized by FTIR, (1)H NMR, TGA, and XRD techniques. The degrees of substitution of benzoyl and acetyl for the chitosan derivatives were 0.26 and 1.15, respectively, which were calculated from the peak areas in NMR spectra by using the combined integral methods. The foaming properties of CS and BACS were determined and the results suggested BACS had better foam capacity and stability than those of chitosan. In addition, the antimicrobial activities of CS and BACS were also investigated against two species of bacteria (Escherichia coli and Staphylococcus aureus) and a fungus (Aspergillus niger), the results indicated that the antibacterial and antifungal activities of BACS were much stronger than those of the parent chitosan. These findings suggested that BACS was preferable for use as a food additive with a dual role of both foaming agent and food preservative. PMID:25783016

  2. Polymorphic acetylation of arylamines and DNA-adduct formation.

    PubMed

    Weber, W W; Levy, G N; Martell, K J

    1990-01-01

    Inbred mouse strains congenic for rapid and slow N-acetyltransferase (NAT) (A.B6, rapid and B6.A, slow) were used to separate the effect of the NAT polymorphism from the influence of other genetically polymorphic enzymes on DNA adduct formation induced by exposure to arylamine carcinogens. Adduct formation was measured by HPLC analysis of 32P-postlabeled nucleotides from DNA of the urinary bladder and liver. Acetylator phenotype was a significant determinant of DNA damage in females as slow acetylators had higher levels of bladder DNA adducts than rapids. This correlation was the reverse of that seen with liver DNA. Older mice (20-23 weeks) formed much higher bladder DNA adduct levels than young mice (7 week). The increase in bladder adduct formation with age was seen in both sexes of all mouse strains. The older male B6 mice showed a 26-fold increase in bladder adducts and the older females showed no more than a 2-fold increase. In addition, the older male B6 mice produced significant amounts of an unidentified, early eluting adduct peak. Biochemical studies of liver NAT and O-acetyltransferase (OAT) activities showed a direct correlation between the levels of liver 2-aminofluorene (AF) NAT activity and levels of liver DNA-adduct formation, but the role of OAT activity in adduct formation in the mouse remains unclear. These results indicate that the NAT phenotype, age and sex are all important determinants of arylamine-DNA adduct formation in mice. PMID:2134671

  3. Autotrophic acetyl coenzyme A biosynthesis in Methanococcus maripaludis.

    PubMed Central

    Shieh, J; Whitman, W B

    1988-01-01

    To detect autotrophic CO2 assimilation in cell extracts of Methanococcus maripaludis, lactate dehydrogenase and NADH were added to convert pyruvate formed from autotrophically synthesized acetyl coenzyme A to lactate. The lactate produced was determined spectrophotometrically. When CO2 fixation was pulled in the direction of lactate synthesis, CO2 reduction to methane was inhibited. Bromoethanesulfonate (BES), a potent inhibitor of methanogenesis, enhanced lactate synthesis, and methyl coenzyme M inhibited it in the absence of BES. Lactate synthesis was dependent on CO2 and H2, but H2 + CO2-independent synthesis was also observed. In cell extracts, the rate of lactate synthesis was about 1.2 nmol min-1 mg of protein-1. When BES was added, the rate of lactate synthesis increased to 2.3 nmol min-1 mg of protein-1. Because acetyl coenzyme A did not stimulate lactate synthesis, pyruvate synthase may have been the limiting activity in these assays. Radiolabel from 14CO2 was incorporated into lactate. The percentages of radiolabel in the C-1, C-2, and C-3 positions of lactate were 73, 33, and 11%, respectively. Both carbon monoxide and formaldehyde stimulated lactate synthesis. 14CH2O was specifically incorporated into the C-3 of lactate, and 14CO was incorporated into the C-1 and C-2 positions. Low concentrations of cyanide also inhibited autotrophic growth, CO dehydrogenase activity, and autotrophic lactate synthesis. These observations are in agreement with the acetogenic pathway of autotrophic CO2 assimilation. PMID:3133359

  4. Identification and characteristics of the structural gene for the Drosophila eye colour mutant sepia, encoding PDA synthase, a member of the omega class glutathione S-transferases.

