Journal of Comparative Physiology B

, Volume 185, Issue 4, pp 389–400

Membrane properties of Enchytraeus albidus originating from contrasting environments: a comparative analysis

  • Karina Vincents Fisker
  • Hélène Bouvrais
  • Johannes Overgaard
  • Konrad Schöttner
  • John H. Ipsen
  • Martin Holmstrup
Original Paper

DOI: 10.1007/s00360-015-0895-7

Cite this article as:
Fisker, K.V., Bouvrais, H., Overgaard, J. et al. J Comp Physiol B (2015) 185: 389. doi:10.1007/s00360-015-0895-7

Abstract

Ectothermic animals adapted to different environmental temperatures are hypothesized to have biological membranes with different chemical and physical properties such that membrane properties are optimized for their particular thermal environments. To test this hypothesis we analyzed the composition of phospholipid fatty acids (PLFAs) in seven different populations of Enchytraeus albidus originating from different thermal environments. The seven populations differ markedly in origin (polar-temperate) and are also characterized by marked difference in cold tolerance. The dominant PLFAs of E. albidus were C20:5, C20:4 and C20:2 (53–61 % of total PLFA) followed by C18:0, C20:1 and C22:2 (17–20 % of total PLFA). As hypothesized the PLFA composition varied significantly between populations and molar percentage of several of the PLFAs (particularly C18:2) correlated with the lower lethal temperature (LT50) of the seven populations. Unsaturation ratio (UFA/SFA) and average PLFA chain length also correlated significantly with LT50, such that cold sensitive populations had a shorter chain length and a lower UFA/SFA compared to cold tolerant populations. Reconstituted membranes of the least and most cold tolerant populations were used to compare membranes’ physical properties by fluorescence anisotropy and bending rigidity. Measurements of anisotropy did not show any overall difference between populations with different cold tolerance. This could be interpreted as if E. albidus populations have achieved a similar “optimal” fluidity of the membrane with a somewhat different PLFA composition. Our study suggests that membrane lipid composition could be important for the cold tolerance of E. albidus; however, these differences are not easily differentiated in the measurements of the membranes’ physical properties. Other parameters such as accumulation of glucose for cryoprotection and energy supply may also be important components of enchytraeid freeze tolerance.

Keywords

Membrane fluidity Fluorescence anisotropy Bending rigidity Freeze tolerance Invertebrates 

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Karina Vincents Fisker
    • 1
    • 2
  • Hélène Bouvrais
    • 3
  • Johannes Overgaard
    • 2
  • Konrad Schöttner
    • 4
  • John H. Ipsen
    • 3
  • Martin Holmstrup
    • 1
    • 5
  1. 1.Section of Soil fauna Ecology and Ecotoxicology, Department of BioscienceAarhus UniversitySilkeborgDenmark
  2. 2.Zoophysiology, Department of BioscienceAarhus UniversityAarhus CDenmark
  3. 3.Department of Physics, Chemistry and Pharmacy, MEMPHYS—Center for Biomembrane PhysicsUniversity of Southern DenmarkOdense MDenmark
  4. 4.Institute of EntomologyAcademy of Sciences of the Czech RepublicČeské BudějoviceCzech Republic
  5. 5.Arctic Research CentreAarhus UniversityAarhus CDenmark

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