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H4
Kinds of H4 Terms modified by H4 Selected AbstractsLithium and KB-R7943 effects on mechanics and energetics of rat heart muscleACTA PHYSIOLOGICA, Issue 1 2002P. Bonazzola ABSTRACT The role of calcium influx on energy expenditure during cardiac contraction was studied. For this purpose, the described ability of lithium and KB-R 7943 (KBR) to diminish Ca entry through Na,Ca exchanger (Ponce-Hornos & Langer, J Mol Cell Cardiol 1980, 12, 1367, Satoh et al., Circulation 2000, 101, 1441) were used. In isolated contractions (contractions elicited after at least 5 min of rest) LiCl 45 mmol L,1 decreased pressure developed and pressure,time integral from 42.3 ± 2.7 and 14.5 ± 1.2 to 32.1 ± 3.4 mN mm,2 and 8.3 ± 0.9 mN mm,2 s, respectively. A similar effect was observed in regular contractions (at 0.16 Hz stimulation). The presence of KBR (5 ,mol L,1) in the perfusate induced a slight but not significant decrease in pressure developed and pressure,time integral in steady-state contractions. As it was previously described, the heat involved in a heart muscle contraction can be decomposed into several components (H1, H2, H3 and H4), but only one (H3) was associated with force generation. While H3 decreased with lithium in both types of contractions, H3/PtI ratio remained unaltered, indicating that the economy for pressure maintenance was unaffected. To further investigate the role of Ca entry on force development, a condition in which the contraction is mainly dependent on extracellular calcium was studied. An ,extra' stimulus applied 200 ms after the regular one in a muscle stimulated at 0.16 Hz induces a contraction with this characteristic (Marengo et al., Am J Physiol 1999, 276, H309). Lithium induced a strong decrease in pressure,time integral and H3 associated with this contraction (43 and 45%, respectively) with no change in H3/PtI ratio. Lithium also reduced (53%) an energy component (H2) associated with Ca cycling. The use of KBR showed qualitatively similar results [i.e. a 33% reduction in pressure,time integral associated with the extrasystole (ES) with no changes in H3/PtI ratio and a 30% reduction in the H2 component]. Li and KBR effects appear to be additive and in the presence of 45 mmol L,1 Li and 5 ,mol L,1 KBR the extrasystole was abolished in 77%. Lithium and KBR effects particularly for the extrasystole can be explained through the inhibition of Ca entry via Na,Ca exchange giving support to the participation of the Na,Ca exchanger in the Ca influx from the extracellular space. In addition, the results also suggest the possibility of an effect of Li on an additional Ca sensitive locus (different than the Na,Ca exchanger). In this connection, in isolated contractions lithium decreased the energy release fraction related to mitochondrial processes (H4) increasing the economy of the overall cardiac contraction. [source] The histone deacetylase inhibitor MS-275 induces p21WAF1/Cip1 expression in human Hep3B hepatoma cellsDRUG DEVELOPMENT RESEARCH, Issue 2 2007Haiyuan Zhang Abstract MS-275 is a novel synthetic benzamide derivative histone deacetylase (HDAC) inhibitor, that has demonstrated antiproliferative activity in a variety of in vitro human cancer cell lines including breast, colon, lung, myeloma, ovary, pancreas, prostate, and leukemia. Currently, little information is available concerning the effects of MS-275 on liver cancer cells. In the current study, MS-275 was found to have potent actions against human hepatoma Hep3B cells including inhibition of cell proliferation and induction of apoptosis. MS-275 selectively up-regulated a cyclin-dependent kinase inhibitor, p21WAF1/Cip1 without alteration of p27WAF1. Expression of p21WAF1/Cip1 is considered to play a pivotal role in Hep3B cell growth arrest and induction of apoptosis. Induction of p21WAF1/Cip1 expression was accompanied by an accumulation of acetylated histones H3 and H4 associated specifically with p21WAF1/Cip1 gene. ChIP analysis revealed remarkable alterations in protein components bound to the promoter region of p21WAF1/Cip1 gene in response to MS-275 treatment. These included the degradation of HDAC1, HDAC3, and c-Myc, and as well as increased p300 and RNA polymerase II. The selective effect of MS-275 on the up-regulation of the p21WAF1/Cip1 gene whose expression was suppressed in the hepatoma cancer cell line indicated that it would be a very attractive approach in clinical liver cancer therapy. Drug Dev Res 68:61,70, 2007. © 2007 Wiley-Liss, Inc. [source] Lectin-based electrophoretic analysis of the expression of the 35,kDa inter-,-trypsin inhibitor heavy chain H4 fragment in sera of patients with five different malignanciesELECTROPHORESIS, Issue 12 2008Emida Mohamed Abstract A 35,kDa glycoprotein whose abundance was previously demonstrated to be enhanced in sera of patients with endometrial adenocarcinoma (n,=,12), was isolated from pooled sera of three of the cancer patients using champedak galactose-binding lectin affinity chromatography in the present study. Subjecting it to 2-DE and MS/MS, the glycoprotein was identified as the O -glycosylated fragment of inter-,-trypsin inhibitor heavy chain H4 (ITIH4). When compared to control sera (n,=,17), expression of the 35,kDa ITIH4 cleavage fragment was demonstrated to be significantly enhanced in sera of patients with breast carcinoma (n,=,10), epithelial ovarian carcinoma (n,=,10), and germ cell ovarian carcinoma (n,=,10) but not in patients with nasopharyngeal carcinoma (n,=,13) and osteosarcoma (n,=,7). The lectin-based electrophoretic bioanalytical method adopted in the present study may be used to assess the physiological relevance of ITIH4 fragmentation and its correlation with different malignancies, their stages and progression. [source] A Dinuclear Double-Stranded Oxido Complex of ReV with a Bis(benzene- o -dithiolato) LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2009Jorge S. Gancheff Abstract The reaction of [ReOCl3(PPh3)2] with 1,2-bis(2,3-dimercaptobenzamido)ethane (H4 - 1) in the presence of Na2CO3 in methanol under anaerobic conditions affords the dinuclear ReV oxido complex [PPh4]2[ReO(1)]2 containing two distorted square-pyramidal {ReVOS4} units bridged by the ligand strands in a double-stranded fashion. The coordinationgeometry around