Search results for "polycyclic compounds"
showing 10 items of 373 documents
Influence of phytosterols on the structural and dynamic properties of plant plasma membrane
2008
National audience; The complex mixture of sterols, namely phytosterols, found in the plasma membrane (PM) of plant cells is an intriguing characteristic. In the present work, we characterized the sterol composition of tobacco BY-2 cell PM, and we adapted a sterol manipulation method to this plant material. Methyl-b-cyclodextrin was found to induce a drastic reduction of the PM total free sterol content, with a low specificity for the different phytosterols, and without effect on steryl-conjugates. The consequences of phytosterols depletion were investigated by means of fluorescence spectroscopy and biochemical detergent resistant membrane (DRM) fraction purification methods. Data obtained w…
Evaluation of the environmental fate and ecotoxicological impact of the pesticide chlorpyrifos in soil for improvement of its environmental risk asse…
2016
EABIOMEUBINRA; Pesticides protect crops from various pests but can also harm nontarget organisms. To minimize risks for the environment and human health, a huge amount of studies are carried out and evaluated during the authorization process of each pesticide. However, the prediction of the environmental fate and ecotoxicological impact of a pesticide remains difficult. Several 100 formerly used pesticides are now banned because unexpected risks emerged decades after their authorization. Risk assessment documents of the organophosphate insecticide chlorpyrifos (CHL) particularly lack information about its degradation and potential transformation products in soil, and its impact on non-targe…
Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins.
2003
Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio of cyclodextrin to aminophosphonic acid, and on the type of the applied chiral selector. Optimization of process conditions allowed enantiomeric baseline separation or partial separation of 12 out of 14 alpha-aminophosphonic acids studied. This type of CE might therefore be successfully used for routine determination of enantiomeric purity of aminophosphonic acids.
Energy transfer between polyamine chains bearing naphthalene terminal units and k3[Co(CN)6]: An example of a molecular photoreactor
2002
Molecular photoreactors consisting of polyamine chains (receptors) bearing terminal naphthalene units (antennae) are described. The receptors are used to bind the substrate hexacyanocobaltate(III) and the antennae to transfer energy to the complex and thus promote a photoaquation reaction.
Pheromone-binding proteins of scarab beetles.
1998
: We have characterized Pheromone binding proteins (PBPs) present in the antennae of several species of scarab beetles. In most cases there was only one class of PBP, which was expressed in both sexes. Both Anomala osakana and Popillia japonica possess a single PBP, highly homologous to each other. In each species the same PBP seems to recognize both enantiomers of japonilure, which have opposite biological functions, i.e., the sex Pheromone and the behavioral antagonist (stop signal). The purified PBP of A. osakana binds both enantiomers apparently with the same low affinity. Unexpectedly, these ligands were bound by moth PBPs, which utilize Pheromones with unrelated structures. These find…
Organometallic complexes with biological molecules: XIII. Organotin(IV)[meso-tetra (4-carboxyphenyl)porphinate]s and the cell cycle: a flow-cytometri…
1999
The cytotoxic derivatives diorganotin(IV) and triorganotin(IV) [meso-tetra(4-carboxyphenyl)porphinates, with stoichiometries [R2Sn]2TPPC and [R3Sn]4TPPC [R = Me, Bu, Ph; TPPC4−= meso-tetra(4-carboxyphenyl)porphinate4−], namely bis[dimethyltin(IV)], bis[dibutyltin(IV)], bis[diphenyltin(IV)], tetra[trimethyltin(IV)], tetra[tributyltin(IV)] and tetra[triphenyltin(IV)] [meso-tetra(4-carboxyphenyl)porphinate]s, have been used to investigate their effects on the cultured human kidney cell cycle in order to understand further the origin of cell-growth inhibition induced by the above-mentioned chemicals. The cell-cycle-dependent DNA content distribution of cultured cells exposed to these compounds…
Side-Effects of High-Dose Dicloxacillin Therapy
1976
The limiting toxic factor in high-dose penicillin therapy seems to be the effect on the central nervous system. In comparison with other semisynthetic penicillins dicloxacillin is the most neurotoxic in rabbits, as previous studies have shown (11). In rabbits neurotoxic serum levels also produce hemolysis. Cloxacillin, oxacillin and carbenicillin showed to be less neurotoxic and did not induce hemolysis. The present study was undertaken to determine whether in high-dose dicloxacillin therapy hemolysis is likely in man and is, therefore, of clinical importance.
Interaction between 24-hydroxycholesterol, oxidative stress, and amyloid-β in amplifying neuronal damage in Alzheimer’s disease: three partners in cr…
2011
All three cholesterol oxidation products implicated thus far in the pathogenesis of Alzheimer's disease, 7β-hydroxycholesterol, 24-hydroxycholesterol, and 27-hydroxycholesterol, markedly enhance the binding of amyloid-beta (Aβ) to human differentiated neuronal cell lines (SK-N-BE and NT-2) by up-regulating net expression and synthesis of CD36 and β1-integrin receptors. However, only 24-hydroxycholesterol markedly potentiates the pro-apoptotic and pro-necrogenic effects of Aβ(1-42) peptide on these cells: 7β-hydroxycholesterol and 27-hydroxycholesterol, like unoxidized cholesterol, show no potentiating effect. This peculiar behavior of 24-hydroxycholesterol at physiologic concentrations (1 μ…
Refined carotenoid analysis of the major light-harvesting complex of Mantoniella squamata
1997
The major light-harvesting complex (LHC) of the prasinophycean alga Mantoniella squamata is unique compared to other chlorophyll (Chl) a/b-binding LHC with respect to the primary protein structure and the pigmentation. Although the presence of Chl a, Chl b, a Chl c-type pigment and the xanthophylls neoxanthin, violaxanthin and prasinoxanthin was clearly determined, several carotenoids remained unidentified or were described controversially. We re-analysed the carotenoid composition and identified a new set of xanthophylls present in the LHC: uriolide, micromonol, micromonal and dihydrolutein. Additionally, one hydrophobic component was detected, presumably a xanthophyll. The pigment analysi…
Environmental analysis of chlorinated aromatic thioethers, sulphoxides and sulphones
1993
Abstract Chlorinated aromatic thioethers discussed here are polychlorinated dibenzothiophenes, thianthrenes and diphenylsulphides. Relatively little is known about their occurrence, behaviour and fate in the environment. Polychlorinated dibenzothiophenes and diphenylsulphides have recently been found to be formed in waste combustion and analysed in pulp mill effluents. Chlorinated sulphoxides and sulphones are usually metabolites or oxidation products of different chlorinated aromatic compounds. Different gas chromatographic-mass spectrometric techniques are used in the analysis of the chlorinated thioethers. The sulphoxides and sulphones, because of their higher polarity, can be isolated f…