Invasive and noninvasive markers of human skeletal muscle mitochondrial function.

Mitochondria are organelles that fuel cellular energy requirements by ATP formation via aerobic metabolism. Given the wide variety of methods to assess skeletal muscle mitochondrial capacity, we tested how well different invasive and noninvasive markers of skeletal muscle mitochondrial capacity reflect mitochondrial respiration in permeabilized muscle fibers. Nineteen young men (mean age: 24 ± 4 years) were recruited, and a muscle biopsy was collected to determine mitochondrial respiration from permeabilized muscle fibers and to quantify markers of mitochondrial capacity, content such as citrate synthase (CS) activity, mitochondrial DNA copy number, TOMM20, VDAC, and protein content for complex I-V of the oxidative phosphorylation (OXPHOS) system. Additionally, all participants underwent noninvasive assessments of mitochondrial capacity: PCr recovery postexercise (by 31 P-MRS), maximal aerobic capacity, and gross exercise efficiency by cycling exercise. From the invasive markers, Complex V protein content and CS activity showed the strongest concordance (Rc = 0.50 to 0.72) with ADP-stimulated coupled mitochondrial respiration, fueled by various substrates. Complex V protein content showed the strongest concordance (Rc = 0.72) with maximally uncoupled mitochondrial respiration. From the noninvasive markers, gross exercise efficiency, VO2max , and PCr recovery exhibited concordance values between 0.50 and 0.77 with ADP-stimulated coupled mitochondrial respiration. Gross exercise efficiency showed the strongest concordance with maximally uncoupled mitochondrial respiration (Rc = 0.67). From the invasive markers, Complex V protein content and CS activity are surrogates that best reflect skeletal muscle mitochondrial respiratory capacity. From the noninvasive markers, exercise efficiency and PCr recovery postexercise most closely reflect skeletal muscle mitochondrial respiratory capacity.

Skeletal muscle mitochondrial inertia is associated with carnitine acetyltransferase activity and physical function in humans.

BACKGROUNDAt the onset of exercise, the speed at which phosphocreatine (PCr) decreases toward a new steady state (PCr on-kinetics) reflects the readiness to activate mitochondrial ATP synthesis, which is secondary to Acetyl-CoA availability in skeletal muscle. We hypothesized that PCr on-kinetics are slower in metabolically compromised and older individuals and are associated with low carnitine acetyltransferase (CrAT) protein activity and compromised physical function.METHODSWe applied 31P-magnetic resonance spectroscopy (31P-MRS) to assess PCr on-kinetics in 2 cohorts of volunteers. Cohort 1 included patients who had type 2 diabetes, were obese, were lean trained (VO2max > 55 mL/kg/min), and were lean untrained (VO2max < 45 mL/kg/min). Cohort 2 included young (20-30 years) and older (65-80 years) individuals with normal physical activity and older, trained individuals. Previous results of CrAT protein activity and acetylcarnitine content in muscle tissue were used to explore the underlying mechanisms of PCr on-kinetics, along with various markers of physical function.RESULTSPCr on-kinetics were significantly slower in metabolically compromised and older individuals (indicating mitochondrial inertia) as compared with young and older trained volunteers, regardless of in vivo skeletal muscle oxidative capacity (P < 0.001). Mitochondrial inertia correlated with reduced CrAT protein activity, low acetylcarnitine content, and functional outcomes (P < 0.001).CONCLUSIONPCr on-kinetics are significantly slower in metabolically compromised and older individuals with normal physical activity compared with young and older trained individuals, regardless of in vivo skeletal muscle oxidative capacity, indicating greater mitochondrial inertia. Thus, PCr on-kinetics are a currently unexplored signature of skeletal muscle mitochondrial metabolism, tightly linked to functional outcomes. Skeletal muscle mitochondrial inertia might emerge as a target of intervention to improve physical function.TRIAL REGISTRATIONNCT01298375 and NCT03666013 (clinicaltrials.gov).FUNDINGRM and MH received an EFSD/Lilly grant from the European Foundation for the Study of Diabetes (EFSD). VS was supported by an ERC starting grant (grant 759161) "MRS in Diabetes."

Exercise training elicits superior metabolic effects when performed in the afternoon compared to morning in metabolically compromised humans.

The circadian clock and metabolism are tightly intertwined. Hence, the specific timing of interventions that target metabolic changes may affect their efficacy. Here we retrospectively compared the metabolic health effects of morning versus afternoon exercise training in metabolically compromised subjects enrolled in a 12-week exercise training program. Thirty-two adult males (58 ± 7 yrs) at risk for or diagnosed with type 2 diabetes performed 12 weeks of supervised exercise training either in the morning (8.00-10.00 a.m., N = 12) or in the afternoon (3.00-6.00 p.m., N = 20). Compared to participants who trained in the morning, participants who trained in the afternoon experienced superior beneficial effects of exercise training on peripheral insulin sensitivity (+5.2 ± 6.4 vs. -0.5 ± 5.4 µmol/min/kgFFM, p = .03), insulin-mediated suppression of adipose tissue lipolysis (-4.5 ± 13.7% vs. +5.9 ± 11%, p = .04), fasting plasma glucose levels (-0.3 ± 1.0 vs. +0.5 ± 0.8 mmol/l, p = .02), exercise performance (+0.40 ± 0.2 vs. +0.2 ± 0.1 W/kg, p = .05) and fat mass (-1.2 ± 1.3 vs. -0.2 ± 1.0 kg, p = .03). In addition, exercise training in the afternoon also tended to elicit superior effects on basal hepatic glucose output (p = .057). Our findings suggest that metabolically compromised subjects may reap more pronounced metabolic benefits from exercise training when this training is performed in the afternoon versus morning. CLINICALTRIALS.GOV ID: NCT01317576.

