The bacterium Azospirillum lipoferum is able to survive in high concen
trations of the organochlorine acaricide dicofol [1,1-bis-(4-chlorophe
nyl)-2,2,2-trichloroethanol]. It accumulates this chemical in the cell
envelope where it is protected against hydrolysis. We investigated th
e nature of cell envelope molecules with which [C-14]dicofol is associ
ated; no indication of [C-14]dicofol-saccharide bonds was found. We co
ncluded that about 80% of the total [C-14]dicofol found in the cells w
as associated with lipids and the remaining 20% with proteins. Electro
phoresis did not indicate any correlation of a specific protein band w
ith [C-14]dicofol radioactivity peaks. After Folch partition, [C-14]di
cofol distribution in TLC analysis showed 60% of [C-14]dicofol-lipid b
onds related to neutral lipids, 20% to phospholipids and the remaining
20% of the bonds associated with other lipids. Experimental results s
uggested that [C-14]dicofol associates mainly with membrane domains ne
ar proteins and that this association influences membrane fluidity as
well as enzymatic activity. (C) 1998 SCI.