the metal centers is similar to the one observed for [ReO(bdt)2],. The ReS4 planes are arranged in a coplanar fashion and are not twisted around the metal,metal vector, which prevents the complex to adopt a helical structure. Luminescence studies show the presence of emission bands, which are assigned to singlet-singlet transitions exhibiting very fast decays (ca. 10 ns). Theoretical Density Functional (DFT) studies on geometry and electronic properties were performed employing the hybrid B3LYP and PBE1PBE functionals. While the general trends observed in the experimental data are well reproduced in all cases, a good agreement was obtained using PBE1PBE, in particular for the Re,S bonds. Natural Bond Orbitals (NBO) analysis indicates the presence of polarized Re,O and Re,S bonds, both of them polarized toward the non-metal. The calculation show that the molecular orbitals of the ReV are doubly degenerated, the occupied 5d orbital of rhenium lying beneath occupied sulfur-based MOs due to the rigid geometry imposed by the C,C backbone of the bis(benzene- o -dithiolato) ligands. The origin of all absorption bands is ascribed to a ligand-to-metal charge transfer (LMCT), in which occupied sulfur-based orbitals and unoccupied rhenium-centered orbitals are involved.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Size- and Shape-Controlled Synthesis and Assembly of a Silver Nanocomplex in UV-Irradiated TSA SolutionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2006Liangbao Yang Abstract In this paper we describe the size-controlled synthesis ofa silver nanocomplex based on the reduction of silvernitrate (AgNO3) by UV-irradiated tungstosilicate acid [H4(SiW12O40), TSA] solution. This method allows the synthesis of ellipsoidal particles with an average size that is tunable between 2.4 and 84 nm by varying the molar ratio of silver nitrate to TSA, the pH of the reaction solution, and the reaction temperature. Silver nanorods can be formed from the ellipsoidal nanoparticles by controlling the aging time. The formation mechanism of these nanorods is also discussed. The nanoparticles are characterized by UV/Vis spectroscopy, FTIR spectroscopy, XRD analysis, XPS, electron diffraction (ED), TEM, and with a Zetasizer instrument. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Self-Assembly of a Tetranuclear CoIII -Metallacycle from the Reaction of a Bis(benzene- o -dithiolato) Ligand with CoII and Subsequent Aerial OxidationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2006F. Ekkehardt Hahn Abstract The bis(benzene- o -dithiol) ligand [(HS)2 -2,3-C6H3,CH2,C6H3 -2,3-(SH)2] (H4 - 1) reacts, after deprotonation with Li2CO3, with CoCl2·6H2O. Aerial oxidation in methanol gives the tetranuclear metallacycle Li4[Co4(1)4]. The X-ray structure analysis of (PNP)4[Co4(1)4] (7) reveals a cyclic structure in which each of the bis(benzene- o -dithiolato) ligands forms a bridge between two cobalt centers. Two differently coordinated cobalt atoms (syn and anti) are observed in the tetranuclear complex. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Hexaazamacrocycle Containing Pyridine and Its Dicopper Complex as Receptors for Dicarboxylate AnionsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 22 2005Feng Li Abstract The host,guest binding interactions of the hexaazamacrocycle [26]py2N4, in its tetraprotonated form H4[26]py2N44+ as well as in its dicopper(II) complex [Cu2([26]py2N4)(H2O)4]4+, with dicarboxylate anions of different stereoelectronicrequirements, such as oxalate (ox2,), malonate (mal2,), succinate (suc2,), fumarate (fu2,) and maleate (ma2,), were evaluated. The association constants were determined using potentiometric methods in aqueous solution, at 298.0 K and 0.10 mol·dm,3 KCl. These values for the tetraprotonated ditopic receptor with the dicarboxylate anions revealed that the main species in solution corresponds to the formation of {H4[26]py2N4(A)}2+ (pH , 4,9), A being the substrate anion. The values determined are not especially high, but the receptor exhibits selectivity for the malonate anion. The study of the cascade complexes revealed several species in solution, involving mononuclear and dinuclear complexes, mainly protonated and hydrolysed species, as well as the expected complexes [Cu2([26]py2N4)(A)(H2O)x]2+ or [Cu2([26]py2N4)(A)2(H2O)y]. Ox2, and mal2, form cascade complexes with only one anion, which will necessarily bridge the two copper atoms because of the symmetrical arrangement of the dinuclear complex. The two other studied anions, suc2, and ma2,, form species involving two substrate anions, although species with only one suc2, anion were also found. UV/Vis and EPR spectroscopy have shown that the dicopper complex can operate as a sensor to detect and quantitatively determine oxalate spectrophotometrically because of the red shift of the maximum of the visible band observed by addition of ox2, to an aqueous solution of the dinuclear copper complex. However the selectivity of [Cu2([26]py2N4)(H2O)4]4+ as a receptor for ox2, in the studied series is not sufficiently high to detect ox2, spectrophotometrically in the presence of the other anions. Molecular dynamics simulations indicated that the H4[26]py2N44+ receptor provides a large and flexible cavity to accommodate the studied anions. Molecular recognition is based in electrostatic interactions rather than in multiple hydrogen-bonding interactions acting cooperatively. By contrast, the [Cu2([26]py2N4)]4+ receptor has a well-shaped cavity with adequate size to uptake these anions as bridging ligands with formation of four Cu,O bonds. The ox2, anion is encapsulated within the cascade complex while the remaining anions are located above the N6 macrocyclic plane, suggesting a selective coordination behaviour of this receptor. In spite of our molecular simulation being carried out in gas phase, the modelling results are consistent with the solution studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Minocycline-Based Europium(III) Chelate Complexes: Synthesis, Luminescent Properties, and Labeling to StreptavidinHELVETICA CHIMICA ACTA, Issue 11 2009Takuya Nishioka Abstract Two chelate ligands for europium(III) having minocycline (=(4S,4aS,5aR,12aS)-4,7-bis(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12,12a-tetrahydroxy-1,11-dioxonaphthacene-2-carboxamide; 