Cryoprotection and Cryosterilization Effects of Type I Antifreeze Protein on E. coli cells

• Published in: Biocontrol Science Vol. 14; no. 2; pp. 49 - 54
• Main Authors: KAWAHARA, HIDEHISA, HIGA, SAKURA, TATSUKAWA, HIROYUKI, OBATA, HITOSHI
• Format: Journal Article
• Language: English
• Published: Japan The Society for Antibacterial and Antifungal Agents, Japan 01.01.2009; Japan Science and Technology Agency
• Subjects: Antifreeze protein; Antifreeze Proteins, Type I - pharmacology; Atmospheric Pressure; Cryopreservation; Cryopreservation - methods; Cryoprotection; Cryoprotective Agents - pharmacology; Cryosterilization; Escherichia coli; Escherichia coli - drug effects; Escherichia coli - physiology; Recombinant Proteins - pharmacology; Sterilization - methods
• ISSN: 1342-4815; 1884-0205
• DOI: 10.4265/bio.14.49

To establish the effects of type I antifreeze protein (AFP) on E. coli cells, we have focused on the survival rate of the E. coli cells using type I AFP at various concentrations under rapid cooling conditions using liquid N2 at atmospheric or low pressure. The survival rate of E. coli was enhanced by the addition of type I AFP at a concentration of 10 μg/ml, and its value shifted from 0.73% to 2.96%. When the concentration of type I AFP was 100 μg/ml, the cell survival rate markedly decreased to 0.090%. This low survival rate was further decreased (0.022%) by the application of the same freeze-thaw treatment for four times. Also, the effect of type I AFP as a bactericidal agent did not vary according to the varying initial cell densities from 104 to 108 cells/ml. Furthermore, the effects of using type I AFP at 1.0 MPa with N2 gas under conditions of low pressure and low oxygen tension using a simple device were examined. When the actions of type I AFP as a cryoprotectant were stimulated, the survival rate of the E. coli cells increased to 57.8%. In addition, the bactericidal effect of type I AFP at 100 μg/ml of protein concentration could also be enhanced. The survival rate using 100 μg/ml of type I AFP under low pressure was 0.35% of that using 10 μg/ml under the same conditions. This is the first report on the cryoprotectant and cryosterilization effects of type I AFP of E. coli cells under various conditions.