Proteorhodopsins (PRs) are commonly found in marine prokaryotes and allow microbes to use light as an energy source. In recent studies it was reported that PR stimulates growth and survival under nutrient-limited conditions. In this study we tested the effect of nutrient and salinity stress on the extremely psychrophilic sea-ice bacterial species Psychroflexus torquis, which possesses PR. We demonstrated for the first time that light stimulated growth occurs under conditions of salinity stress rather than nutrient limitation and that elevated salinity is related to increased growth yields, PR levels and associated proton pumping activity. PR abundance in P. torquis also is post-transcriptionally regulated by both light and salinity and thus could represent an adaptation to its sea-ice habitat. Our findings extend the existing paradigm that light provides an energy source for marine prokaryotes under stress conditions other than nutrient limitation.

Item Type:	Conference Extract
Research Division:	Biological Sciences
Research Group:	Microbiology
Research Field:	Microbiology not elsewhere classified
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Environmental Sciences
UTAS Author:	Feng, S (Mr Shi Feng)
UTAS Author:	Powell, S (Dr Shane Powell)
UTAS Author:	Wilson, RR (Dr Richard Wilson)
UTAS Author:	Bowman, JP (Associate Professor John Bowman)
ID Code:	85206
Year Published:	2013
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2013-06-18
Last Modified:	2014-04-29
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