[14C]Dicofol association to cellular components of Azospirillum lipoferum

The bacterium Azospirillum lipoferum is able to survive in high concen-trations of the organochlorine acaricide dicofol [1,1-bis-(4-chlorophenyl)-2,2,2-trichloroethanol]. It accumulates this chemical in the cell envelope where it is protected against hydrolysis. We investigated the nature of cell envelope molecules with which [¹⁴C]dicofol is associated; no indication of [¹⁴C]dicofol–saccharide bonds was found. We concluded that about 80% of the total [¹⁴C]dicofol found in the cells was associated with lipids and the remaining 20% with proteins. Electrophoresis did not indicate any correlation of a specific protein band with [¹⁴C]dicofol radioactivity peaks. After Folch partition, [¹⁴C]dicofol distribution in TLC analysis showed 60% of [¹⁴C]dicofol–lipid bonds related to neutral lipids, 20% to phospholipids and the remaining 20% of the bonds associated with other lipids. Experimental results suggested that [¹⁴C]dicofol associates mainly with membrane domains near proteins and that this association influences membrane fluidity as well as enzymatic activity. © 1998 SCI