Tetrasphaera remsis sp. nov., isolated from the Regenerative Enclosed Life Support Module Simulator (REMS) air system

1 Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA 2 Lehrstuhl für Mikrobiologie und Archaeenzentrum, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany 3 California Institute of Technology, Division of Biology, 1200 East California Boulevard, Pasadena, CA 91125, USA 4 Microbial Type Culture Collection and Gene Bank (MTCC), Institute of Microbial Technology, Sector 39-A, Chandigarh, 160 036, India 5 National Research Institute of Fisheries Science, Fisheries Research Agency, Yokohama, 236-8648, Japan Correspondence Kasthuri Venkateswaran kjvenkat{at}jpl.nasa.gov Two Gram-positive, coccoid, non-spore-forming bacteria (strains 3-M5-R-4 T and 3-M5-R-7), cells of which formed diploid, tetrad and cluster arrangements, were isolated from air of the Regenerative Enclosed Life Support Module Simulator system. On the basis of 16S rRNA gene sequence similarity, these strains were shown to belong to the family Intrasporangiaceae and were related to members of the genus Tetrasphaera , with similarities to the seven known species of the genus Tetrasphaera of 96.71–97.76 %. The fatty acid profile supported affiliation of these novel isolates to the genus Tetrasphaera , although larger amounts of octadecanoic acid (C 18 : 0 ) and cis -9-octadecenoic acid (C 18 : 1 ) were observed in the isolates, thus enabling them to be differentiated from other Tetrasphaera species. In addition, DNA–DNA hybridization studies indicated that these strains belonged to a novel species that could be readily distinguished from its nearest neighbour, Tetrasphaera japonica DSM 13192 T , which had less than 20 % DNA–DNA relatedness. Physiological and biochemical tests showed few phenotypic differences, but genotypic analysis enabled these gelatin-liquefying strains to be differentiated from the seven Tetrasphaera species. The strains described in this study therefore represent a novel species, for which the name Tetrasphaera remsis sp. nov. is proposed; the type strain is 3-M5-R-4 T (=ATCC BAA-1496 T =CIP 109413 T ). Abbreviations: DAP, diaminopimelic acid; EM, electron microscope; ISS, International Space Station; REMS, Regenerative Enclosed Life Support Module Simulator Present address: Center for Environmental Biotechnology, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA. The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strai