5) as a VIS-light-absorbing group were synthesized as possible VIS-light-excitable stable Eu3+ complexes for protein labeling. The 9-amino derivative 7 of minocycline was treated with H6TTHA (=triethylenetetraminehexaacetic acid=3,6,9,12-tetrakis(carboxymethyl)-3,6,9,12-tetraazatetradecanedioic acid) or H5DTPA (=diethylenetriaminepentaacetic acid=N,N -bis{2-[bis(carboxymethyl)amino]ethyl}glycine) to link the polycarboxylic acids to minocycline. One of the Eu3+ chelates, [Eu3+(minocycline-TTHA)] (13), is moderately luminescent in H2O by excitation at 395,nm, whereas [Eu3+(minocycline-DTPA)] (9) was not luminescent by excitation at the same wavelength. The luminescence and the excitation spectra of [Eu3+(minocycline-TTHA)] (13) showed that, different from other luminescent EuIII chelate complexes, the emission at 615,nm is caused via direct excitation of the Eu3+ ion, and the chelate ligand is not involved in the excitation of Eu3+. However, the ligand seems to act for the prevention of quenching of the Eu3+ emission by H2O. The fact that the excitation spectrum of [Eu3+(minocycline-TTHA)] is almost identical with the absorption spectrum of Eu3+ aqua ion supports such an excitation mechanism. The high stability of the complexes of [Eu3+(minocycline-DTPA)] (9) and [Eu3+(minocycline-TTHA)] (13) was confirmed by UV-absorption semi-quantitative titrations of H4(minocycline-DTPA) (8) and H5(minocycline-TTHA) (12) with Eu3+. The titrations suggested also that an 1,:,1 ligand Eu3+ complex is formed from 12, whereas an 1,:,2 complex was formed from 8 minocycline-DTPA. The H5(minocycline-TTHA) (12) was successfully conjugated to streptavidin (SA) (Scheme,5), and thus the applicability of the corresponding Eu3+ complex to label a protein was established. [source] Prognostic significance of the therapeutic targets histone deacetylase 1, 2, 6 and acetylated histone H4 in cutaneous T-cell lymphomaHISTOPATHOLOGY, Issue 3 2008L Marquard Aims:, Aberrant histone acetylation has been associated with malignancy and histone deacetylase (HDAC) inhibitors are currently being investigated in numerous clinical trials. So far, the malignancy most sensitive to HDAC inhibitors has been cutaneous T-cell lymphoma (CTCL). The reason for this sensitivity is unclear and studies on HDAC expression and histone acetylation in CTCL are lacking. The aim of this study was to address this issue. Methods and results:, The immunohistochemical expression of HDAC1, HDAC2, HDAC6, and acetylated H4 was examined in 73 CTCLs and the results related to histological subtypes and overall survival. HDAC1 was most abundantly expressed (P < 0.0001), followed by HDAC2; HDAC6 and H4 acetylation were equally expressed. HDAC2 (P = 0.001) and H4 acetylation (P = 0.03) were significantly more common in aggressive than indolent CTCL subtypes. In contrast, no differences were observed for HDAC1 and HDAC6. In a Cox analysis, elevated HDAC6 was the only parameter showing significant influence on survival (P = 0.04). Conclusions:, High expression of HDAC2 and acetylated H4 is more common in aggressive than indolent CTCL. HDAC6 expression is associated with a favorable outcome independent of the subtype. [source] Relational Uncertainty and Message Production Within Courtship: Features of Date Request MessagesHUMAN COMMUNICATION RESEARCH, Issue 3 2006Leanne K. Knobloch This paper theorizes about how relational uncertainty may predict features of date request messages within courtship. It reports a study in which 248 individuals role-played leaving a date request voice mail message for their partner. Relational uncertainty was negatively associated with the fluency (H1), affiliativeness (H2), relationship focus (H3), explicitness (H4), and perceived effectiveness (H5) of messages. Also as expected, relational uncertainty was negatively associated with people's perceptions of the effectiveness of their messages after covarying the judgments of independent observers (H6). Relational uncertainty continued to predict features of messages when length of romantic interest was covaried (RQ1). The paper concludes by discussing the implications of the results for understanding the link between relational uncertainty and message production. [source] High-frequency haplotypes in the X chromosome locus TLR8 are associated with both CD and UC in femalesINFLAMMATORY BOWEL DISEASES, Issue 3 2009Masayuki Saruta MD Abstract Background: TNF-, and IL-1 have been associated with mucosal inflammation in both Crohn's disease (CD) and ulcerative colitis (UC). Innate immune defects have been associated with CD, specifically CARD15/NOD2. Recently, Toll-like receptor 8 (TLR8) signaling has been shown to enhance generation of both cytokines. Interestingly, TLR8 is located on the X chromosome and inflammatory bowel disease (IBD) has been associated with abnormalities of the X chromosome. The aim was to test whether TLR8 haplotypes are associated with IBD. Methods: Subjects (735 CD, 343 UC, 245 controls) were genotyped. Single nucleotide polymorphisms (SNPs) were chosen to tag common Caucasian haplotypes. Results: Both "risk (H4)" and "protective (H1)" TLR8 haplotypes were observed associated with CD in females. Eighteen percent of CD females had H4 compared with 9% of controls (P = 0.02). Fifty-nine percent of CD females had H1 compared with 72% of controls (P = 0.01). H1 was also negatively associated with UC in females (59% of UC, 72% of controls P = 0.03). Diplotype analysis of CD, UC, and all IBD in females revealed that 2 protective haplotypes (H1/H1) had a markedly diminished odds ratio, 0.4,0.5. The presence of a risk haplotype (H4 / not H1) had a significantly increased odds ratio, 2.0,2.2. Thus, the risk for IBD was 4,5 times higher in females with 1 risk haplotype than with the protective/protective diplotype. Conclusions: TLR8 is an X-linked IBD susceptibility gene with both common predisposing and protecting haplotypes. These associations further emphasize the importance of genetic variation in innate immunity as determinants, not only of CD, but of UC as well. (Inflamm Bowel Dis 2008) [source] N-terminal tail of a viral histone H4 encoded in Cotesia plutellae bracovirus is essential to suppress gene expression of host histone H4INSECT MOLECULAR BIOLOGY, Issue 1 2009W. Gad Abstract An endoparasitoid wasp, Cotesia