Determination of Intracellular Vitrification Temperatures for Unicellular Micro Organisms under Conditions Relevant for Cryopreservation

PLoS One. 2016 Apr 7;11(4):e0152939. doi: 10.1371/journal.pone.0152939. eCollection 2016.

Abstract

During cryopreservation ice nucleation and crystal growth may occur within cells or the intracellular compartment may vitrify. Whilst previous literature describes intracellular vitrification in a qualitative manner, here we measure the intracellular vitrification temperature of bacteria and yeasts under conditions relevant to cryopreservation, including the addition of high levels of permeating and nonpermeating additives and the application of rapid rates of cooling. The effects of growth conditions that are known to modify cellular freezing resistance on the intracellular vitrification temperature are also examined. For bacteria a plot of the activity on thawing against intracellular glass transition of the maximally freeze-concentrated matrix (Tg') shows that cells with the lowest value of intracellular Tg' survive the freezing process better than cells with a higher intracellular Tg'. This paper demonstrates the role of the physical state of the intracellular environment in determining the response of microbial cells to preservation and could be a powerful tool to be manipulated to allow the optimization of methods for the preservation of microorganisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cryopreservation*
  • Freezing*
  • Lactobacillus delbrueckii / metabolism*
  • Saccharomyces cerevisiae / metabolism*

Grants and funding

This study was supported by the National Institute of Agronomic Research (Paris, France). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.