Lipoperoxidative damage to the respiratory chain proteins may account for disruption in mitochondrial electron transport chain (ETC) function and could lead to an augment in the production of reactive oxygen species (ROS). To test this hypothesis, we investigated the effects of lipoperoxidation on ETC function and cytochromes spectra of Saccharomyces cerevisiae mitochondria. We compared the effects of Fe 2+ treatment on mitochondria isolated from yeast with native (lipoperoxidation-resistant) and modified (lipoperoxidation-sensitive) fatty acid composition. Augmented sensitivity to oxidative stress was observed in the complex III-complex IV segment of the ETC. Lipoperoxidation did not alter the cytochromes content. Under lipoperoxidative conditions, cytochrome c reduction by succinate was almost totally eliminated by superoxide dismutase and stigmatellin. Our results suggest that lipoperoxidation impairs electron © Springer Science + Business Media, LLC 2009 Correspondence to: Alfredo Saavedra-Molina, saavedra@umich.mx. NIH Public Access

We studied whether mitochondrial functions and Ca 2+ metabolism were altered in Wistar Kyoto normotensive (WKY) and spontaneous hypertensive rats (SHR). Ca 2+ uptake was decreased in SHR compared to WKY rats. Accumulation of Ca 2+ was more efficient in WKY than in SHR rats. mΔΨ was lower in SHR compared to WKY rats. Basal complex IV activity was higher in SHR than WKY rats, whereas basal L-citrulline production, an indicator of nitric oxide synthesis, was decreased in SHR and dependent on Ca 2+ concentration (p < 0.05). Impact of Ca 2+ was counteracted by EGTA. These data show an age-dependent decreased mitochondrial functions in brain mitochondria during hypertension.

Diabetes mellitus (DM) is a significant risk factor for the development of cardiovascular complications. This study was undertaken to investigate the effect of chronic administration of ethanolic extract of Eryngium carlinae on glucose, creatinine, uric acid, total cholesterol, and triglycerides levels in serum of streptozotocin- (STZ-) induced diabetic rats. Triglycerides, total cholesterol, and uric acid levels increased in serum from diabetic rats. The treatment with E. carlinae prevented these changes. The administration of E. carlinae extract reduced the levels of creatinine, uric acid, total cholesterol, and triglycerides. Thus administration of E. carlinae is able to reduce hyperlipidemia related to the cardiovascular risk in diabetes mellitus.

During the mezcal fermentation process, yeasts are affected by several stresses that can affect their fermentation capability. These stresses, such as thermal shock, ethanol, osmotic and growth inhibitors are common during fermentation. Cells have improved metabolic systems and they express stress response genes in order to decrease the damage caused during the stress, but to the best of our knowledge, there are no published works exploring the effect of oxidants and prooxidants, such as H2O2 and menadione, during growth. In this article, we describe the behavior of Kluyveromyces marxianus isolated from spontaneous mezcal fermentation during oxidative stress, and compared it with that of Saccharomyces cerevisiae strains that were also obtained from mezcal, using the W303-1A strain as a reference. S. cerevisiae strains showed greater viability after oxidative stress compared with K. marxianus strains. However, when the yeast strains were grown in the presence of oxidants in the media, K. marxianus exhibited a greater ability to grow in menadione than it did in H2O2. Moreover, when K. marxianus SLP1 was grown in a minibioreactor, its behavior when exposed to menadione was different from its behavior with H2O2. The yeast maintained the ability to consume dissolved oxygen during the 4 h subsequent to the addition of menadione, and then stopped respiration. When exposed to H2O2, the yeast stopped consuming oxygen for the following 8 h, but began to consume oxygen when stressors were no longer applied. In conclusion, yeast isolated from spontaneous mezcal fermentation was able to resist oxidative stress for a long period of time.

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