plutellae, possesses a symbiotic bracovirus (CpBV), which facilitates parasitism of a specific host, such as larvae of the diamondback moth, Plutella xylostella. A viral histone H4 (CpBV-H4) has been found in the CpBV genome and its gene product plays a role in impairing the host insect cellular immune response. Based on its high similarity to histone H4 of P. xylostella apart from its extended N-terminal tail, it has been suspected to alter host gene expression. Histone subunits were purified from parasitized P. xylostella larvae and found to contain both host and viral H4s, confirming a previous report of a possible epigenetic mode of action. Moreover, this study showed that the host H4 levels in the parasitized larvae clearly decreased during the parasitization period, whereas CpBV-H4 levels maintained a significant level without significant changes. To understand the decrease of host H4 levels, transcription levels of host H4 were monitored by quantitative reverse-transcriptase PCR (RT-PCR) and showed a significant decrease in parasitized P. xylostella larvae, whereas no significant change of the mRNA level was detected in nonparasitized larvae. This transcriptional control of host H4 expression was also observed by inducing transient expression of CpBV-H4 in nonparasitized P. xylostella. Moreover, co-injection of CpBV-H4 and its specific double-stranded RNA recovered the host H4 expression level. To identify a functional domain of CpBV-H4 involved in the transcriptional control, the extended N-terminal tail of CpBV-H4 was removed by preparing a truncated viral H4 construct in an expression vector by deleting the N-terminal tail of 38 amino acid residues and inducing its expression in nonparasitized P. xylostella larvae. The truncated CpBV-H4 clearly lost its inhibitory effects on host H4 transcription. Moreover, the presence of CpBV-H4 affects the spreading of host haemocytes by an epigenetic effect, which is at least partly restored in larvae expressing the truncated version of CpBV-H4. This study suggests that the viral H4 encoded in CpBV can alter host gene expression with its extended N-terminal tail. [source] Internal Validation of the AmpFlSTR YfilerÔ Amplification Kit for Use in Forensic CaseworkJOURNAL OF FORENSIC SCIENCES, Issue 1 2008Ann Marie Gross M.S. Abstract:, Y-chromosomal short-tandem repeat (Y-STR) amplification has been used in forensic casework at the Bureau of Criminal Apprehension (BCA) Forensic Science Laboratory since 2003. At that time, two separate amplifications were required to type the SWGDAM recommended loci (DYS19, DYS385a/b, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS438, and DYS439). The YfilerÔ kit coamplifies these loci as well as DYS437, DYS448, DYS456, DYS458, DYS635, and Y GATA H4. The YfilerÔ kit was validated following the internal validations outlined in the SWGDAM revised validation guidelines. Our studies show that 0.125 ng of male DNA will generate a complete 17 locus profile and that as little as 0.06 ng of male DNA yields an average of nine loci. In the male,male mixtures, a complete profile from the minor component was detected up to 1:5 ratio; most of the alleles of the minor component were detected at a 1:10 ratio and more than half the alleles of the minor component were detected at a 1:20 ratio. Complete YSTR profiles were obtained when 500 pg male DNA was mixed with female DNA at ratios up to 1:1000. At ratios of 1:5000 and 1:10,000 (male DNA to female DNA) inhibition of the YSTR amplification was evident. The YSTR results obtained for the adjudicated case samples gave significantly more probative information than the autosomal results. Our studies demonstrate that the YfilerÔ kit is extremely sensitive, does not exhibit cross-reactivity with female DNA, successfully types male DNA in the presence of overwhelming amounts of female DNA and is successful in typing actual forensic samples from adjudicated cases. [source] Effect of hydrophobic side-chains on the solvation of imidazolium saltsJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2005Allan D. Headley Abstract The chemical shifts of the aromatic hydrogens of 12 symmetrical imidazolium salts were determined in different deuterated solvents. Based on the magnitude of the chemical shift change for the hydrogens of the imidazolium ion in the various solvents, relationships were developed to determine the relative solute/solvent interactions for these compounds. Owing to different degrees of interactions involving the aromatic hydrogens of the imidazolium cations and anions, there is a variation in the interaction of the hydrogens with the solvent molecules. The intimate interaction that exists between the hydrogens of the imidazolium cation and the BF anion results in the BF salts being less solvated compared with salts containing BF and SbF anions. For imidazolium salts that contain C2H5, C4H9 and C8H17 side-chains bonded in the 1 and 3 positions, the interaction between H2 and the solvents was observed to be greater than for imidazolium salts with C16H33 substituents. On the other hand, for imidazolium salts that have C16H33 substituents the interaction between H2 and the solvents is similar to that for H4 and H5. Copyright © 2005 John Wiley & Sons, Ltd. [source] Electrophoretic Karyotype of the Obligate Biotrophic Parasite Plasmodiophora brassicae Wor.JOURNAL OF PHYTOPATHOLOGY, Issue 6 2001H. Graf Classical genetic analysis is not possible with the protist Plasmodiophora brassicae due to the intracellular life of this obligate biotrophic parasite. An electrophoretic karyotype has been obtained using contour-clamped homogeneous electric field gel electrophoresis to facilitate gene mapping of P. brassicae. Using two different separation conditions 16 chromosomal bands of P. brassicae were distinguished ranging in approximate size from 2.2 Mb to 680 kb. According to this determination of chromosome number and size, the total genome size of P. brassicae was estimated to be 20.3 Mb. The chromosomal bands were further designated by their hybridization pattern with repetitive elements of P. brassicae. The repetitive element H4 (1800 bp) hybridized with 14 chromosomal bands, but the sequence of H4 showed no homology to known centromere or telomere structures and revealed no repetitive motifs. [source] Characterization of the