    PubMed

    Kim, Jaekwang; Suh, Hyunsuk; Kim, Songhee; Kim, Kiyoung; Ahn, Chiyoung; Yim, Jeongbin

    2006-09-15

    The eye colour mutant sepia (se1) is defective in PDA {6-acetyl-2-amino-3,7,8,9-tetrahydro-4H-pyrimido[4,5-b]-[1,4]diazepin-4-one or pyrimidodiazepine} synthase involved in the conversion of 6-PTP (2-amino-4-oxo-6-pyruvoyl-5,6,7,8-tetrahydropteridine; also known as 6-pyruvoyltetrahydropterin) into PDA, a key intermediate in drosopterin biosynthesis. However, the identity of the gene encoding this enzyme, as well as its molecular properties, have not yet been established. Here, we identify and characterize the gene encoding PDA synthase and show that it is the structural gene for sepia. Based on previously reported information [Wiederrecht, Paton and Brown (1984) J. Biol. Chem. 259, 2195-2200; Wiederrecht and Brown (1984) J. Biol. Chem. 259, 14121-14127; Andres (1945) Drosoph. Inf. Serv. 19, 45; Ingham, Pinchin, Howard and Ish-Horowicz (1985) Genetics 111, 463-486; Howard, Ingham and Rushlow (1988) Genes Dev. 2, 1037-1046], we isolated five candidate genes predicted to encode GSTs (glutathione S-transferases) from the presumed sepia locus (region 66D5 on chromosome 3L). All cloned and expressed candidates exhibited relatively high thiol transferase and dehydroascorbate reductase activities and low activity towards 1-chloro-2,4-dinitrobenzene, characteristic of Omega class GSTs, whereas only CG6781 catalysed the synthesis of PDA in vitro. The molecular mass of recombinant CG6781 was estimated to be 28 kDa by SDS/PAGE and 56 kDa by gel filtration, indicating that it is a homodimer under native conditions. Sequencing of the genomic region spanning CG6781 revealed that the se1 allele has a frameshift mutation from 'AAGAA' to 'GTG' at nt 190-194, and that this generates a premature stop codon. Expression of the CG6781 open reading frame in an se1 background rescued the eye colour defect as well as PDA synthase activity and drosopterins content. The extent of rescue was dependent on the dosage of transgenic CG6781. In conclusion, we have discovered a new catalytic

  5. Hepatocyte nuclear factor-1alpha is required for expression but dispensable for histone acetylation of the lactase-phlorizin hydrolase gene in vivo.

    PubMed

    Bosse, Tjalling; van Wering, Herbert M; Gielen, Marieke; Dowling, Lauren N; Fialkovich, John J; Piaseckyj, Christina M; Gonzalez, Frank J; Akiyama, Taro E; Montgomery, Robert K; Grand, Richard J; Krasinski, Stephen D

    2006-05-01

    Hepatocyte nuclear factor-1alpha (HNF-1alpha) is a modified homeodomain-containing transcription factor that has been implicated in the regulation of intestinal genes. To define the importance and underlying mechanism of HNF-1alpha for the regulation of intestinal gene expression in vivo, we analyzed the expression of the intestinal differentiation markers and putative HNF-1alpha targets lactase-phlorizin hydrolase (LPH) and sucrase-isomaltase (SI) in hnf1alpha null mice. We found that in adult jejunum, LPH mRNA in hnf1alpha(-/-) mice was reduced 95% compared with wild-type controls (P < 0.01, n = 4), whereas SI mRNA was virtually identical to that in wild-type mice. Furthermore, SI mRNA abundance was unchanged in the absence of HNF-1alpha along the length of the adult mouse small intestine as well as in newborn jejunum. We found that HNF-1alpha occupies the promoters of both the LPH and SI genes in vivo. However, in contrast to liver and pancreas, where HNF-1alpha regulates target genes by recruitment of histone acetyl transferase activity to the promoter, the histone acetylation state of the LPH and SI promoters was not affected by the presence or absence of HNF-1alpha. Finally, we showed that a subset of hypothesized intestinal target genes is regulated by HNF-1alpha in vivo and that this regulation occurs in a defined tissue-specific and developmental context. These data indicate that HNF-1alpha is an activator of a subset of intestinal genes and induces these genes through an alternative mechanism in which it is dispensable for chromatin remodeling. PMID:16223943

  6. Mutations of Arabidopsis TBL32 and TBL33 Affect Xylan Acetylation and Secondary Wall Deposition

    PubMed Central

    Yuan, Youxi; Teng, Quincy; Zhong, Ruiqin; Haghighat, Marziyeh; Richardson, Elizabeth A.; Ye, Zheng-Hua

