CORRELATION BETWEEN POSSESSION OF A RESPIRATION-DEPENDENT NA+ PUMP AND NA+ REQUIREMENT FOR GROWTH OF MARINE-BACTERIA

The possession of a respiration-dependent primary sodium pump and the requirement of Na+ for growth were investigated in bacterial isolates from marine environments. The bacteria in which NADH oxidase specifically required Na+ for maximum activity were believed to possess a primary sodium pump. All bacteria that failed to grow without the addition of NaCl possessed a primary Na+ pump. All bacteria that had no primary Na+ pump grew without additional NaCl. The primary Na+ pump seems to be involved in the Na+ requirement of marine bacteria, and this can be regarded as a criterion for the definition of marine bacteria.