complex formation of 1,6-anhydro-,-maltotriose with potassium using 1H and 39K NMR spectroscopyMAGNETIC RESONANCE IN CHEMISTRY, Issue 11 2009Takayuki Kato Abstract The 1H and 39K longitudinal relaxation times (T1) and 1H diffusion coefficients were measured to investigate the complex formation of 1,6-anhydro-,-maltotriose and potassium ions. Although the 1H- T1 values of H3,, H5,, H1, and H4, decreased in the presence of potassium ions, 1H chemical shifts and 1H diffusion coefficients did not show significant changes. The long-range coupling constants of 3JC,H around the glycosyl bonds did not show significant changes either. In the measurements of 39K spectra, the 39K signal obviously broadened and the 39K- T1 values decreased in the presence of 1,6-anhydro-,-maltotriose, indicating the complex formation of 1,6-anhydro-,-maltotriose and potassium ions. These results indicate that the conformation and molecular volume were unaffected in the complex formation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Chromatin changes on the GSTP1 promoter associated with its inactivation in prostate cancerMOLECULAR CARCINOGENESIS, Issue 10 2007Steven T. Okino Abstract Glutathione- S -transferases (GSTs) are metabolic enzymes that help detoxify and eliminate harmful chemicals. In prostate tumors, expression of GST , (encoded by GSTP1) is frequently lost because of promoter hypermethylation. Here we analyze the native GSTP1 promoter in cancerous and noncancerous human prostate cells to identify structural features associated with its cancer-related transcriptional silencing. We find that in noncancerous prostate cells (RWPE-1 and PWR-1E) GSTP1 is constitutively expressed, not methylated, highly accessible, bound by transcription factors and associated with histones with activating modifications (histone H3 methylated at lysine 4 and acetylated histones H3 and H4). In contrast, in cancerous prostate cells (LNCaP) GSTP1 is not expressed, extensively methylated, inaccessible, lacks bound transcription factors and is not associated with histones with activating modifications. We do not detect significant levels of histones with repressive modifications (histone H3 methylated at lysine 9 or 27) on GSTP1 in any cell line indicating that they are not associated with cancer-related GSTP1 silencing. Treatment of LNCaP cells with 5-azacytidine restores activating histone modifications on GSTP1 and reactivates transcription. We conclude that, in the process of prostate carcinogenesis, activating histone modifications on GSTP1 are lost and the DNA becomes methylated and inaccessible resulting in transcriptional silencing. © 2007 Wiley-Liss, Inc. [source] Maternal chromatin remodeling during maturation and after fertilization in mouse oocytesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2004Marcella Spinaci Abstract Immunofluorescence staining with antibodies against acetylated histone H4 and 5-methylcytosine was carried out to investigate female chromatin remodeling throughout oocyte maturation and chromatin rearrangement involving both male and female genomes after fertilization. Oocyte cytoplasm remodels female chromatin in preparation of the fertilizing event and the subsequent chromatin rearrangement. Histone H4 are in fact progressively deacetylated whereas demethylating enzymes do not seem to be active over this period. The acetylase/deacetylase balance seems to be cell cycle dependent as female chromatin is deacetylated during maturation and reacetylated at telophase II stage both after fertilization and activation. On the contrary, DNA demethylation seems to be strictly selective. It is in fact confined to the remodeling of paternal genome after fertilization of mature oocytes as the ooplasm is not effective in demethylating either paternal chromatin in germinal vesicle breakdown (GVBD) fertilized oocytes or maternal genome of partenogenetically activated oocytes. Surprisingly, we induced maternal chromatin demethylation after fertilization by treating oocytes with a combination of a methyltransferase inhibitor, 5-azacytidine (5-AzaC), and a reversible and specific inhibitor of histone deacetylase, trichostatin A (TSA). This treatment likely induces a hyperacetylation of histones (thus favoring the access to demethylating enzymes by opening female chromatin structure) associated with a block of reparative methylation by inhibiting methytransferases. This manipulation of chromatin remodeling may have applications regarding the biological significance of aberrant DNA methylation. Mol. Reprod. Dev. 69: 215,221, 2004. © 2004 Wiley-Liss, Inc. [source] Dynamical modelling of luminous and dark matter in 17 Coma early-type galaxiesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2007J. Thomas ABSTRACT Dynamical models for 17 early-type galaxies in the Coma cluster are presented. The galaxy sample consists of flattened, rotating as well as non-rotating early-types including cD and S0 galaxies with luminosities between MB=,18.79 and ,22.56. Kinematical long-slit observations cover at least the major-axis and minor-axis and extend to 1,4reff. Axisymmetric Schwarzschild models are used to derive stellar mass-to-light ratios and dark halo parameters. In every galaxy, the best fit with dark matter matches the data better than the best fit without. The statistical significance is over 95 per cent for eight galaxies, around 90 per cent for five galaxies and for four galaxies it is not significant. For the highly significant cases, systematic deviations between models without dark matter and the observed kinematics are clearly seen; for the remaining galaxies, differences are more statistical in nature. Best-fitting models contain 10,50 per cent dark matter inside the half-light radius. The central dark matter density is at least one order of magnitude lower than the luminous mass density, independent of the assumed dark matter density profile. The central phase-space density of dark matter is often orders of magnitude lower than that in the luminous component, especially when the halo core radius is large. The orbital system of the stars along the major-axis is slightly dominated by radial motions. Some galaxies show tangential anisotropy along the minor-axis, which is correlated with the minor-axis Gauss,Hermite coefficient H4. Changing the balance between