Determination of death characteristics of wildtype and DeltaCOX10 strains of Saccharomyces cerevisiae in the presence of isoflurane.

摘要

The anesthetic, isoflurane, has been reported to induce cell death in yeast with cytochrome oxidase (COX or Complex IV) deficiencies. COX is the terminal enzyme complex in the mitochondrial respiratory chain whose structure and function is coded by both nuclear and mitochondrial genes. One of the nuclear genes, COX10, an assembly factor essential for the biogenesis of COX that plays a critical role in the beginning of the mitochondrial heme A biosynthesis pathway. Deletions in this gene have resulted in the presentation of multiple human diseases such as Leigh's Syndrome, sensorineural hearing loss, fatal hypertrophic cardiomyopathy, tubulopathy and leukodystrophy. 84-87 The purpose of this study was to determine the death characteristics of wild-type and Deltacox10 strains of Saccharomyces cerevisiae in the presence of isoflurane. The Deltacox10 strain is homologous to the human COX10 gene that is mutated in the mitochondrial diseases mentioned above. For this study both wild-type and Deltacox10 yeast strains were exposed to various concentrations (0.05% v/v, 0.1% v/v, 0.5% v/v) of isoflurane for 200 minutes. After the exposure time, cells were both plated onto Yeast-Peptone-Dextrose (YPD) media for cell viability as well as run through a yeast terminal deoxynucleotidyl transferase dUTP nick-end-labeling (TUNEL)-assay to determine DNA fragmentation, a hallmark sign of apoptosis. This study revealed that both wild-type and Deltacox10 yeast strains are decreasingly viable when exposed to concentrations of isoflurane above 0.1% v/v. Also, the researchers saw an increasing percentage of TUNEL-positive phenotypes with increasing concentrations of isoflurane. In conclusion the researchers were able to confirm with prior research that isoflurane may have detrimental effects to both wild-type and mutant strains of cells in humans. Although apoptosis was noted the results were not significant when compared to non-treated controls. Therefore we cannot imply that cellular death is through apoptotic pathways.