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In situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torques


Burr, DJ and Martin, A and Maas, EW and Ryan, KG, In situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torques, ISME Journal, 11 pp. 2155-2158. ISSN 1751-7362 (2017) [Refereed Article]

Copyright Statement

© 2017 International Society for Microbial Ecology All rights reserved

DOI: doi:10.1038/ismej.2017.65


Proteorhodopsin (PR) is a wide-spread protein found in many marine prokaryotes. PR allows for the potential conversion of solar energy to ATP, possibly assisting in cellular growth and survival during periods of high environmental stress. PR utilises either blue or green light through a single amino acid substitution. We incubated the PR-bearing bacterium Psychroflexus torquis 50 cm deep within Antarctic sea ice for 13 days, exposing cultures to diurnal fluctuations in light and temperature. Enhanced growth occurred most prominently in cultures incubated under irradiance levels of ∼50 μmol photons m−2 s−1, suggesting PR provides a strong selective advantage. In addition, cultures grown under blue light yielded over 5.5 times more live cells per photon compared to green-light incubations. Because P. torquis expresses an apparently ‘green-shifted’ PR gene variant, this finding infers that the spectral tuning of PR is more complex than previously thought. This study supports the theory that PR provides additional energy to bacteria under sub-optimal conditions, and raises several points of interest to be addressed by future research.

Item Details

Item Type:Refereed Article
Keywords:Antarctica, sea ice algae, proteorhodopsin
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Microbial ecology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Martin, A (Dr Andrew Martin)
ID Code:116987
Year Published:2017
Web of Science® Times Cited:2
Deposited By:Ecology and Biodiversity
Deposited On:2017-05-26
Last Modified:2018-08-02

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