The Ribonucleotide Sequence of 5S rRNA from Two Strains of Deep-Sea Barophilic Bacteria

1 Department of Microbiology, University of Maryland, College Park, Maryland 20742, USA 2 Department of Biochemical and Biophysical Sciences, University of Houston, Central Campus, Houston, Texas 77004, USA ABSTRACT Deep-sea bacteria were isolated from the digestive tract of animals inhabiting depths of 5900 m in the Puerto Rico Trench and 4300 m near the Walvis Ridge. Growth of two bacterial strains was measured in marine broth and in solid media under a range of pressures and temperatures. Both strains were barophilic at 2 °C (±1 °C) with an optimal growth rate of 0.22 h -1 at a pressure 30% lower than that encountered in situ. At 1 atm they grew at temperatures ranging from 1.2 to 18.2 °C (±0.3 °C), while in situ pressures increased the upper temperature limit to 23.3 °C. Both strains were identified as members of the genus Vibrio , based on standard taxonomic tests and mol % G + C values (47.0 and 47.1). Ribonucleotide sequences determined for 5S ribosomal RNA from each strain confirmed relationship to the Vibrio-Photobacterium group, as represented by V. harveyi and P. phosphoreum , but the barophiles were clearly distinct from these species. Secondary structure conformed to the established model for eubacterial 5S rRNA. Present address: Chesapeake Bay Institute and Department of Biology, The Johns Hopkins University, 4800 Atwell Road, Shady Side, Maryland 20764, USA.