In situ light responses of the proteorhodopsin-bearing Antar

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TitleIn situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torquesAbstractProteorhodopsin (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. © The Author(s) 2017.

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1st AuthorBurr, D. AuthorBurr, D.Martin, A.Maas, E.Ryan, K.Year2017JournalISME JournalVolume11Number9Pages2155-2158DOI10.1038/ismej.2017.65URLhttps://www.scopus.com/inward/recor.....398e4dc36de95520adb028864PublisherNature Publishing GroupKeywordsamino acidbacteriumbiomineralizationcells and cell componentscomplexityenvironmental stressincubationlight effectprokaryoteproteinsea icesolar power, Bacteria (microorganisms)ProkaryotaPsychroflexusPsychroflexus torquis, bacterial proteinproteorhodopsinrhodopsin, AntarcticaFlavobacteriaceaegeneticsice coverisolation and purificationlightmetabolismmicrobiologyphylogenyradiation response, Antarctic RegionsBacterial ProteinsFlavobacteriaceaeIce CoverLightPhylogenyRhodopsins, Microbial

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CitationBurr, D., Martin, A., Maas, E. and Ryan, K. (2017). In situ light responses of the proteorhodopsin-bearing Antarctic sea-ice bacterium, Psychroflexus torques. ISME Journal, 11(9): 2155-2158Antarctica NZ supported?YesNZARI?No