Search results for "Nucleases"
showing 10 items of 147 documents
Ribonuclease H levels in herpes simplex virus-infected cells.
1980
Two forms of ribonuclease H (RNase H) have been identified both in uninfected and Herpes Simplex virus (HSV-)infected BHK cells. Identical RNase H species were detected in control- as well as in infected cells. RNase H I and II have not been found to be associated both with host cell DNA polymerase alpha and beta and HSV-induced DNA polymerase. Infection of BHK cells with HSV type 1 does not lead to a pronounced alteration of RNase H II activity but to an increase (3-fold) of the extractable RNase H I activity. RNase H I activity increases to a maximum between 8-10 hours p.i.; the bulk of HSV-DNA synthesis occurs between 6-8 hours p.i. From these experiments we draw the preliminary conclusi…
Oxidative nuclease activity of ferromagnetically coupled μ-hydroxo-μ-propionato copper(II) complexes [Cu3(L)2(μ-OH)2(μ-propionato)2] (L=N-(pyrid-2-yl…
2008
Three doubly-bridged, trinuclear copper(II) compounds with hydroxo and carboxylato bridges, ∞ 1 [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] ∞ 1 [ Cu 3 ( L 1 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] (1) , [Cu 3 (L2) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ] (2) and ∞ 1 {[Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 ]} ∞ 1 { [ Cu 3 ( L 3 ) 2 ( μ - OH ) 2 ( μ - propionato ) 2 ] } [Cu 3 (L3) 2 (μ-OH) 2 (μ-propionato) 2 (DMF) 2 ]} (3) [HL1 = N -(pyrid-2-ylmethyl)benzenesulfonylamide, HL2 = N -(pyrid-2-ylmethyl)toluenesulfonylamide, HL3 = N -(pyrid-2-ylmethyl)naphthalenesulfonylamide], have been synthesized and characterized. 1 is built from [Cu 3 (L1) 2 (μ-OH) 2 (μ-propionato) 2 ] clusters. Each unit contai…
DNA interaction of CuII, NiII and ZnII functionalized salphen complexes: studies by linear dichroism, gel electrophoresis and PCR.
2013
The interaction of salphen-type NiII, CuII and ZnII complexes with native DNA was investigated by exploiting linear dichroism experiments. The NiII complex behaves as a typical intercalator, binding strongly and stiffening and unwinding the DNA. The strength of the DNA interaction is slightly weaker for the copper complex and much weaker for the zinc complex. Plasmid-DNA gel electrophoresis experiments indicated that while CuII and ZnII complexes do not induce the unwinding of supercoiled DNA, the NiII complex has a nuclease activity without the addition of external agents. On the other hand, as shown in the PCR assays, we demonstrate that, at the used concentrations, only the CuII complex …
Synthesis, structure, and nuclease properties of several binary and ternary complexes of copper(II) with norfloxacin and 1,10 phenantroline
2007
Three new binary Cu(II) complexes of norfloxacin have been synthesized and characterized. We also report the synthesis, characterization and X-ray crystallographic structures of a new binary compound, [Cu(HNor)(2)]Cl(2).2H(2)O (2) and two new ternary complexes norfloxacin-copper(II)-phen, [Cu(Nor)(phen)(H(2)O)](NO(3)).3H(2)O (4), and [Cu(HNor)(phen)(NO(3))](NO(3)).3H(2)O (5). The structure of 2 consists of two crystallographically independent cationic monomeric units of [Cu(HNor)(2)](2+), chloride anions, and uncoordinated water molecules. The Cu(II) ion is placed at a center of symmetry and is coordinated to two norfloxacin ligands which are related through the inversion center. The struct…
Evolutionary relationships among the members of an ancient class of non-LTR retrotransposons found in the nematode Caenorhabditis elegans.
