Effects of different frequencies of physical training on electron transport chain and oxidative damage in healthy mice

The present study investigated the effect of different frequencies (three and five times a week) on electron transport chain and oxidative stress after 8 weeks of run training. Methods: Eighteen male mice (CF1, 30-35g) were distributed into the following groups (n=6): untrained (UT); trained three-time per week (T3) and trained five- time per week (T5). All training sessions were at the same intensity and duration (45min/day) in a treadmill for small animals. Forty-eight hours after the last training session, the animals were killed by decapitation and quadriceps (red portion) was removed and stored at -70ºC. Succinate dehydrogenase (SDH), complexes I, II, II-III, IV and hydroperoxides were measured. Results: Training sessions for five times per week were more effective in increasing the mitochondrial respiratory chain enzyme activities (SDH, complexes I, II, II-III, IV) as well as in decreasing the formation hydroperoxides than sessions performed for three times training per week (p<0.05). Conclusion: Our findings clearly showed that a higher the frequency of training session promotes a greater activity of the electron transport chain and consequently reduces the oxidative stress in healthy animals.(AU)

Respiratory-chain enzyme activities in isolated mitochondria of lymphocytes from patients with Parkinson's disease: preliminary study.

BACKGROUND: Evidence suggests that mitochondrial dysfunction stimulates the production of reactive oxygen species (ROS) that promote neural cell death in stroke and in Parkinson's disease. The sites of mitochondrial ROS production are not established but are generally believed to be located within the electron transport chain. AIMS: We studied the mitochondrial respiratory chain enzymes function from human circulating lymphocytes. SETTING AND DESIGN: Open study. MATERIALS AND METHODS: Forty patients with Parkinson's disease (PD) with 30 age-matched control subjects were selected in this study. The patients had received no treatment before the study was conducted. STATISTICAL ANALYSIS: The data from patients and controls were compared using two-tailed student's t-test and values were expressed as means +/- standard deviation (SD). RESULTS: Respiratory complex I + III and IV activities were significantly lower (P < 0.001) in patients than in control subjects. CONCLUSIONS: The use of lymphocytes for investigating the respiratory chain enzymes provides an easy, noninvasive method to assess mitochondrial function in patients with PD. Furthermore, our study supports the hypothesis that a biochemical defect in the respiratory chain may be involved in the pathogenesis of PD.

Energy production in Entamoeba histolytica: new perspectives in rational drugs design

The amebicidal action of metronidazol is activated when the enzyme pyruvate: ferredoxin oxido reductase transfers reducing equivalents to the nitro group of the drug. The enzyme is present in Entanoeba histolytica and other anaerobic parasites like Giardia and Trichomonas that lack mitochondria. The selectivity of the drug can be ascribed to the absence of the reductasa in the human host. E. histolytica possesses other enzymes involved in glucose catabolism that are interesting for the rational desing of new drugs. It has glycolytic enzymes that are important for the production of energy like phosphofructokinase, pyruvate phosphate dikinase, phosphoenolpyruvate carboxytransphosphorylase and thiokinase, which use pyrophosphate as a phosphate donor and have no human counterparts. The first part of this article describes the reactions by which E. histolytica obtains energy from glucose degradation, and includes recent advances in thecloning of genes for the various participating enzymes. The second part shows an alternative view for the study of target enzymes that are unique to the parasite, and indicates their importance in therapautic research