Barosensitivity in Saccharomyces cerevisiae is Closely Associated with a Deletion of the COX1 Gene

Abstract

High hydrostatic pressure causes physical stress to microorganisms; therefore, this technology may be applied to food pasteurization without introducing the unfavorable effects of thermal denaturation. However, its application is limited to high-value foods because the treatment requires a robust steel vessel and expensive pressurization equipment. To reduce these costs, we studied the pasteurization of Saccharomyces cerevisiae using relatively moderate high-pressure levels. A mutant strain isolated by ultraviolet mutagenesis showed significant loss of viability under high-pressure conditions. Gene expression analysis of the mutant strain revealed that it incurred a deletion of the COX1 gene. Our results suggest that the pressure-sensitivity can readily be introduced into industrial/food microorganisms by complementing a COX1 deleted mitochondria.

Genomic and Metabolomic Analyses of a Piezosensitive Mutant of Saccharomyces cerevisiae and Application for Generation of Piezosensitive Niigata-Sake Yeast Strains

“…None of the five primer sets could provide amplification. Our previous results, in which this gene was not detected by a PCR experiment, [8] is thus attributable to the deletion of this region. No other genes or open reading frames were detected within the deleted region.…”

“…These results indicated that this mutant strain was sensitive to both HHP and thermal stresses. Transcriptome analysis, as well as phenotypic analysis, of this mutant strain suggested that the strain had deficient aerobic respiration and mitochondrial functions [8]. Moreover, PCR amplification targeting genes in the mitochondrial DNA suggested that a region of the COX1 gene, encoding the subunit I of cytochrome c oxidase, in the mitochondrial DNA was deleted in strain a924E1.…”

Molecular Responses to High Hydrostatic Pressure in Eukaryotes: Genetic Insights from Studies on Saccharomyces cerevisiae

“…CTT1 and SOD2 are also upregulated by high pressure [ 48 ]. A deletion mutant for COX1 encoding the subunit I of cytochrome c oxidase in mitochondria is also sensitive to pressure at 200 MPa [ 49 ]. Taken together, these findings indicate that high hydrostatic pressure of approximately 200 MPa is likely to exert oxidative stresses in yeast cells, and the cellular defense systems against high pressure, at least in part, converge on oxidative stress responses for “cell survival.” Consistently, our recent study indicated that the scavenging activity of superoxide anion O 2 •– by superoxide dismutase 1 (Sod1) is required for “cell growth” under a moderate growth-permissive pressure at 25 MPa [ 50 ].…”