Isolation and characterization of the outer membrane of radiation-resistant Acinetobacter sp. FO-1.

Abstract

The outer membrane of the radiation-resistant Acinetobacter sp. FO-1 was isolated by sucrose density-gradient centrifugation after disruption of bacterial cells by shaking with glass beads in a Braun Cell Homogeniser. The characteristics of the outer membrane were examined by enzymatic, chemical and electrophoretic analysis. The isolated outer membrane clearly differed from the inner membrane in the lipid-phosphorus and 2-keto-3-deoxyoctonate to protein ratios and in the enzyme activity of adenosine triphosphate. The protein pattern of the outer membrane was determined by SDS-PAGE analysis. It showed twenty-five protein bands containing two major proteins with apparent approximate molecular weights of 39,000 and 42,000 daltons. The former was modified by heating. The latter was unmodified. These results were compared with the type strain of Acinetobacter calcoaceticus, ATCC 23055.