    2016-01-01

    Xylan is a major acetylated polymer in plant lignocellulosic biomass and it can be mono- and di-acetylated at O-2 and O-3 as well as mono-acetylated at O-3 of xylosyl residues that is substituted with glucuronic acid (GlcA) at O-2. Based on the finding that ESK1, an Arabidopsis thaliana DUF231 protein, specifically mediates xylan 2-O- and 3-O-monoacetylation, we previously proposed that different acetyltransferase activities are required for regiospecific acetyl substitutions of xylan. Here, we demonstrate the functional roles of TBL32 and TBL33, two ESK1 close homologs, in acetyl substitutions of xylan. Simultaneous mutations of TBL32 and TBL33 resulted in a significant reduction in xylan acetyl content and endoxylanase digestion of the mutant xylan released GlcA-substituted xylooligomers without acetyl groups. Structural analysis of xylan revealed that the tbl32 tbl33 mutant had a nearly complete loss of 3-O-acetylated, 2-O-GlcA-substituted xylosyl residues. A reduction in 3-O-monoacetylated and 2,3-di-O-acetylated xylosyl residues was also observed. Simultaneous mutations of TBL32, TBL33 and ESK1 resulted in a severe reduction in xylan acetyl level down to 15% of that of the wild type, and concomitantly, severely collapsed vessels and stunted plant growth. In particular, the S2 layer of secondary walls in xylem vessels of tbl33 esk1 and tbl32 tbl33 esk1 exhibited an altered structure, indicating abnormal assembly of secondary wall polymers. These results demonstrate that TBL32 and TBL33 play an important role in xylan acetylation and normal deposition of secondary walls. PMID:26745802

  7. Mutations of Arabidopsis TBL32 and TBL33 affect xylan acetylation and secondary wall deposition

    DOE PAGESBeta

    Yuan, Youxi; Teng, Quincy; Zhong, Ruiqin; Haghighat, Marziyeh; Richardson, Elizabeth A.; Ye, Zheng -Hua; Zhang, Jin -Song

    2016-01-08

    Xylan is a major acetylated polymer in plant lignocellulosic biomass and it can be monoand di-acetylated at O-2 and O-3 as well as mono-acetylated at O-3 of xylosyl residues that is substituted with glucuronic acid (GlcA) at O-2. Based on the finding that ESK1, an Arabidopsis thaliana DUF231 protein, specifically mediates xylan 2-O- and 3-O-monoacetylation, we previously proposed that different acetyltransferase activities are required for regiospecific acetyl substitutions of xylan. Here, we demonstrate the functional roles of TBL32 and TBL33, two ESK1 close homologs, in acetyl substitutions of xylan. Simultaneous mutations of TBL32 and TBL33 resulted in a significant reductionmore » in xylan acetyl content and endoxylanase digestion of the mutant xylan released GlcA-substituted xylooligomers without acetyl groups. Structural analysis of xylan revealed that the tbl32 tbl33 mutant had a nearly complete loss of 3-O-acetylated, 2-O-GlcA-substituted xylosyl residues. A reduction in 3-Omonoacetylated and 2,3-di-O-acetylated xylosyl residues was also observed. Simultaneous mutations of TBL32, TBL33 and ESK1 resulted in a severe reduction in xylan acetyl level down to 15% of that of the wild type, and concomitantly, severely collapsed vessels and stunted plant growth. In particular, the S2 layer of secondary walls in xylem vessels of tbl33 esk1 and tbl32 tbl33 esk1 exhibited an altered structure, indicating abnormal assembly of secondary wall polymers. Furthermore, these results demonstrate that TBL32 and TBL33 play an important role in xylan acetylation and normal deposition of secondary walls.« less

