Search results for "hate"
showing 10 items of 2099 documents
Poly-ADP-Ribose (PAR) as an epigenetic flag
2009
Epigenetics is the study of hereditable chromatin modifications, such as DNA methylation, histone modifications, and nucleosome-remodelling, which occur without alterations to the DNA sequence. The establishment of different epigenetic states in eukaryotes depends on regulatory mechanisms that induce structural changes in chromatin in response to environmental and cellular cues. Two classes of enzymes modulate chromatin accessibility: chromatin-covalent modifiers and ATP-dependent chromatin remodelling complexes. The first class of enzymes catalyzes covalent modifications of DNA as well as the amino- and carboxy-terminal tails of histones, while the second uses the energy of ATP hydrolysis …
The nucleosome-remodeling ATPase ISWI is regulated by poly-ADP-ribosylation.
2008
ATP-dependent nucleosome-remodeling enzymes and covalent modifiers of chromatin set the functional state of chromatin. However, how these enzymatic activities are coordinated in the nucleus is largely unknown. We found that the evolutionary conserved nucleosome-remodeling ATPase ISWI and the poly-ADP-ribose polymerase PARP genetically interact. We present evidence showing that ISWI is target of poly-ADP-ribosylation. Poly-ADP-ribosylation counteracts ISWI function in vitro and in vivo. Our work suggests that ISWI is a physiological target of PARP and that poly-ADP-ribosylation can be a new, important post-translational modification regulating the activity of ATP-dependent nucleosome remodel…
Alteration of poly (ADP-Rib) synthesis during progesterone- caused gene expression in oviducts of quails.
1976
Summary The biological model of the selective induction of RNA synthesis in oviducts of estrogen stimulated immature quails by progesterone has been used to clarify whether poly (ADP-Rib) is involved in DNA transcription. The chromatin-bound as well as the soluble poly (ADP-Rib) polymerase has been isolated from oviducts and the optimal reaction conditions have been determined. The activities, as measured by the incorporation rates of NAD + into poly (ADP-Rib), of both, chromatin-bound « endogenouspolymerase (in the absence of « exogenousDNA and histones) and soluble enzyme (native DNA - lysine-rich histone ratio: 4.3) from progesterone treated quail oviducts, have been determined to be onl…
Investigation of polymer organic deposit formed on nickel phosphate in oxidative dehydrogenation of ethylbenzene
1997
Abstract Several polymer organic deposits (PODS) had been obtained by heating of nickel polyphosphate (NiP) at 720 K for 1, 4, or 10 h in a stream of helium (carrier gas) containing 20% of (ethylbenzene : oxygen= 1: 0.5] mixture. The samples were tested in oxidative dehydrogenation (OD) of ethylbenzene (EB) to styrene, before and after their separation from the inorganic part of NiP as catalysts. Some functional groups or bonds, important for enhancement of styrene yield, have been found in the PODS. The POD obtained after 10-h coking of NiP, containing a mixture of both insoluble fused-ring and soluble-in-pyridine macromolecules, provided with at least two types of catalytically active cen…
Dual removal and selective recovery of phosphate and an organophosphorus pesticide from water by a Zr-based metal-organic framework
2021
The authors express their thanks for the financial support provided by the Marie Sklodowska-Curie Individual Fellowships (H2020-MSCA-IF-2019-EF-ST-888972-PSustMOF, F.J.C.; H2020-MSCA-IF-2016-GF-749359-EnanSET, N.M.P.) within the European Union H2020 programme and EU FEDER. MINECO (CTQ2017-84692-R, PID2020-113608RB-I00, PEJ2018-004022-A), Universidad de Granada (Plan Propio de Investigacion and Programa Operativo FEDER Andalucia 2014-2020: B-FQM-364-UGR18), Junta de Andalucia (P18-RT-612) and 2020 Post-doctoral Junior Leadere-Retaining Fellowship, la Caixa Foundation (ID 100010434 and fellowship code LCF/BQ/PR20/11770014, N.M.P.) are also acknowledged for funding. Funding for open access cha…
Drug release from calcium and zinc pectinate beads: Impact of dissolution medium composition
2011
The aim of this study was to investigate drug release from calcium and zinc pectinate beads and to understand the impact of medium electrolytes during drug transfer. A potential drug carrier for colonic drug delivery (rutin) was prepared with calcium and zinc pectinate beads and was tested in three different simulated intestinal fluids (pH 7.3) with phosphates (Sorensen’s and Mc Ilvaine’s buffers) and without phosphates (Tris-buffer). According to swelling studies and zinc ions release, it was showed that zinc ions keep adhering to the bead surface. Drug release and swelling behaviour from the two dosage forms depend not only on pH and ionic strength but also on the electrolytes there were …
Joining Two Natural Motifs: Catechol-Containing Poly(phosphoester)s.
2017
Numerous catechol-containing polymers, including biodegradable polymers, are currently heavily discussed for modern biomaterials. However, there is no report combining poly(phosphoester)s (PPEs) with catechols. Adhesive PPEs have been prepared via acyclic diene metathesis polymerization. A novel acetal-protected catechol phosphate monomer was homo- and copolymerized with phosphoester comonomers with molecular weights up to 42000 g/mol. Quantitative release of the catechols was achieved by careful hydrolysis of the acetal groups without backbone degradation. Degradation of the PPEs under basic conditions revealed complete and statistical degradation of the phosphotri- to phosphodiesters. In …
Polyphosphate: A Morphogenetically Active Implant Material Serving as Metabolic Fuel for Bone Regeneration
2015
The initial mineralization centers during human bone formation onto osteoblasts are composed of CaCO3 . Those bioseeds are enzymatically formed via carbonic anhydrase(s) in close association with the cell surface of the osteoblasts. Subsequently, the bicarbonate/carbonate anions are exchanged non-enzymatically by inorganic phosphate [Pi ]. One source for the supply of Pi is polyphosphate [polyP] which is a physiological polymer, formed in the osteoblasts as well as in the platelets. The energy-rich acid anhydride bonds within the polyP chain are cleaved by phosphatase(s); during this reaction free-energy might be released that could be re-used, as metabolic fuel, for the maintenance of the …
Amorphous Ca2+ polyphosphate nanoparticles regulate the ATP level in bone-like SaOS-2 cells
2015
ABSTRACT Polyphosphate (polyP) is a physiologically occurring polyanion that is synthesized especially in bone-forming osteoblast cells and blood platelets. We used amorphous polyP nanoparticles, complexed with Ca2+, that have a globular size of ∼100 nm. Because polyP comprises inorganic orthophosphate units that are linked together through high-energy phosphoanhydride bonds, we questioned whether the observed morphogenetic effect, elicited by polyP, is correlated with the energy-generating machinery within the cells. We show that exposure of SaOS-2 osteoblast-like cells to polyP results in a strong accumulation of mitochondria and a parallel translocation of the polyP-degrading enzyme alka…
Inorganic Polyphosphates: Biologically Active Biopolymers for Biomedical Applications
2013
Inorganic polyphosphate (polyP) is a widely occurring but only rarely investigated biopolymer which exists in both prokaryotic and eukaryotic organisms. Only in the last few years, this polymer has been identified to cause morphogenetic activity on cells involved in human bone formation. The calcium complex of polyP was found to display a dual effect on bone-forming osteoblasts and bone-resorbing osteoclasts. Exposure of these cells to polyP (Ca2+ complex) elicits the expression of cytokines that promote the mineralization process by osteoblasts and suppress the differentiation of osteoclast precursor cells to the functionally active mature osteoclasts dissolving bone minerals. The effect o…