data-fit and regularization constraints does not change the reconstructed mass structure significantly: model anisotropies tend to strengthen if the weight on regularization is reduced, but the general property of a galaxy to be radially or tangentially anisotropic does not change. This paper is aimed to set the basis for a subsequent detailed analysis of luminous and dark matter scaling relations, orbital dynamics and stellar populations. [source] Axisymmetric orbit models of N -body merger remnants: a dependency of reconstructed mass on viewing angleMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007J. Thomas ABSTRACT We model mock observations of collisionless N -body disc,disc mergers with the same axisymmetric orbit superposition program that has been used to model elliptical galaxies in Coma. The remnants sample representatively the shape distribution of disc,disc mergers, including the most extreme cases, like highly prolate, maximally triaxial and dominantly oblate objects. The aim of our study is to better understand how the assumption of axial symmetry affects reconstructed masses and stellar motions of systems which are intrinsically not axisymmetric, whether the axisymmetry assumption then leads to a bias and how such a potential bias can be recognized in models of real galaxies. The mass recovery at the half-light radius depends on viewing angle and intrinsic shape: edge-on views allow to reconstruct total masses with an accuracy between 20 per cent (triaxial/prolate remnants) and 3 per cent (oblate remnant). Masses of highly flattened, face-on systems are underestimated by up to 50 per cent. Deviations in local mass densities can be larger where remnants are strongly triaxial or prolate. Luminous mass-to-light ratios are sensitive to box orbits in the remnants. Box orbits cause the central value of the Gauss,Hermite parameter H4 to vary with viewing angle. Reconstructed luminous mass-to-light ratios, as well as reconstructed central masses, follow this variation. Luminous mass-to-light ratios are always underestimated (up to a factor of 2.5). Respective dark haloes in the models can be overestimated by about the same amount, depending again on viewing angle. Reconstructed velocity anisotropies , depend on viewing angle as well as on the orbital composition of the remnant and are mostly accurate to about ,,= 0.2. Larger deviations can occur towards the centre or the outer regions, respectively. We construct N -body realizations of the Schwarzschild models to discuss chaotic orbits and the virial equilibrium in our models. In this study we explore the extreme limits of axisymmetric models. Apparently flattened, rotating ellipticals of intermediate mass are likely close to both, axial symmetry and edge-on orientation. Our results imply that Schwarzschild models allow a reconstruction of their masses and stellar anisotropies with high accuracy. [source] Extraction and characterisation of hemicelluloses from maize stemPHYTOCHEMICAL ANALYSIS, Issue 5 2010Xiao-Feng Sun Abstract Introduction , Extraction and characterisation of hemicelluloses are very important for converting them into functional materials and chemicals. Objective , To develop a method for isolation of hemicelluloses from all cell walls. Methodology , Sequential steps using 90% dioxane, 80% acidic dioxane, 100% dimethyl sulphoxide and 8% NaOH were used for extraction of the hemicellulosic preparations (H1, H2, H3 and H4) from maize stem. Advanced NMR techniques were used for the analysis of native hemicelluloses. Results , Hemicelluloses with high yieldd were isolated from all cell walls, and contained arabinoxylan as the major polysaccharide. H3 was substituted by , - l -arabinofuranose, , - d -xylopyranose, and acetyl groups (degree of saturation = 0.12/0.09) at O -3/O -2 of xylan. H4 had a long continuous side chain of arabinose residues, and associated closely with non-cellulosic glucose. The hemicelluloses formed more linkages with guaiacyl lignins, and some p -coumaric acids built a bridge between hemicelluloses and lignin in maize stem. Conclusion , This modified method is successful for the isolation of hemicelluloses with high yields from all cell walls of maize stem. Copyright © 2010 John Wiley & Sons, Ltd. [source] Detergent addition to tryptic digests and ion mobility separation prior to MS/MS improves peptide yield and protein identification for in situ proteomic investigation of frozen and formalin-fixed paraffin-embedded adenocarcinoma tissue sectionsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 10 2009Marie-Claude Djidja Abstract The identification of proteins involved in tumour progression or which permit enhanced or novel therapeutic targeting is essential for cancer research. Direct MALDI analysis of tissue sections is rapidly demonstrating its potential for protein imaging and profiling in the investigation of a range of disease states including cancer. MALDI-mass spectrometry imaging (MALDI-MSI) has been used here for direct visualisation and in situ characterisation of proteins in breast tumour tissue section samples. Frozen MCF7 breast tumour xenograft and human formalin-fixed paraffin-embedded breast cancer tissue sections were used. An improved protocol for on-tissue trypsin digestion is described incorporating the use of a detergent, which increases the yield of tryptic peptides for both fresh frozen and formalin-fixed paraffin-embedded tumour tissue sections. A novel approach combining MALDI-MSI and ion mobility separation MALDI-tandem mass spectrometry imaging for improving the detection of low-abundance proteins that are difficult to detect by direct MALDI-MSI analysis is described. In situ protein identification was carried out directly from the tissue section by MALDI-MSI. Numerous protein signals were detected and some proteins including histone H3, H4 and Grp75 that were abundant in the tumour region were identified. [source] Proteomic profiling of tumor cells after induction of telomere dysfunctionPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2009Stefan Zimmermann Dr. Abstract Cell division in the absence of telomerase causes progressive telomere shortening which ultimately leads to telomere dysfunction and initiation of genome instability. In order to identify factors related to loss of telomere function, the