1998
We took advantage of the massive amount of sequence information generated by the Caenorhabditis elegans genome project to perform a comprehensive analysis of a group of over 100 related sequences that has allowed us to describe two new C. elegans non-LTR retrotransposons. We named them Sam and Frodo. We also determined that several highly divergent subfamilies of both elements exist in C. elegans. It is likely that several master copies have been active at the same time in C. elegans, although only a few copies of both Sam and Frodo have characteristics that are compatible with them being active today. We discuss whether it is more appropriate under these circumstances to define only 2 elem…
Structural basis and effect of copper(II) complexes with 4-oxo-thiazolidine ligands on DNA binding and nuclease activity
2020
Abstract Seven novel Copper(II) complexes, namely [Cu(Am4DHotaz)(H2O)2](ClO4) (1), [Cu(Am4DHotaz)(NO3)(MeOH)]·H2O (2), [Cu(Am4Motaz)2(H2O)](ClO4)2·0.83H2O (3), [Cu(Am4Motaz)2(NO3)]NO3·MeOH (4), [Cu(Am4Eotaz)2(NO3)]3(NO3)3·2H2O (5), [Cu(Am4Eotaz)2(ClO4)](ClO4) (6) and [Cu(Am4Eotaz)(ClO4)(H2O)](ClO4) (6a) (HAm4DHotaz = N′-(4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide, Am4Motaz = N′-(3-methyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide and Am4Eotaz = N′-(3-ethyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide), have been successfully synthesized and characterized by several physicochemical techniques and, for 1–6 complexes, single crystal X-ray diffraction. Ha…
Secretion of neutral and acid DNases in cultivated human lymphocytes after incubation with DNA; possible consequences for inhalation anesthesia.
1995
Abstract After incubation with DNA human lymphocytes release neutral and acid DNase activities into the culture medium; the release depends on DNA concentration and time of cultivation. The electrophoretic mobility of the released neutral DNase activity is in accordance with DNase I and the electrophoretic mobility of the released acid DNase activity with DNase II. The released DNase activities do not originate from dead cells and are not influenced by blast cell formation. The anesthetic halothane can inhibit the released neutral and acid DNase activities. Inhalation anesthesia can possibly disturb the correlation between DNA and DNases in human blood.
Alterations of Activities of Ribonucleases and Polyadenylate Polymerase in Synchronized Mouse L Cells
1977
The activities of the three known catabolic and the one anabolic polyadenylate enzymes have been determined in synchronized L5178y cells: endoribonuclease, exoribonuclease, 5'-nucleotidase and poly(A) polymerase (Mg2+-dependent). These four enzymes were found primarily in the nuclear fraction. The activity of poly(A) polymerase remains essentially constant during the transition from G1 to S phase. However, the poly(A) catabolic enzyme activities increase parallel with DNA synthesis; the endoribonuclease activity increases 4-fold during G1 to S phase, the exoribonuclease and the nucleotidase activities increasing 30-fold and 16-fold. During the S phase the poly(A)-degrading enzymes are far m…
Synthesis and copper-mediated nuclease activity of a tetracationic tris(2,2′-bipyridine) ligand
2009
Abstract We report herein the synthesis of a novel tetracationic tris(2,2′-bipyridine) ligand 4 . We show that this ligand metalated with copper(II), and in the presence of ascorbate as a reducing agent, strongly damages pUC18 plasmid DNA. Copper complex formation was demonstrated by ESI-MS (electrospray ionization-mass spectrum) at a 1:3 ligand to metal ratio. Binding of both 4 and its copper(II) complex to CT-DNA (calf thymus DNA) was characterized by viscosimetry, thermal denaturation and fluorescence-based competition assays. The viscosimetric data indicated that 4 and its copper(II) complex bind DNA through partial intercalation and thermal denaturation studies revealed a significant i…
Heavy metal ion induction of adhesion molecules and cytokines in human endothelial cells: the role of NF-kappaB, I kappaB-alpha and AP-1.
1997
We analyzed the influence of heavy-metal ions on human umbilical vein endothelial cells (HUVEC) in comparison to proinflammatory cytokines (TNF-alpha, IL-1beta) and lipopolysaccharide (LPS). Adhesion molecule and cytokine expressions are upregulated by heavy-metal exposure. Expression of E-selectin on the cell surface was strongly induced by 1-mM concentrations of NiCl2 and CoCl2, whereas ZnCl2 and CrCl3 had no influence. Furthermore, it is shown that NiCl2 induces mRNA expression of E-selectin, intercellular adhesion molecule-1, IL-6 and IL-8 in a 1-mM concentration. The transcription factor NF-kappaB is known to be involved in the regulation of adhesion molecule expression in endothelial …