Search results for "complex"
showing 10 items of 5889 documents
Structural characterisation of the natural membrane-bound state of melittin: a fluorescence study of a dansylated analogue
1997
Abstract The binding of a dansylated analogue of melittin (DNC–melittin) to natural membranes is described. The cytolytic peptide from honey bee venom melittin was enzymatically labelled in its glutamine-25 with the fluorescent probe monodansylcadaverine using guinea pig liver transglutaminase. The labelled peptide was characterised functionally in cytolytic assays, and spectroscopically by circular dichroism and fluorescence. The behaviour of DNC–melittin was, in all respects, indistinguishable from that of the naturally occurring peptide. We used resonance energy transfer to measure the state of aggregation of melittin on the membrane plane in synthetic and natural lipid bilayers. When bo…
Metal NHC Complexes with Naphthalimide Ligands as DNA-Interacting Antiproliferative Agents
2017
Naphthalimide-based N-heterocyclic carbene (NHC) complexes of the type [(1,5-cyclooctadiene)(NHC)RhCl)] (4 a-c), [(p-cymene)(NHC)RuCl2 )] (5 a-c), and [(NHC)CuBr] (6 a-c) were synthesized and investigated as antiproliferative agents that target DNA. The cytotoxic effects were largely driven by the naphthalimide structure, which is a DNA-intercalating moiety. Regarding the metal center, the highest activities were observed with the rhodium complexes, and cytotoxic activity was significantly lower for the ruthenium derivatives. The stable coordination of the NHC ligands of selected complexes 4 b and 5 b in solution was confirmed, and their DNA binding properties were studied by UV/Vis spectro…
Nickel(II), copper(II) and zinc(II) metallo-intercalators: structural details of the DNA-binding by a combined experimental and computational investi…
2014
We present a thorough characterization of the interaction of novel nickel(II) (1), copper(II) (2) and zinc(II) (3) Schiff base complexes with native calf thymus DNA (ct-DNA), in buffered aqueous solution at pH 7.5. UV-vis absorption, circular dichroism (CD) and viscometry titrations provided clear evidence of the intercalative mechanism of the three square-planar metal complexes, allowing us to determine the intrinsic DNA-binding constants (K(b)), equal to 1.3 × 10(7), 2.9 × 10(6), and 6.2 × 10(5) M(-1) for 1, 2 and 3, respectively. Preferential affinity, of one order of magnitude, toward AT compared to GC base pair sequences was detected by UV-vis absorption titrations of 1 with [poly(dG-d…
Comprehending city and its production in Africa through a systemic approach : example of the city of Diamniadio, Dakar
2022
For a long time, the analysis of the production of the city in Africa was based on an exogenous perception according to urban models theorized and experimented with in the Occidental countries, then diffused and applied through different mechanisms in the South, bearing witness to historical relations - through the making of the colonial city - and present relations - in the context of the making of new towns. After independence, researchers looked at the redefinition of the city in Africa with its complexity and plurality according to geographical and historical trajectories, proposing new urban theories that were more nuanced and linked to local and contextual realities. Therefore, follow…
Synthesis, spectroscopic characterization and antiproliferative activity of two platinum(II) complexes containing N-donor heterocycles
2014
Abstract Novel mononuclear complexes of Pt(II), cis -[PtCl 2 (DMSO)HL]·2DMSO ( 1 ), where HL = 7-amino-2-(methylthio)[1,2,4]triazolo[1,5- a ]pyrimidine-6-carboxylic acid and Pt(bdt)Cl 2 ( 2 ), where bdt = [2,4-bis(5,6-diphenyl-1,2,4-triazin-3yl)-pyridine] have been synthesized and characterized by elemental analysis, IR and 1 H NMR spectroscopy and X-ray crystallography diffraction analyses. The molecular structure of ( 1 ) shows that Pt(II) ion has a square planar geometry with N(3) bonded heterocycle ligand, two cis chloride anions and S-bonded dimethylsulfoxide. The antiproliferative activity of complexes ( 1 ) and ( 2 ) has been tested in vitro against HepG2 human hepatoma cells and non…
Possible relationship between micronucleated and binucleated cells induced by cisplatin in cultured CHO cells
1993
Abstract Chinese hamster ovary (CHO) cells were treated with a single dose (10 μg/ml) of cis-diammino-dichloroplatinum (II) (cisplatin) for 1 h and the effect of the drug on the kinetics of proliferation of the cultures was studied. It was found that the drug produces a delay in the proliferation rates of the treated cultures. The induction of micronuclei and binucleated cells (BC) at different times after treatment have also been studied, and the ability of these cells to undergo DNA synthesis (measured as the ability to incorporate [3H]thymidine) is shown. It was found that cisplatin induced a particular type of BC that contains one or more micronuclei rather than a pure population of BC.…
Cytotoxicities of Polysubstituted Chlorodicarbonyl(cyclopentadienyl) and (Indenyl)ruthenium Complexes
2013
Polysubstituted cyclopentadienyl and indenyl complexes of ruthenium were synthesized and investigated to elucidate their potential cytotoxic activities. In particular, substituted (indenyl)ruthenium complexes inhibited the proliferation of a panel of human adherent cancer cells with comparable activity to reference agent cisplatin. One of the active compounds exerted a concentration dependent inhibition of cell cycle at G1–S transiton as evidenced by flow cytometry.
Wastewaters from citrus processing industry as natural biostimulants for soil microbial community
2020
Abstract Citrus fruit processing wastewaters (CWWs), being rich in organic matter, may be a valuable resource for agricultural irrigation and, possibly, for the improvement of soil organic carbon (TOC). This issue is becoming crucial for soils of arid and semiarid environments increasingly experiencing water scarcity and continuous decline of TOC towards levels insufficient to sustain crop production. However, before using CWWs in agriculture their effects on the soil living component have to be clarified. Therefore, in this study we assessed the impact of CWWs on soil chemical and biochemical properties. Under laboratory conditions, lemon, orange and tangerine wastewaters were separately a…
Volatile Compounds of Lemon and Grapefruit IntegroPectin
2020
An HS-SPME GC-MS analysis of the volatile compounds adsorbed at the outer surface of lemon and grapefruit pectins obtained via the hydrodynamic cavitation of industrial waste streams of lemon and grapefruit peels in water suggests important new findings en route to understanding the powerful and broad biological activity of these new pectic materials. In agreement with the ultralow degree of esterification of these pectins, the high amount of highly bioactive &alpha
Pseudocomplements in sum-ordered partial semirings
2007
We study a particular way of introducing pseudocomplementation in ordered semigroups with zero, and characterise the class of those pseudocomplemented semigroups, termed g-semigroups here, that admit a Glivenko type theorem (the pseudocomplements form a Boolean algebra). Some further results are obtained for g-semirings – those sum-ordered partially additive semirings whose multiplicative part is a g-semigroup. In particular, we introduce the notion of a partial Stone semiring and show that several well-known elementary characteristics of Stone algebras have analogues for such semirings.