Biology subjects

Canizal-Garcia, M.

Publications and source records attributed to Canizal-Garcia, M..

3 recordsLinked to original sources

bioRxiv2018

Influence of SNF1 complex on growth, glucose metabolism and mitochondrial respiration of Saccharomyces cerevisiae

The switch of mitochondrial respiration to fermentation as the main pathway to produce ATP through the increase of glycolytic flux is known as the Crabtree effect. The elucidation of the molecular mechanism of the Crabtree effect may have important applications in ethanol production and lay the groundwork for the Warburg effect, which is essential in the molecular etiology of cancer. A key piece in this mechanism could be Snf1p, which is a protein that participates in the nutritional response that includes glucose metabolism. Thus, this work aimed to recognize the role of the SNF1 complex on the glycolytic flux and mitochondrial respiration, to gain insights about its relationship with the Crabtree effect. Herein, we found that in Saccharomyces cerevisiae cells grown at 1% glucose, mutation of SNF1 gene decreased glycolytic flux, increased NAD(P)H, enhanced HXK2 gene transcription, and decreased mitochondrial respiration. Meanwhile, the same mutation increased the mitochondrial respiration of cells grown at 10% glucose. Moreover, SNF4 gene deletion increased respiration and growth at 1% of glucose. In the case of the GAL83 gene, we did not detect any change in mitochondrial respiration or growth. Altogether, these findings indicate that SNF1 is vital to switch from mitochondrial respiration to fermentation.

biochemistry↗

bioRxiv2017

Glutathione levels influence chronological life span of Saccharomyces cerevisiae in a glucose-dependent manner

Diet plays a key role in determining the longevity of the organisms since it has been demonstrated that glucose restriction increases lifespan whereas a high-glucose diet decreases it. However, the molecular basis of how diet leads to the aging process is currently unknown. We propose that the quantity of glucose that fuels respiration influences ROS generation and glutathione levels, and both chemical species impact in the aging process. Herein, we provide evidence that mutation of the gene GSH1 diminishes glutathione levels. Moreover, glutathione levels were higher with 0.5% than in 10% glucose in the gsh1{Delta} and WT strains. Interestingly, the chronological life span (CLS) was lowered in the gsh1{Delta} strain cultured with 10% glucose but not under dietary restriction. The gsh1{Delta} strain also showed an inhibition of the mitochondrial respiration in 0.5 and 10% of glucose but only increased the H2O2 levels under dietary restriction. These results correlate well with the GSH/GSSG ratio, which showed a decrease in gsh1{Delta} strain cultured with 0.5% glucose. Altogether these data indicate that glutathione has a major role in the function of electron transport chain (ETC) and is essential to maintain life span of Saccharomyces cerevisiae in 10% glucose.

biochemistry↗

bioRxiv2017

Resveratrol Induces Mitochondrial Dysfunction And Decreases Chronological Life Span Of Saccharomyces cerevisiae In A Glucose-Dependent Manner

A broad range of health benefits have been attributed to resveratrol (RSV) supplementation in mammalian systems, including the increases in longevity. Nonetheless, despite the growing number of studies performed with RSV, the molecular mechanism by which it acts still remains unknown. Recently, it has been proposed that inhibition of the oxidative phosphorylation activity is the principal mechanism of RSV action. This mechanism suggests that RSV might induce mitochondrial dysfunction resulting in oxidative damage to cells with a concomitant decrease of cell viability and cellular life span. To prove this hypothesis, the chronological life span (CLS) of Saccharomyces cerevisiae was studied as it is accepted as an important model of oxidative damage and aging. In addition, oxygen consumption, mitochondrial membrane potential, and hydrogen peroxide (H2O2) release were measured in order to determine the extent of mitochondrial dysfunction. The results demonstrated that the supplementation of S. cerevisiae cultures with 100 M RSV decreased CLS in a glucose-dependent manner. At high-level glucose, RSV supplementation increased oxygen consumption during the exponential phase yeast cultures, but inhibited it in chronologically aged yeast cultures. However, at low-level glucose, oxygen consumption was inhibited in yeast cultures in the exponential phase as well as in chronologically aged cultures. Furthermore, RSV supplementation promoted the polarization of the mitochondrial membrane in both cultures. Finally, RSV decreased the release of H2O2 with high-level glucose and increased it at low-level glucose. Altogether, this data supports the hypothesis that RSV supplementation decreases CLS as a result of mitochondrial dysfunction and this phenotype occurs in a glucose-dependent manner.

biochemistry↗