Expression and functioning of retinal-based proton pumps in a saltern crystallizer brine

Aharon Oren, Said Abu-Ghosh, Tal Argov, Eliahu Kara-Ivanov, Dror Shitrit, Adi Volpert, Rael Horwitz

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

We examined the presence of bacteriorhodopsin and other retinal protein pigments in the microbial community of the saltern crystallizer ponds in Eilat, Israel, and assessed the effect of the retinal-based proton pumps on the metabolic activity. The biota of the hypersaline (~309 g salts l−1) brine consisted of ~2200 β-carotene-rich Dunaliella cells and ~3.5 × 107 prokaryotes ml−1, most of which were flat, square or rectangular Haloquadratum-like archaea. No indications were obtained for massive presence of Salinibacter. We estimated a concentration of bacteriorhodopsin and bacteriorhodopsin-like pigments of 3.6 nmol l−1. When illuminated, the community respiration activity of the brine samples in which oxygenic photosynthesis was inhibited by 3-(3-4-dichlorophenyl)-1,1-dimethylurea, decreased by 40–43 %. This effect was interpreted to be the result of competition between two energy yielding systems: the bacteriorhodopsin proton pump and the respiratory chain. The results presented have important implications for the interpretation of many published data on photosynthetic and respiratory activities in hypersaline environments.

Original languageEnglish
Pages (from-to)69-77
Number of pages9
JournalExtremophiles
Volume20
Issue number1
DOIs
StatePublished - 1 Jan 2016

Bibliographical note

Publisher Copyright:
© 2015, Springer Japan.

Keywords

  • Bacteriorhodopsin
  • Community respiration
  • Haloquadratum
  • Hypersaline
  • Retinal
  • Saltern

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