title: Controlled rate cooling of fungi using a stirling cycle freezer.
abstract: BACKGROUND
  The use of a Stirling cycle freezer for cryopreservation is considered to have significant advantages over traditional methodologies including N2 free operation, application of low cooling rates, reduction of sample contamination risks and control of ice nucleation.
  
  
  OBJECTIVE
  The study assesses the suitability of an 'N2-free' Stirling Cycle controlled rate freezer for fungi cryopreservation.
  
  
  METHODS
  In total, 77 fungi representing a broad taxonomic coverage were cooled using the N2 free cooler following a cooling rate of -1 degrees C min(-1). Of these, 15 strains were also cryopreserved using a traditional 'N2 gas chamber' controlled rate cooler and a comparison of culture morphology and genomic stability against non-cryopreserved starter cultures was undertaken.
  
  
  RESULTS
  In total of 75 fungi survived cryopreservation, only a recalcitrant Basidiomycete and filamentous Chromist failed to survive. No changes were detected in genomic profile after preservation, suggesting that genomic function is not adversely compromised as a result of using 'N2 free' cooling.
  
  
  CONCLUSIONS
  The results demonstrate the potential of 'N2-free' cooling for the routine cryopreservation of fungi in Biological Resource Centres.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Ryan
authors.forename: Daiva
authors.initials: D
authors.lastname: Kasulyte-Creasey
authors.forename: Anthony
authors.initials: A
authors.lastname: Kermode
authors.forename: Shwe Phue
authors.initials: SP
authors.lastname: San
authors.forename: Alan G
authors.initials: AG
authors.lastname: Buddie
mesh_terms: D018070:Biological Specimen Banks; D015925:Cryopreservation / Q000295:instrumentation* / Q000379:methods; D021901:DNA, Intergenic; D005658:Fungi / Q000502:physiology*; D005819:Genetic Markers; D016681:Genome, Fungal; D042822:Genomic Instability; D050296:Microbial Viability; D009584:Nitrogen; D013045:Species Specificity; D020080:Tandem Repeat Sequences
chemical_list: D021901:DNA, Intergenic; D005819:Genetic Markers; D009584:Nitrogen