Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures
<i>Serratia liquefaciens</i> is a cold-adapted facultative anaerobic astrobiology model organism with the ability to grow at a Martian atmospheric pressure of 7 hPa. Currently there is a lack of data on its limits of growth and metabolic activity at sub-zero temperatures found in potenti...
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MDPI AG
2021-05-01
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| Series: | Life |
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| Online Access: | https://www.mdpi.com/2075-1729/11/5/459 |
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| author | Petra Schwendner Ann N. Nguyen Andrew C. Schuerger |
| author_facet | Petra Schwendner Ann N. Nguyen Andrew C. Schuerger |
| author_sort | Petra Schwendner |
| collection | DOAJ |
| description | <i>Serratia liquefaciens</i> is a cold-adapted facultative anaerobic astrobiology model organism with the ability to grow at a Martian atmospheric pressure of 7 hPa. Currently there is a lack of data on its limits of growth and metabolic activity at sub-zero temperatures found in potential habitable regions on Mars. Growth curves and nano-scale secondary ion mass spectrometry (NanoSIMS) were used to characterize the growth and metabolic threshold for <i>S. liquefaciens</i> ATCC 27,592 grown at and below 0 °C. Cells were incubated in Spizizen medium containing three stable isotopes substituting their unlabeled counterparts; i.e., <sup>13</sup>C-glucose, (<sup>15</sup>NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, and H<sub>2</sub><sup>18</sup>O; at 0, −1.5, −3, −5, −10, or −15 °C. The isotopic ratios of <sup>13</sup>C/<sup>12</sup>C, <sup>15</sup>N/<sup>14</sup>N, and <sup>18</sup>O/<sup>16</sup>O and their corresponding fractions were determined for 240 cells. NanoSIMS results revealed that with decreasing temperature the cellular amounts of labeled ions decreased indicating slower metabolic rates for isotope uptake and incorporation. Metabolism was significantly reduced at −1.5 and −3 °C, almost halted at −5 °C, and shut-down completely at or below −10 °C. While growth was observed at 0 °C after 5 days, samples incubated at −1.5 and −3 °C exhibited significantly slower growth rates until growth was detected at 70 days. In contrast, cell densities decreased by at least half an order of magnitude over 70 days in cultures incubated at ≤ −5 °C. Results suggest that <i>S. liquefaciens</i>, if transported to Mars, might be able to metabolize and grow in shallow sub-surface niches at temperatures above −5 °C and might survive—but not grow—at temperatures below −5 °C. |
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| institution | Directory Open Access Journal |
| issn | 2075-1729 |
| language | English |
| last_indexed | 2024-03-10T11:13:39Z |
| publishDate | 2021-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Life |
| spelling | doaj.art-e25b713a55c24257876457428237aaeb2023-11-21T20:39:06ZengMDPI AGLife2075-17292021-05-0111545910.3390/life11050459Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero TemperaturesPetra Schwendner0Ann N. Nguyen1Andrew C. Schuerger2Space Life Sciences Lab, Department of Plant Pathology, University of Florida, 505 Odyssey Way, Exploration Park, Merritt Island, FL 32953, USAJacobs, NASA Johnson Space Center, Houston, TX 77058, USASpace Life Sciences Lab, Department of Plant Pathology, University of Florida, 505 Odyssey Way, Exploration Park, Merritt Island, FL 32953, USA<i>Serratia liquefaciens</i> is a cold-adapted facultative anaerobic astrobiology model organism with the ability to grow at a Martian atmospheric pressure of 7 hPa. Currently there is a lack of data on its limits of growth and metabolic activity at sub-zero temperatures found in potential habitable regions on Mars. Growth curves and nano-scale secondary ion mass spectrometry (NanoSIMS) were used to characterize the growth and metabolic threshold for <i>S. liquefaciens</i> ATCC 27,592 grown at and below 0 °C. Cells were incubated in Spizizen medium containing three stable isotopes substituting their unlabeled counterparts; i.e., <sup>13</sup>C-glucose, (<sup>15</sup>NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub>, and H<sub>2</sub><sup>18</sup>O; at 0, −1.5, −3, −5, −10, or −15 °C. The isotopic ratios of <sup>13</sup>C/<sup>12</sup>C, <sup>15</sup>N/<sup>14</sup>N, and <sup>18</sup>O/<sup>16</sup>O and their corresponding fractions were determined for 240 cells. NanoSIMS results revealed that with decreasing temperature the cellular amounts of labeled ions decreased indicating slower metabolic rates for isotope uptake and incorporation. Metabolism was significantly reduced at −1.5 and −3 °C, almost halted at −5 °C, and shut-down completely at or below −10 °C. While growth was observed at 0 °C after 5 days, samples incubated at −1.5 and −3 °C exhibited significantly slower growth rates until growth was detected at 70 days. In contrast, cell densities decreased by at least half an order of magnitude over 70 days in cultures incubated at ≤ −5 °C. Results suggest that <i>S. liquefaciens</i>, if transported to Mars, might be able to metabolize and grow in shallow sub-surface niches at temperatures above −5 °C and might survive—but not grow—at temperatures below −5 °C.https://www.mdpi.com/2075-1729/11/5/459Mars astrobiologypsychrotolerant bacteriaNanoSIMSisotopeshypopiezotolerant bacteria |
| spellingShingle | Petra Schwendner Ann N. Nguyen Andrew C. Schuerger Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures Life Mars astrobiology psychrotolerant bacteria NanoSIMS isotopes hypopiezotolerant bacteria |
| title | Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures |
| title_full | Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures |
| title_fullStr | Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures |
| title_full_unstemmed | Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures |
| title_short | Use of NanoSIMS to Identify the Lower Limits of Metabolic Activity and Growth by <i>Serratia liquefaciens</i> Exposed to Sub-Zero Temperatures |
| title_sort | use of nanosims to identify the lower limits of metabolic activity and growth by i serratia liquefaciens i exposed to sub zero temperatures |
| topic | Mars astrobiology psychrotolerant bacteria NanoSIMS isotopes hypopiezotolerant bacteria |
| url | https://www.mdpi.com/2075-1729/11/5/459 |
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