Organophosphorous insecticide fenitrothion alters the lipid dynamics in the spider Polybetes pythagoricus high density lipoproteins. 73 37

CUNNINGHAM, M; GARCIA, C. F; GONZALEZ-BARÓ, M; GARDA, H; POLLERO, R

PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY

Aca. Press, New York

Año: 2002 vol. 73 p. 37 - 47

0048-3575

The effect of the organophosphorous liposoluble insecticide fenitothion (FS) on the lipid phase physical properties of some spider plasma lipoproteins was investigated. Two high density lipoproteins, HDL-1 and HDL-2, they slightly differ in their lipid compositions, but significanttly differ in their lipid/protein ratio and apolipoprotein compositions, were used. The rotational behaviour of the fluorescent probes DPH and DPH-PA were studied to obtain information about the lipid dynamics in the outer and inner regions respectively of the lipoproteins lipid phase. Fluorescent steady state anisotropy (rS), lifetime (t ), rotational correlation time (t r), and the limiting anisotropy (r¥ ) of these probes were measured in the lipoproteins exposed in vitro to different concentrations of FS. The results of showed the FS penetration into both plasma lipoproteins, altering the lipid dynamics in their cores as well as in the outer parts. In both lipoproteins subjected to FS action, the limiting anisotropy values were found to be increased, thus corroboting the increment of the lipid ordering. It must be pointed out that the increase of r¥ produced by FS depends on the inicial lipid order and is higher in the less ordered samples. Fluorescence lifetimes of DPH and DPH-PA indicate that FS increases the polarity of the probe environments, suggesting an enhanced water penetration into the lipoprotein lipid phase, possibly due to the induction of failures in the lipid packing. Its action, depending on the temperature and lipid packing in each region, affects differently either the inner or the outer portions of lipoproteins. Probably, all these alterations found in the lipoproteins could modify its behavior.