Energy starved Candidatus Pelagibacter ubique substitutes light-mediated ATP production for endogenous carbon respiration.

ABSTRACT: Previous studies have demonstrated that Candidatus Pelagibacter ubique, a member of the SAR11 clade, constitutively expresses proteorhodopsin (PR) proteins that can function as light-dependent proton pumps. However, exposure to light did not significantly improve the growth rate or final cell densities of SAR11 isolates in a wide range of conditions. Thus, the ecophysiological role of PR in SAR11 remained unresolved. We investigated a range of cellular properties and here show that light causes dramatic changes in physiology and gene expression in Cand. P. ubique cells that are starved for carbon, but provides little or no advantage during active growth on organic carbon substrates. During logarithmic growth there was no difference in oxygen consumption by cells in light versus dark. Energ

SUBMITTER: Steindler L 

PROVIDER: S-EPMC3090418 | biostudies-literature | 2011 May

REPOSITORIES: biostudies-literature