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Regulation of proteorhodopsin gene expression by nutrient limitation in the marine bacterium V ibrio sp. AND 4
Author(s) -
Akram Neelam,
Palovaara Joakim,
Forsberg Jeremy,
Lindh Markus V.,
Milton Debra L.,
Luo Haiwei,
González José M.,
Pinhassi Jarone
Publication year - 2013
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12085
Subject(s) - biology , context (archaeology) , bacteria , vibrio , gene expression , stationary phase , gene , nutrient , plankton , regulation of gene expression , marine bacteriophage , microbiology and biotechnology , ecology , genetics , paleontology , chemistry , chromatography
Summary Proteorhodopsin ( PR ), a ubiquitous membrane photoprotein in marine environments, acts as a light‐driven proton pump and can provide energy for bacterial cellular metabolism. However, knowledge of factors that regulate PR gene expression in different bacteria remains strongly limited. Here, experiments with V ibrio sp. AND 4 showed that PR phototrophy promoted survival only in cells from stationary phase and not in actively growing cells. PR gene expression was tightly regulated, with very low values in exponential phase, a pronounced peak at the exponential/stationary phase intersection, and a marked decline in stationary phase. Thus, PR gene expression at the entry into stationary phase preceded, and could therefore largely explain, the stationary phase light‐induced survival response in AND 4. Further experiments revealed nutrient limitation, not light exposure, regulated this differential PR expression. Screening of available marine vibrios showed that the PR gene, and thus the potential for PR phototrophy, is found in at least three different clusters in the genus V ibrio . In an ecological context, our findings suggest that some PR ‐containing bacteria adapted to the exploitation of nutrient‐rich micro‐environments rely on a phase of relatively slowly declining resources to mount a cellular response preparing them for adverse conditions dispersed in the water column.