  8. Generation of mature Nα-terminal acetylated thymosin α 1 by cleavage of recombinant prothymosin α.

    PubMed

    Liu, Bo; Gong, Xin; Chang, Shaohong; Sun, Peng; Wu, Jun

    2013-01-01

    N(α)-terminal acetylation of peptides plays an important biological role but is rarely observed in prokaryotes. N(α)-terminal acetylated thymosin α1 (Tα1), a 28-amino-acid peptide, is an immune modifier that has been used in the clinic to treat hepatitis B and C virus (HBV/HCV) infections. We previously documented N(α)-terminal acetylation of recombinant prothymosin α (ProTα) in E. coli. Here we present a method for production of N(α)-acetylated Tα1 from recombinant ProTα. The recombinant ProTα was cleaved by human legumain expressed in Pichia pastoris to release Tα1 in vitro. The N(α)-acetylated Tα1 peptide was subsequently purified by reverse phase and cation exchange chromatography. Mass spectrometry indicated that the molecular mass of recombinant N(α)-acetylated Tα1 was 3108.79 in, which is identical to the mass of N(α)-acetylated Tα1 produced by total chemical synthesis. This mass corresponded to the nonacetylated Tα1 mass with a 42 Da increment. The retention time of recombinant N(α)-acetylated Tα1 and chemosynthetic N(α)-acetylated Tα1 were both 15.4 min in RP-high performance liquid chromatography (HPLC). These data support the use of an E. coli expression system for the production of recombinant human N(α)-acetylated Tα1 and also will provide the basis for the preparation of recombinant acetylated peptides in E. coli. PMID:24288480

  9. Identification of the Acetylation and Ubiquitin-Modified Proteome during the Progression of Skeletal Muscle Atrophy

    PubMed Central

    Ryder, Daniel J.; Judge, Sarah M.; Beharry, Adam W.; Farnsworth, Charles L.; Silva, Jeffrey C.; Judge, Andrew R.

    2015-01-01

    Skeletal muscle atrophy is a consequence of several physiological and pathophysiological conditions including muscle disuse, aging and diseases such as cancer and heart failure. In each of these conditions, the predominant mechanism contributing to the loss of skeletal muscle mass is increased protein turnover. Two important mechanisms which regulate protein stability and degradation are lysine acetylation and ubiquitination, respectively. However our understanding of the skeletal muscle proteins regulated through acetylation and ubiquitination during muscle atrophy is limited. Therefore, the purpose of the current study was to conduct an unbiased assessment of the acetylation and ubiquitin-modified proteome in skeletal muscle during a physiological condition of muscle atrophy. To induce progressive, physiologically relevant, muscle atrophy, rats were cast immobilized for 0, 2, 4 or 6 days and muscles harvested. Acetylated and ubiquitinated peptides were identified via a peptide IP proteomic approach using an anti-acetyl lysine antibody or a ubiquitin remnant motif antibody followed by mass spectrometry. In control skeletal muscle we identified and mapped the acetylation of 1,326 lysine residues to 425 different proteins and the ubiquitination of 4,948 lysine residues to 1,131 different proteins. Of these proteins 43, 47 and 50 proteins were differentially acetylated and 183, 227 and 172 were differentially ubiquitinated following 2, 4 and 6 days of disuse, respectively. Bioinformatics analysis identified contractile proteins as being enriched among proteins decreased in acetylation and increased in ubiquitination, whereas histone proteins were enriched among proteins increased in acetylation and decreased in ubiquitination. These findings provide the first proteome-wide identification of skeletal muscle proteins exhibiting changes in lysine acetylation and ubiquitination during any atrophy condition, and provide a basis for future mechanistic studies into how the

  10. Acetylation of Gly1 and Lys2 Promotes Aggregation of Human γD-Crystallin

    PubMed Central

    2015-01-01

    The human lens contains three major protein families: α-, β-, and γ-crystallin. Among the several variants of γ-crystallin in the human lens, γD-crystallin is a major form. γD-Crystallin is primarily present in the nuclear region of the lens and contains a single lysine residue at the second position (K2). In this study, we investigated the acetylation of K2 in γD-crystallin in aging and cataractous human lenses. Our results indicated that K2 is acetylated at an early age and that the amount of K2-acetylated γD-crystallin increased with age. Mass spectrometric analysis revealed that in addition to K2, glycine 1 (G1) was acetylated in γD-crystallin from human lenses and in γD-crystallin acetylated in vitro. The chaperone ability of α-crystallin for acetylated γD-crystallin was lower than that for the nonacetylated protein. The tertiary structure and the microenvironment of the cysteine residues were significantly altered by acetylation. The acetylated protein exhibited higher surface hydrophobicity, was unstable against thermal and chemical denaturation, and exhibited a higher propensity to aggregate at 80 °C in comparison to the nonacetylated protein. Acetylation enhanced the GdnHCl-induced unfolding and slowed the subsequent refolding of γD-crystallin. Theoretical analysis indicated that the acetylation of K2 and G1 reduced the structural stability of the protein and brought the distal cysteine residues (C18 and C78) into close proximity. Collectively, these results indicate that the acetylation of G1 and K2 residues in γD-crystallin likely induced a molten globule-like structure, predisposing it to aggregation, which may account for the high content of aggregated proteins in the nucleus of aged and cataractous human lenses. PMID:25393041

