Title

Growth of Serratia liquefaciens under 7 mbar, 0 degrees C, and CO2-Enriched Anoxic Atmospheres

Authors

Authors

A. C. Schuerger; R. Ulrich; B. J. Berry;W. L. Nicholson

Comments

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Abbreviated Journal Title

Astrobiology

Keywords

Habitable zone; Hypobaria; Extremophiles; Special regions; Planetary; protection; MARTIAN SOIL; MICROBIOLOGICAL PROFILES; DEINOCOCCUS-RADIODURANS; SPACECRAFT SURFACES; BACILLUS-SUBTILIS; ESCHERICHIA-COLI; LOW-TEMPERATURE; LOW-PRESSURE; MARS; SURVIVAL; Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary

Abstract

Twenty-six strains of 22 bacterial species were tested for growth on trypticase soy agar (TSA) or sea-salt agar (SSA) under hypobaric, psychrophilic, and anoxic conditions applied singly or in combination. As each factor was added to multi-parameter assays, the interactive stresses decreased the numbers of strains capable of growth and, in general, reduced the vigor of the strains observed to grow. Only Serratia liquefaciens strain ATCC 27592 exhibited growth at 7 mbar, 0 degrees C, and CO2-enriched anoxic atmospheres. To discriminate between the effects of desiccation and hypobaria, vegetative cells of Bacillus subtilis strain 168 and Escherichia coli strain K12 were grown on TSA surfaces and simultaneously in liquid Luria-Bertani (LB) broth media. Inhibition of growth under hypobaria for 168 and K12 decreased in similar ways for both TSA and LB assays as pressures were reduced from 100 to 25 mbar. Results for 168 and K12 on TSA and LB are interpreted to indicate a direct low-pressure effect on microbial growth with both species and do not support the hypothesis that desiccation alone on TSA was the cause of reduced growth at low pressures. The growth of S. liquefaciens at 7 mbar, 0 degrees C, and CO2-enriched anoxic atmospheres was surprising since S. liquefaciens is ecologically a generalist that occurs in terrestrial plant, fish, animal, and food niches. In contrast, two extremophiles tested in the assays, Deinococcus radiodurans strain R1 and Psychrobacter cryohalolentis strain K5, failed to grow under hypobaric (25 mbar; R1 only), psychrophilic (0 degrees C; R1 only), or anoxic (< 0.1% ppO(2); both species) conditions.

Journal Title

Astrobiology

Volume

13

Issue/Number

2

Publication Date

1-1-2013

Document Type

Article

Language

English

First Page

115

Last Page

131

WOS Identifier

WOS:000315196100001

ISSN

1531-1074

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