Stimulation of strontium accumulation in linoleate-enriched Saccharomyces cerevisiae is a result of reduced Sr2+ efflux

Appl Environ Microbiol. 1999 Mar;65(3):1191-7. doi: 10.1128/AEM.65.3.1191-1197.1999.

Abstract

The influence of modified plasma membrane fatty acid composition on cellular strontium accumulation in Saccharomyces cerevisiae was investigated. Growth of S. cerevisiae in the presence of 1 mM linoleate (18:2) (which results in 18:2 incorporation to approximately 70% of total cellular and plasma membrane fatty acids, with no effect on growth rate) yielded cells that accumulated Sr2+ intracellularly at approximately twice the rate of S. cerevisiae grown without a fatty acid supplement. This effect was evident over a wide range of external Sr2+ concentrations (25 microM to 5 mM) and increased with the extent of cellular 18:2 incorporation. Stimulation of Sr2+ accumulation was not evident following enrichment of S. cerevisiae with either palmitoleate (16:1), linolenate (18:3) (n-3 and n-6 isomers), or eicosadienoate (20:2) (n-6 and n-9 isomers). Competition experiments revealed that Ca2+- and Mg2+-induced inhibition of Sr2+ accumulation did not differ between unsupplemented and 18:2-supplemented cells. Treatment with trifluoperazine (TFP) (which can act as a calmodulin antagonist and Ca2+-ATPase inhibitor), at a low concentration that precluded nonspecific K+ efflux, increased intracellular Sr2+ accumulation by approximately 3.6- and 1.4-fold in unsupplemented and 18:2-supplemented cells, respectively. Thus, TFP abolished the enhanced Sr2+ accumulation ability of 18:2-supplemented cells. Moreover, the rate of Sr2+ release from Sr2+-loaded fatty acid-unsupplemented cells was found to be at least twice as great as that from Sr2+-loaded 18:2-enriched cells. The influence of enrichment with other fatty acids on Sr2+ efflux was variable. The results reveal an enhanced Sr2+ accumulation ability of S. cerevisiae following 18:2-enrichment, which is attributed to diminished Sr2+ efflux activity in these cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / pharmacology
  • Cell Membrane / chemistry*
  • Cell Membrane Permeability
  • Culture Media
  • Fatty Acids / analysis
  • Linoleic Acid / metabolism*
  • Magnesium / pharmacology
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae / metabolism*
  • Strontium / metabolism*
  • Trifluoperazine / pharmacology

Substances

  • Culture Media
  • Fatty Acids
  • Trifluoperazine
  • Linoleic Acid
  • Magnesium
  • Calcium
  • Strontium