  11. A Web-Based Self-Help Intervention With and Without Chat Counseling to Reduce Cannabis Use in Problematic Cannabis Users: Three-Arm Randomized Controlled Trial

    PubMed Central

    Wenger, Andreas; Berg, Oliver; Beck, Thilo; Stark, Lars; Buehler, Eveline; Haug, Severin

    2015-01-01

    Background After alcohol and tobacco, cannabis is the most widely used psychoactive substance in many countries worldwide. Although approximately one in ten users develops serious problems of dependency, only a minority attend outpatient addiction counseling centers. A Web-based intervention could potentially reach those users who hesitate to approach such treatment centers. Objective To test the efficacy of a Web-based self-help intervention with and without chat counseling—Can Reduce—in reducing the cannabis use of problematic cannabis users as an alternative to outpatient treatment services. Methods Altogether, 436 participants were recruited by various online and offline media for the Web-based trial. A total of 308 of these were eligible for study participation and were randomly allocated in an unblinded manner to either self-help with chat (n=114), self-help without chat (n=101), or a waiting list control group (n=93). The fully automated self-help intervention consisted of eight modules designed to reduce cannabis use, and was based on the principles of motivational interviewing, self-control practices, and methods of cognitive behavioral therapy. Additional individual chat counseling sessions were based on the same therapeutic principles. The sessions were conducted by trained counselors and addressed participants' personal problems. The main outcomes were the frequency (number of days) and quantity of cannabis use (number of standardized joints) per week, as entered into the consumption diary at baseline and at the 3-month follow-up. Secondary outcomes included self-reported symptoms of cannabis use disorder, severity of cannabis dependence, risky alcohol use, and mental health symptoms. Intervention participation and retention were extracted from the user progress data and the consumption diary, respectively. Results Can Reduce participants were older (U=2.296, P=.02) and reported a greater number of cannabis use days at baseline than patients who

  12. An Artificial Reaction Promoter Modulates Mitochondrial Functions via Chemically Promoting Protein Acetylation

    PubMed Central

    Shindo, Yutaka; Komatsu, Hirokazu; Hotta, Kohji; Ariga, Katsuhiko; Oka, Kotaro

    2016-01-01

    Acetylation, which modulates protein function, is an important process in intracellular signalling. In mitochondria, protein acetylation regulates a number of enzymatic activities and, therefore, modulates mitochondrial functions. Our previous report showed that tributylphosphine (PBu3), an artificial reaction promoter that promotes acetylransfer reactions in vitro, also promotes the reaction between acetyl-CoA and an exogenously introduced fluorescent probe in mitochondria. In this study, we demonstrate that PBu3 induces the acetylation of mitochondrial proteins and a decrease in acetyl-CoA concentration in PBu3-treated HeLa cells. This indicates that PBu3 can promote the acetyltransfer reaction between acetyl-CoA and mitochondrial proteins in living cells. PBu3-induced acetylation gradually reduced mitochondrial ATP concentrations in HeLa cells without changing the cytoplasmic ATP concentration, suggesting that PBu3 mainly affects mitochondrial functions. In addition, pyruvate, which is converted into acetyl-CoA in mitochondria and transiently increases ATP concentrations in the absence of PBu3, elicited a further decrease in mitochondrial ATP concentrations in the presence of PBu3. Moreover, the application and removal of PBu3 reversibly alternated mitochondrial fragmentation and elongation. These results indicate that PBu3 enhances acetyltransfer reactions in mitochondria and modulates mitochondrial functions in living cells. PMID:27374857

  13. N-Ace: using solvent accessibility and physicochemical properties to identify protein N-acetylation sites.

    PubMed

    Lee, Tzong-Yi; Hsu, Justin Bo-Kai; Lin, Feng-Mao; Chang, Wen-Chi; Hsu, Po-Chiang; Huang, Hsien-Da

