Alterations in Membrane Phospholipid Fatty Acids of Gram-Positive Piezotolerant Bacterium Sporosarcina sp. DSK25 in Response to Growth Pressure |
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Authors: | Jiani Wang Jiangtao Li Shamik Dasgupta Li Zhang Mikhail Y. Golovko Svetlana A. Golovko Jiasong Fang |
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Affiliation: | 1. State Key Laboratory of Marine Geology, Tongji University, Shanghai, People’s Republic of China 2. State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Sciences, China University of Geosciences, Wuhan, 430074, People’s Republic of China 3. Department of Basic Sciences, University of North Dakota, Grand Forks, ND, 58202, USA 4. Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
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Abstract: | Pressure is an important thermodynamic property of the ocean and the deep biosphere that affects microbial physiology and biochemistry. Here, we report on our investigation of the response of Gram-positive piezotolerant bacterium Sporosarcina sp. DSK25 to hydrostatic pressure. Strain DSK25 responded in an adaptive manner to upshifts of growth pressure and showed systematic changes in phospholipid fatty acids. As the pressure increased from 0.1 to 10 MPa (Megapascal), unsaturated fatty acids in DSK25 increased from 21.7 to 31.1 % of total fatty acids, while the level of iso- and anteiso-branched fatty acids remained unchanged. At higher pressures (30, 50, and 60 MPa), the amount of unsaturated fatty acids decreased, and that of anteiso-branched fatty acids increased from 34.4 to 49.9 % at the expense of iso-branched fatty acids. For the first time, two polyunsaturated fatty acids (PUFA), 18:2n-6 and 18:2n-x, with the latter having much higher abundance than the former, were identified in DSK25. The concentration of the PUFA increased with growth pressure. These results indicate the involvement of unsaturated and methyl-branched fatty acids in the modulation of bacteria membrane fluidity and function over environmentally relevant parameter (pressure). Piezotolerant bacterium Sporosarcina sp. DSK25 appears to utilize two regulatory mechanisms for adaptation to high pressure, a rapid-responding mechanism on transient scale, expressed as increased biosynthesis of monounsaturated fatty acids, and a long-term adaptation mechanism in increased synthesis of anteiso-branched and polyunsaturated fatty acids. Our results further suggest that Gram-positive piezophilic bacteria respond differently than Gram-negative bacteria in adaptation to high pressure. |
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Keywords: | Adaptation Gram‐positive bacteria Growth pressure Phospholipid fatty acids Piezophilic bacteria Sporosarcina sp. DSK25 |
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