effects of telomerase inhibition on the proteome of five tumor cell lines were followed by SELDI-TOF-MS. Five differentially expressed protein peaks (p<0.01) were found in a total of 60 clones of five cell lines representing four tissues (lung, breast, prostate, and colon) in which telomerase was inhibited by retroviral overexpression of a dominant negative (DN) mutant of human telomerase reverse transcriptase (hTERT). Among these, a 11.3,kDa peak diminished in DN-hTERT clones was identified as histone H4 by nanoflow-HPLC-MS/MS. Immunoblot analysis not only confirmed the decline of histone H4, but also of other core histone proteins including histone H3. Furthermore, upregulation of several cytokeratins was found to be associated with telomere attrition. In conclusion, loss of telomere function is associated with alterations in the proteome which may represent novel biomarkers for the detection of replicative senescence. [source] How Epigenomics Contributes to the Understanding of Gene Regulation in Toxoplasma gondii,THE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 6 2008MATHIEU GISSOT ABSTRACT. How apicomplexan parasites regulate their gene expression is poorly understood. The complex life cycle of these parasites implies tight control of gene expression to orchestrate the appropriate expression pattern at the right moment. Recently, several studies have demonstrated the role of epigenetic mechanisms for control of coordinated expression of genes. In this review, we discuss the contribution of epigenomics to the understanding of gene regulation in Toxoplasma gondii. Studying the distribution of modified histones on the genome links chromatin modifications to gene expression or gene repression. In particular, coincident trimethylated lysine 4 on histone H3 (H3K4me3), acetylated lysine 9 on histone H3 (H3K9ac), and acetylated histone H4 (H4ac) mark promoters of actively transcribed genes. However, the presence of these modified histones at some non-expressed genes and other histone modifications at only a subset of active promoters implies the presence of other layers of regulation of chromatin structure in T. gondii. Epigenomics analysis provides a powerful tool to characterize the activation state of genomic loci of T. gondii and possibly of other Apicomplexa including Plasmodium or Cryptosporidium. Further, integration of epigenetic data with expression data and other genome-wide datasets facilitates refinement of genome annotation based upon experimental data. [source] Genetic diversity of Y-specific STRs in chimpanzees (Pan troglodytes)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2002L. Gusmão Abstract Using the primers described for humans, sequences for 11 Y-specific microsatellites (DYS434, DYS435, DYS436, DYS437, DYS438, DYS439, GATA A10, A7.1, A7.2, C4, and H4 [Gusmão et al., in press]), previously described in 10 male chimpanzees (Pan troglodytes), were confirmed in nine additional male chimpanzees. Sequences for nine additional microsatellites (DYS19, DYS385I and II, DYS389I and II, DYS390, DYS391, DYS392, and DYS393) were determined in all 19 male chimpanzees; homology to human Y-Short Tandem Repeat (STRs) was confirmed by sequencing. Good amplification results were not obtained for DYS19 and DYS385I/II. Two amplicons were obtained for DYS389I/II, but in contrast to humans, the larger fragment was not Y-specific. Moreover, no polymorphism was observed for DYS434, DYS435, or GATA A10. Consequently, these eight STRs were eliminated from further analyses, and haplotype and allele frequencies were estimated for the remaining 12 STRs. A high haplotype diversity value was found (1.000 ± 0.017), demonstrating the usefulness and informative power of these Y-STRs for future studies on chimpanzee population genetics.Am. J. Primatol. 57:21,29, 2002. © 2002 Wiley-Liss, Inc. [source] In vitro specificities of Arabidopsis co-activator histone acetyltransferases: implications for histone hyperacetylation in gene activationTHE PLANT JOURNAL, Issue 4 2007Keith W. Earley Summary In genetic hybrids displaying nucleolar dominance, acetylation of lysines 5, 8, 12 and 16 of histone H4 (H4K5, H4K8, H4K12, H4K16) and acetylation of histone H3 on lysines 9 and 14 (H3K9, H3K14) occurs at the promoters of active ribosomal RNA (rRNA) genes, whereas silenced rRNA genes are deacetylated. Likewise, histone hyperacetylation correlates with the active state of transgenes and of endogenous plant genes involved in physiological processes, including cold tolerance, light-responsiveness and flowering. To investigate histone hyperacetylation dynamics we used sodium butyrate, a histone deacetylase inhibitor known to switch silent rRNA genes on, in order to enrich the pool of acetylated histones. Mass spectrometric analyses revealed unique mono- (K16Ac), di- (K12Ac, K16Ac), tri- (K8Ac, K12Ac, K16Ac), and tetra-acetylated (K5Ac, K8Ac, K12Ac, K16Ac) histone H4 isoforms, suggesting that H4 hyperacetylation occurs in a processive fashion, beginning with lysine 16 and ending with lysine 5. Using a combination of molecular and mass spectrometric assays we then determined the specificities of seven of the nine functional co-activator type histone acetyltransferases (HATs) in Arabidopsis thaliana: specifically HATs of the CBP (HAC1, HAC5, HAC12), GNAT (HAG1, HAG2), and MYST families (HAM1, HAM2). Specific HATs acetylate histone H4K5 (HAM1, HAM2), H4K12 (HAG2), and H3K14 (HAG1), suggesting that acetylation of these lysines may have special regulatory significance. Other acetylation events, including histone H3K9 acetylation, are likely to result from the activities of the broad-specificity HAC1, HAC5, and HAC12 histone acetyltransferases. [source] AtMBD9: a protein with a methyl-CpG-binding domain regulates flowering time and shoot branching in ArabidopsisTHE PLANT JOURNAL, Issue 2 2006Mingsheng Peng Summary The functional characterization of mammalian proteins containing a methyl-CpG-binding domain (MBD) has revealed that MBD proteins can decipher the epigenetic information encoded by DNA methylation, and integrate DNA methylation, modification of chromatin structure and repression of gene expression. The Arabidopsis genome has 13 putative genes encoding MBD proteins, and no specific biological function has been defined for any AtMBD genes. In this study, we