    2010-11-30

    Protein acetylation, which is catalyzed by acetyltransferases, is a type of post-translational modification and crucial to numerous essential biological processes, including transcriptional regulation, apoptosis, and cytokine signaling. As the experimental identification of protein acetylation sites is time consuming and laboratory intensive, several computational approaches have been developed for identifying the candidates of experimental validation. In this work, solvent accessibility and the physicochemical properties of proteins are utilized to identify acetylated alanine, glycine, lysine, methionine, serine, and threonine. A two-stage support vector machine was applied to learn the computational models with combinations of amino acid sequences, and the accessible surface area and physicochemical properties of proteins. The predictive accuracy thus achieved is 5% to 14% higher than that of models trained using only amino acid sequences. Additionally, the substrate specificity of the acetylated site was investigated in detail with reference to the subcellular colocalization of acetyltransferases and acetylated proteins. The proposed method, N-Ace, is evaluated using independent test sets in various acetylated residues and predictive accuracies of 90% were achieved, indicating that the performance of N-Ace is comparable with that of other acetylation prediction methods. N-Ace not only provides a user-friendly input/output interface but also is a creative method for predicting protein acetylation sites. This novel analytical resource is now freely available at http://N-Ace.mbc.NCTU.edu.tw/. PMID:20839302

  14. Nε−Lysine Acetylation of a Bacterial Transcription Factor Inhibits Its DNA-Binding Activity

    PubMed Central

    Thao, Sandy; Chen, Chien-Sheng; Zhu, Heng; Escalante-Semerena, Jorge C.

    2010-01-01

    Evidence suggesting that eukaryotes and archaea use reversible Nε-lysine (Nε-Lys) acetylation to modulate gene expression has been reported, but evidence for bacterial use of Nε-Lys acetylation for this purpose is lacking. Here, we report data in support of the notion that bacteria can control gene expression by modulating the acetylation state of transcription factors (TFs). We screened the E. coli proteome for substrates of the bacterial Gcn5-like protein acetyltransferase (Pat). Pat acetylated four TFs, including the RcsB global regulatory protein, which controls cell division, and capsule and flagellum biosynthesis in many bacteria. Pat acetylated residue Lys180 of RcsB, and the NAD+-dependent Sir2 (sirtuin)-like protein deacetylase (CobB) deacetylated acetylated RcsB (RcsBAc), demonstrating that Nε-Lys acetylation of RcsB is reversible. Analysis of RcsBAc and variant RcsB proteins carrying substitutions at Lys180 provided biochemical and physiological evidence implicating Lys180 as a critical residue for RcsB DNA-binding activity. These findings further the likelihood that reversible Nε-Lys acetylation of transcription factors is a mode of regulation of gene expression used by all cells. PMID:21217812

  15. Roles of Arabidopsis TBL34 and TBL35 in xylan acetylation and plant growth.

    PubMed

    Yuan, Youxi; Teng, Quincy; Zhong, Ruiqin; Ye, Zheng-Hua

    2016-02-01

    Xylan is one of the major polymers in lignocellulosic biomass and about 60% of its xylosyl residues are acetylated at O-2 and/or O-3. Because acetylation of cell wall polymers contributes to biomass recalcitrance for biofuel production, it is important to investigate the biochemical mechanism underlying xylan acetylation, the knowledge of which could be applied to custom-design biomass composition tailored for biofuel production. In this report, we investigated the functions of Arabidopsis TRICHOME BIREFRINGENCE-LIKE 34 (TBL34) and TBL35, two DUF231-containing proteins, in xylan acetylation. The TBL34 gene was found to be specifically expressed in xylem cells in stems and root-hypocotyls, and both TBL34 and TBL35 were shown to be localized in the Golgi, where xylan biosynthesis occurs. Chemical analysis revealed that simultaneous mutations of TBL34 and TBL35 caused a mild decrease in xylan acetyl content and a specific reduction in xylan 3-O-monoacetylation and 2,3-di-O-acetylation. Furthermore, simultaneous mutations of TBL34, TBL35 and ESKIMO1 (ESK1) resulted in severely collapsed xylem vessels with altered secondary wall structure, and an extremely retarded plant growth. These findings indicate that TBL34 and TBL35 are putative acetyltransferases required for xylan 3-O-monoacetylation and 2,3-di-O-acetylation and that xylan acetylation is essential for normal secondary wall deposition and plant growth. PMID:26795157

  16. Novel Family of Carbohydrate Esterases, Based on Identification of the Hypocrea jecorina Acetyl Esterase Gene

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant cell walls have been shown to contain acetyl groups in hemicelluloses and pectin. The gene, ae1, encoding the acetyl esterase (Ae1) of Hypocrea jecorina was identified by amino terminal sequencing, peptide mass spectrometry, and genomic sequence analyses. The coded polypeptide had 348 amino ...

