title: Comparison of cryopreservation methods for the long term storage of the marine diatom Haslea ostrearia (simonsen).
abstract: Long term maintenance of microalgal strains by serial subculturing is often expensive and time-consuming. Alternative methods, such as cryopreservation, present several benefits and thus seem more relevant. Our study aimed at comparing two cryopreservation procedures applied to the marine diatom Haslea ostrearia (Simonsen): (1) a two-step freezing method in liquid media using 5%, 10% and 20% MeOH, Me₂SO or Glycerol, and (2) an immobilization-dehydration method consisting in an algal cell entrapped in 0.7 M sucrose dehydrated and air-flow desiccated calcium alginate beads before "direct" or "two-step" freezing. Our results showed that the cryopreservation of H. ostrearia was feasible. With the two-step freezing protocol only Me₂SO maintained cell viability without contamination but the low percentage of viability (<10%) prevents its use. Conversely, the immobilization-dehydration methods tested in this study were effective. Average viability of 57% and 77% were obtained with the "direct" and the "two step" cooling assays respectively, ensuring preservation of the genetic traits of H. ostrearia.
authors.affiliation: Université de Bretagne Occidentale-UBO, Institut Universitaire Européen de la Mer-IUEM, LEMAR UMR 6539, Technopôle Brest-Iroise, Rue Dumont d'Urville, 29280 Plouzané, France.
authors.forename: Anaëlle
authors.initials: A
authors.lastname: Tanniou
authors.forename: Vincent
authors.initials: V
authors.lastname: Turpin
authors.forename: Thierry
authors.initials: T
authors.lastname: Lebeau
mesh_terms: D002470:Cell Survival / Q000187:drug effects*; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology*; D003681:Dehydration; D003890:Desiccation / Q000379:methods*; D017377:Diatoms / Q000378:metabolism*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005615:Freezing; D005990:Glycerol / Q000494:pharmacology; D000432:Methanol / Q000494:pharmacology
chemical_list: D003451:Cryoprotective Agents; D005990:Glycerol; D000432:Methanol; D004121:Dimethyl Sulfoxide