[C-14]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-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.