  17. The Effect of Acetyl-L-Carnitine Administration on Persons with Down Syndrome

    ERIC Educational Resources Information Center

    Pueschel, Siegfried M.

    2006-01-01

    Since previous investigations reported improvements in cognition of patients with dementia after acetyl-L-carnitine therapy and since there is an increased risk for persons with Down syndrome to develop Alzheimer disease, this study was designed to investigate the effect of acetyl-L-carnitine administration on neurological, intellectual, and…

  18. Histone Acetylation is Recruited in Consolidation as a Molecular Feature of Stronger Memories

    ERIC Educational Resources Information Center

    Federman, Noel; Fustinana, Maria Sol; Romano, Arturo

    2009-01-01

    Gene expression is a key process for memory consolidation. Recently, the participation of epigenetic mechanisms like histone acetylation was evidenced in long-term memories. However, until now the training strength required and the persistence of the chromatin acetylation recruited are not well characterized. Here we studied whether histone…

  19. Polymorphic acetylation of the antibacterials, sulfamethazine and dapsone, in South Indian subjects.

    PubMed

    Peters, J H; Gordon, G R; Karat, A B

    1975-07-01

    A group of South Indian subjects was studied for their capacities to acetylate sulfamethazine (SMZ) and dapsone (DDS) and to clear DDS from the circulation. An apparent trimodal distribution of acetylator phenotypes was found in 49 subjects (51% slow, 12% intermediate, and 37% rapid acetylators) from measurements of the percentage acetylation of SMZ in 6-hour plasma samples after administration of 10 mg SMZ/kg. The intermediate phenotype was not discernible from either the percentage acetylation of SMZ in urine (collected concurrently with the plasma after SMZ) or that of DDS in plasma after the ingestion of 50 mg DDS by the same subjects. The latter two measurements yielded a bimodal distribution of 59% slow and 41% rapid acetylators, nearly identical to earlier reported distributions of isoniazid inactivator phenotypes in larger numbers of South Indian tuberculosis patients. In the current group, acetylation of DDS and SMZ was positively correlated. The half-time of disappearance (T 1/2) of DDS, an expression of the rate of clearance from the plasma, ranged from 13 to 40 hours. No correlation was found between the subject's capacity to acetylate DDS and the T 1/2 value for DDS. These results were generally consistent with earlier observations made during similar studies of American and Filipino subjects. PMID:1155699

  20. Global profiling of lysine acetylation in human histoplasmosis pathogen Histoplasma capsulatum.

    PubMed

    Xie, Longxiang; Fang, Wenjie; Deng, Wanyan; Yu, Zhaoxiao; Li, Juan; Chen, Min; Liao, Wanqing; Xie, Jianping; Pan, Weihua

    2016-04-01

    Histoplasma capsulatum is the causative agent of human histoplasmosis, which can cause respiratory and systemic mycosis in immune-compromised individuals. Lysine acetylation, a protein posttranslational protein modification, is widespread in both eukaryotes and prokaryotes. Although increasing evidence suggests that lysine acetylation may play critical roles in fungus physiology, very little is known about its extent and function in H. capsulatum. To comprehensively profile protein lysine acetylation in H. capsulatum, we performed a global acetylome analysis through peptide prefractionation, antibody enrichment, and LC-MS/MS analysis, identifying 775 acetylation sites on 456 acetylated proteins; and functionally analysis showing their involvement in different biological processes. We defined six types of acetylation site motifs, and the results imply that lysine residue of polypeptide with tyrosine at the -1 and +1 positions, histidine at the +1 position, and phenylalanine (F) at the +1 and +2 position is a preferred substrate of lysine acetyltransferase. Moreover, some virulence factors candidates including calmodulin and DnaK are acetylated. In conclusion, our data set may serve as an important resource for the elucidation of associations between functional protein lysine acetylation and virulence in H. capsulatum. PMID:26806293