DISTRIBUTION OF THE PRESSURE-REGULATED OPERONS IN DEEP-SEA BACTERIA

DNA regions corresponding to portions of two different pressure-regula ted operons previously identified in two deep-sea barophilic bacteria were separately PCR amplified from a variety of deep-sea microorganism s and sequenced. With the two sets of primers employed, amplification was particularly successful from the more barophilic bacteria examined . 16S rRNA sequence analysis revealed that these bacteria are all phyl ogenetically related and belong in a sub-branch of the genus Shewanell a containing only the deep-sea Shewanella barophilic bacteria. We defi ne this sub-branch as the 'Shewanella barophile branch' containing at least two different species. Our results suggest that the DNA sequence s of the pressure-regulated operons can be regarded as marker sequence s to identify the Shewanella barophilic strains. (C) 1998 Federation o f European Microbiological Societies. Published by Elsevier Science B. V.