The effect of osmotic stress on the biophysical behavior of the Bacillus subtilis membrane studied by dynamic and steady-state fluorescence anisotropy.
Arch Biochem Biophys
; 408(2): 220-8, 2002 Dec 15.
Article
em En
| MEDLINE
| ID: mdl-12464275
The thermotropic behavior of intact bacterial membranes and vesicles prepared from total and polar lipids isolated from Bacillus subtilis cultures grown at 37 degrees C in normal (LB) and hyperosmotic (LBN) conditions was studied using 1,6-diphenyl-1,3,5-hexatriene (DPH), 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate (TMA-DPH), and 2-diethylamino-6-lauroyl-naphthalene (Laurdan) as fluorescent probes. No phase transition of bulk lipids was observed in these preparations at the range of temperature studied. The anisotropy values (r(s)) for DPH and TMA-DPH in purified membranes showed significant differences between the LB and LBN conditions, suggesting that there was an increase in membrane packing during the adaptation to osmotic stress. Furthermore, generalized polarization (GP) parameters for Laurdan indicated small but significant changes in water relaxation at the membrane hydrophobic/hydrophilic interface. Membrane preparations showed r(s) higher values than those of lipid vesicles and a higher temperature dependence of the Laurdan GP parameter. This fact indicates that membrane proteins increase the lipid packing and keep the membrane more sensitive to temperature changes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bacillus subtilis
/
Membrana Celular
/
Difenilexatrieno
/
Polarização de Fluorescência
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Estados Unidos