title: Growth of Carnobacterium spp. from permafrost under low pressure, temperature, and anoxic atmosphere has implications for Earth microbes on Mars.
abstract: The ability of terrestrial microorganisms to grow in the near-surface environment of Mars is of importance to the search for life and protection of that planet from forward contamination by human and robotic exploration. Because most water on present-day Mars is frozen in the regolith, permafrosts are considered to be terrestrial analogs of the martian subsurface environment. Six bacterial isolates were obtained from a permafrost borehole in northeastern Siberia capable of growth under conditions of low temperature (0 °C), low pressure (7 mbar), and a CO(2)-enriched anoxic atmosphere. By 16S ribosomal DNA analysis, all six permafrost isolates were identified as species of the genus Carnobacterium, most closely related to C. inhibens (five isolates) and C. viridans (one isolate). Quantitative growth assays demonstrated that the six permafrost isolates, as well as nine type species of Carnobacterium (C. alterfunditum, C. divergens, C. funditum, C. gallinarum, C. inhibens, C. maltaromaticum, C. mobile, C. pleistocenium, and C. viridans) were all capable of growth under cold, low-pressure, anoxic conditions, thus extending the low-pressure extreme at which life can function.
authors.affiliation: Department of Microbiology and Cell Science, Space Life Sciences Laboratory, University of Florida, Merritt Island, FL 32953, USA. WLN@ufl.edu
authors.forename: Wayne L
authors.initials: WL
authors.lastname: Nicholson
authors.forename: Kirill
authors.initials: K
authors.lastname: Krivushin
authors.forename: David
authors.initials: D
authors.lastname: Gilichinsky
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Schuerger
mesh_terms: D000693:Anaerobiosis; D001274:Atmospheric Pressure; D001483:Base Sequence; D056573:Carnobacterium / Q000235:genetics* / Q000254:growth & development*; D016000:Cluster Analysis; D004275:DNA, Ribosomal / Q000235:genetics; D018559:Exobiology; D005118:Extraterrestrial Environment; D018535:Mars; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012800:Siberia; D012988:Soil Microbiology; D013045:Species Specificity; D013696:Temperature
chemical_list: D004275:DNA, Ribosomal