Oxidative Damage and Mutation of DNA in Saccharomyces pastorianus Cells Treated with Pressurized Carbon Dioxide...

The effect of pressurized carbon dioxide microbubbles (CO₂MB) on DNA in Saccharomyces pastorianus cells was investigated. The DNA concentration extracted from S. pastorianus cells treated with CO₂MB by phenol extraction increased and decreased with the heating coil at 35 °C and at 40 and 45 °C, respectively. However, the density of DNA bands on agarose gel electrophoresis increased when using the heating coil at 40 and 45 °C. In addition, DNA fragmentation measured by quantitative PCR decreased with increasing temperature and prolonged exposure time in a heating coil. Furthermore, the generation of apurinic/apyrimidinic sites, an indicator of oxidative DNA damage, increased with increasing temperature or prolonged exposure time in a heating coil. In the phylogenetic tree constructed based on single-nucleotide polymorphisms obtained through DNA sequence analysis, S. pastorianus cells treated with CO₂MB exhibited greater divergence from untreated with increasing temperature or prolonged exposure time in a heating coil. Similarly, insertions/deletions, showed genetic variations, of S. pastorianus cells treated with CO₂MB increased with increasing temperature or prolonged exposure time in the heating coil. Therefore, these findings indicated that CO₂MB induced partial oxidative damage and mutations of DNA in S. pastorianus cells, and the phenomena were suggested to be due to the oxidative stress generated within the cells.