Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Perturbations induced by alpha- and beta-endosulfan in lipid membranes: a DSC and fluorescence polarization study
Autore:
Videira, RA; Antunes-Madeira, MC; Madeira, VMC;
Indirizzi:
Ctr Neurociencias, Dept Zool, P-3000 Coimbra, Portugal Ctr Neurociencias Coimbra Portugal P-3000 Zool, P-3000 Coimbra, Portugal
Titolo Testata:
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES
fascicolo: 2, volume: 1419, anno: 1999,
pagine: 151 - 163
SICI:
0005-2736(19990715)1419:2<151:PIBAAB>2.0.ZU;2-G
Fonte:
ISI
Lingua:
ENG
Soggetto:
NATIVE MEMBRANES; FLUIDITY; CHOLESTEROL; TOXICITY; MECHANISMS; BILAYERS; INSECTICIDES; MODEL; DIPALMITOYLPHOSPHATIDYLCHOLINE; LINDANE;
Keywords:
alpha-endosulfan; beta-endosulfan; lipid membrane; phase diagram; fluorescence polarization; differential scanning calorimetry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Madeira, VMC Ctr Neurociencias, Dept Zool, P-3000 Coimbra, Portugal Ctr Neurociencias Coimbra Portugal P-3000 Coimbra, Portugal
Citazione:
R.A. Videira et al., "Perturbations induced by alpha- and beta-endosulfan in lipid membranes: a DSC and fluorescence polarization study", BBA-BIOMEMB, 1419(2), 1999, pp. 151-163

Abstract

The interaction of alpha- and beta-endosulfan isomers with lipid bilayers was searched by differential scanning calorimetry (DSC) and fluorescence polarization of 2-, 6- and 12-(9-anthroyloxy) stearic acids (2-AS, 6-AS and 12-AS) and 16-(9-anthroyloxy) palmitic acid (16-AP). Both endosulfan isomers, at insecticide/lipid molar ratios ranging from 1/40 to 1/1, shift the phase transition midpoint to lower temperature values and broaden the transition profile of dipalmitoylphosphatidylcholine (DPPC) bilayers. At insecticide/lipid molar ratios of 1/40, the isomers fully abolish the bilayer pretransition. Conversely to beta-endosulfan, alpha-endosulfan promotes a new phase transition, centered at 35.4 degrees C, in addition to the main phase transition of DPPC. Therefore, the alpha-isomer may undergo a heterogeneous distribution in separate domains in the plane of the membrane, whereas the beta-isomer may undergo a homogeneous distribution. Fluorescence polarizationdata indicate that alpha-endosulfan increases the lipid structural order in the regions probed by 2-AS and decreases it in the regions probed by 6-AS, 12-AS and 16-AP. On the other hand, the beta-isomer produces disordering effects in the upper regions of the bilayers, probed by 2-AS, and ordering in deeper regions, probed by 6-AS, 12-AS and 16-AP, mainly in the gel phase. The incorporation of cholesterol into DPPC bilayers progressively decreases the effects of beta-isomer which are vanished at 20 mol% cholesterol. However, this and higher cholesterol concentrations did not prevent alpha-endosulfan membrane interaction, as revealed by DSC and fluorescence polarization. The distinct effects promoted by alpha- and beta-endosulfan are discussed in terms of molecular orientation and positioning within the bilayer. Apparently, the alpha-isomer preferentially locates closer to the phospholipid headgroups whereas the beta-isomer distributes in deeper domains of the bilayer. (C) 1999 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 15/08/20 alle ore 19:58:56