[The role of membrane processes in Au(III) and Au(0) accumulation by bacteria]

The role of structural and functional factors in the processes of the bacterial cell interaction with colloid Au (0) and ionic Au (III) states has been investigated. It is shown that the bacterial walls of Bacillus sp. 4368 aggregating with colloid gold contain glycoprotein with isoelectric point 11. Glycoprotein from cell walls indifferent to colloid gold strain (Bacillus subtilis 168) has pHiso = 5. At the same time the cells of both strains accumulate Au (III) introduced into a medium in the form of tetrachloroaurate. The process is energy-dependent because it is suppressed by azide, uncouplers of oxidative phosphorylation and dicyclohexyl carbodiimide (DCCD). The role of ATPase of Au (III) accumulation has been studied on Bacillus sp. 4368 plasma membrane vesicles. The ATPase activity is inhibited by 70, 50 and 35-50% by vanadate, DCCD and Au (III), respectively, but it does not change in the presence of dinitrophenol and NaN3. ATP but not ADP and AMP stimulated the Au (III) accumulation by membrane vesicles and prevents the inhibitory action of azide but neither of DNP or DCCD. In the energized state membrane vesicles link gold sol particles. It has been assumed that the Au (III) accumulation is associated with the functioning of transmembrane potential generators, the metal being localized on the membrane surface.