identified three T-DNA insertion mutant alleles at the AtMBD9 locus, and found that all of them exhibited obvious developmental abnormalities. First, the atmbd9 mutants flowered significantly earlier than wild-type plants. The expression of FLOWERING LOCUS C (FLC), a major repressor of Arabidopsis flowering, was markedly attenuated by the AtMBD9 mutations. This FLC transcription reduction was associated with a significant decrease in the acetylation level in histone H3 and H4 of FLC chromatin in the atmbd9 mutants. Secondly, the atmbd9 mutants produced more shoot branches by increasing the outgrowth of axillary buds when compared with wild-type plants. The two known major factors controlling the outgrowth of axillary buds in Arabidopsis, auxin and the more axillary growth (MAX) pathway, were found not to be involved in producing this enhanced shoot branching phenotype in atmbd9 mutants, indicating that AtMBD9 may regulate a novel pathway to control shoot branching. This pathway is not related to FLC expression as over-expression of FLC in atmbd9-2 restored its flowering time to one similar to that of the wild type, but did not alter the shoot branching phenotype. [source] Microarray analysis of chromatin-immunoprecipitated DNA identifies specific regions of tobacco genes associated with acetylated histonesTHE PLANT JOURNAL, Issue 6 2004Yii Leng Chua Summary The acetylation states of histones present on the upstream, promoter, coding or intronic regions of 88 tobacco genes were examined with chromatin immunoprecipitation (ChIP) experiments using antibodies that recognised acetylated histone H4. The DNA sequences enriched in the immunoprecipitates were amplified by ligation-mediated PCR, labelled with Cy-dUTP and hybridised to DNA microarrays. In green tobacco shoots, histone H4 acetylation was localised to 300,600-bp sequences in the promoters or coding regions of 31 genes, or occurred extensively over several kilobase-pair regions containing the upstream, promoter and/or coding regions of 25 genes. Genes associated with high histone H4 acetylation levels at promoters were actively expressed, whereas genes depleted in acetylated histone H4 were non-transcribed or expressed at very low levels, suggesting a correlation between histone H4 acetylation and gene activity. Trichostatin A (TA), an inhibitor of histone deacetylases (HDAs), did not alter histone H4 acetylation states globally but increased acetylation levels at specific tobacco sequences, suggesting that HDAs are targeted to particular nucleosomes. Genes that were upregulated by TA were associated with increased histone H4 acetylation at promoter or coding regions, indicating that acetylation of histones on coding regions may activate transcription. Increased histone H4 acetylation leading to elevated expression was observed on genes with diverse functions, suggesting that histone H4 acetylation is involved in regulation of many plant processes. [source] Molecular characterization of CTX-M-15-producing clinical isolates of Escherichia coli reveals the spread of multidrug-resistant ST131 (O25:H4) and ST964 (O102:H6) strains in NorwayAPMIS, Issue 7 2009UMAER NASEER Nationwide, CTX-M-producing clinical Escherichia coli isolates from the Norwegian ESBL study in 2003 (n=45) were characterized on strain and plasmid levels. BlaCTX-M allele typing, characterization of the genetic environment, phylogenetic groups, pulsed field gel electrophoresis (PFGE), serotyping and multilocus sequence typing were performed. Plasmid analysis included S1 -nuclease-PFGE, polymerase chain reaction-based replicon typing, plasmid transfer and multidrug resistance profiling. BlaCTX-M-15 (n=23; 51%) and blaCTX-M-14 (n=11; 24%) were the major alleles of which 18 (78%) and 6 (55%), respectively, were linked to ISEcp1. Thirty-two isolates were of phylogenetic groups B2 and D. Isolates were of 29 different XbaI-PFGE-types including six regional clusters. Twenty-three different O:H serotypes were found, dominated by O25:H4 (n=9, 20%) and O102:H6 (n=9, 20%). Nineteen different STs were identified, where ST131 (n=9, 20%) and ST964 (n=7, 16%) were dominant. BlaCTX-M was found on ,100 kb plasmids (39/45) of 10 different replicons dominated by IncFII (n=39, 87%), FIB (n=20, 44%) and FIA (n=19, 42%). Thirty-nine isolates (87%) displayed co-resistance to other classes of antibiotics. A transferable CTX-M phenotype was observed in 9/14 isolates. This study reveals that the majority of CTX-M-15-expressing strains in Norway are part of the global spread of multidrug-resistant ST131 and ST-complex 405, associated with ISEcp1 on transferrable IncFII plasmids. [source] No effect of extremely low-frequency magnetic field observed on cell growth or initial response of cell proliferation in human cancer cell linesBIOELECTROMAGNETICS, Issue 5 2002Hiroaki Yoshizawa Abstract An effect on the tumor promotion process, as represented by accelerated cell growth, has been indicated as one example of areas that demonstrate the possibility of biological effects of extremely-low frequency magnetic fields. We, therefore, exposed the five cell lines (HL-60, K-562, MCF-7, A-375, and H4) derived from human tumors to a magnetic field for 3 days to investigate the effects on cell growth. Prior to exposure or sham exposure, the cells were precultured for 2 days in low serum conditions. The number of growing cells was counted in a blind manner. To investigate the effect on the initial response of cell proliferation, two cell lines were synchronized in G1 phase by serum starvation and then exposed to a magnetic field for 18 h (H4 cells) or 24 h (MCF-7 cells), both with and without serum stimulation. The rate of DNA synthesis, taken as a measure of the cell proliferation, was determined by following the incorporation of [3H]-thymidine into the DNA. Three different magnetic field polarizations at both 50 and 60 Hz were used: linearly polarized (vertical); circularly polarized; and an elliptically polarized field. Magnetic field flux densities were set at 500, 100, 20 and 2 ,T (rms) for the vertical field and at 500 ,T (rms) for the rotating fields. No effect of magnetic field exposure was observed on either cell growth or the initial response of cell proliferation. Bioelectromagnetics 23:355,368, 2002. © 2002 Wiley-Liss, Inc. [source] | |||||||||||||||||||