Gender differences in blood pressure and body composition in schoolchildren ascendants from Amerindian and European.

Background: In spite of there are a wide knowledge of the prevalence of hypertension in adult, there is poor information on schoolchildren of different ethnicity and gender.Aim: To compare the levels of blood pressure and other cardiometabolic risk factors for hypertension between schoolchildren of different gender and ethnicity.Material and methods: In a cross-sectional study, 540 schoolchildren (6-13 years) ascendants from a Chilean public school population were analysed by ethnicity and gender in four groups (Mapuches N = 55; European boys N = 199, and Mapuches N = 64, and European girls N = 222). The study included the measurement of cardiovascular (systolic and diastolic blood pressure) as main outcomes, as well as other cardiovascular (resting heart rate), body composition (body mass, BMI, waist circumference, fat mass, muscle mass), muscle strength (handgrip strength of dominant, non-dominant, and mean handgrip strength) as additional cardiometabolic outcomes.Results: The systolic blood pressure was significantly higher in Mapuches girls 126 ± 4 vs. their European counterparts 119 ± 3 mmHg, P < .002, as well as diastolic blood pressure, was higher in Mapuches girls 82 ± 5 vs. European girls 74 ± 3 mmHg, P < .0001. There were more 'prehypertensive' Mapuches girls 10 (15.6%) vs. European peers 22 (9.9%) at P < .0001, and the 'hypertension' was significantly more prevalent in Mapuches boys 19 (34.5%) vs. European peers 39 (19.4%) at P < .0001, as well as in Mapuches girls 16 (25%) vs. European peers 33 (14.9%) at P < .0001. The 'obesity' was less prevalent in Mapuches 10 (18.2%) vs. European boys 55 (27.4%) at P < .0001. The waist circumference was high in European 74 ± 4 vs. Mapuches 67 ± 6 cm, P < .012 in boys, although, waist circumference was high in Mapuches girls 75 ± 5 vs. European peers 71 ± 3 cm, P < .021. There were higher levels of muscle mass in Mapuches boys 19.5 ± 12 vs. European peers 17.1 ± 4 kg, P < .0001.Conclusion: Mapuches girls show higher levels of systolic and diastolic BP than European girls, Mapuches boys and girls are more hypertensive than European peers, but are less obese than European schoolchildren peers. These cardiometabolic differences that are more detrimental for endemic ethnic Latinoamerican groups are in need to be explored further.

Diurnal Regulation of Peripheral Glucose Metabolism: Potential Effects of Exercise Timing.

Diurnal oscillations in energy metabolism are linked to the activity of biological clocks and contribute to whole-body glucose homeostasis. Postprandially, skeletal muscle takes up approximately 80% of circulatory glucose and hence is a key organ in maintenance of glucose homeostasis. Dysregulation of molecular clock components in skeletal muscle disrupts whole-body glucose homeostasis. Next to light-dark cycles, nonphotic cues such as nutrient intake and physical activity are also potent cues to (re)set (dys)regulated clocks. Physical exercise is one of the most potent ways to improve myocellular insulin sensitivity. Given the role of the biological clock in glucose homeostasis and the power of exercise to improve insulin sensitivity, one can hypothesize that there might be an optimal time for exercise to maximally improve insulin sensitivity and glucose homeostasis. In this review, we aim to summarize the available information related to the interaction of diurnal rhythm, glucose homeostasis, and physical exercise as a nonphotic cue to correct dysregulation of human glucose metabolism.

Heart Rate During an Exercise Test and Acute High-intensity Interval Training in Type 2 Diabetes.

To describe and compare the acute heart rate changes during an incremental exercise test and high-intensity interval training (HIIT) in subjects of different glucose control. Seventy-five adults were allocated into three groups: Normoglycaemic (NG, n=32), Pre- (PreT2D, n=30) and Type 2 diabetic (T2D, n=13) subjects. Subjects performed an incremental cycling test to determine cardiorespiratory fitness (VO2max), maximum heart rate (HRmax) and HR recovery post maximal effort, as well as a HIIT cycling session. HR variations are reported as HR pre (HR-preINT), and post interval (HR-postINT), percentage of maximum HR (%HRmax), delta of HR increased (∆HRINT), and delta HR recovery after each interval (∆HRR). By groups, there was a significant difference for the %HRmax in 1st and 2nd, but not in intervals 3rd to 10th between Pre-T2D and T2D groups. There were significant differences for the %HRmax in 1st to 2nd intervals between Pre-T2D and T2D groups. Significant (P<0.05) differences at some intervals were found for ΔHRINT, and ΔHRR. These findings suggest that the HR during an incremental exercise test, and from a typical 10-intervals based HIIT protocol could be used as an intensity marker for individuals independent of their glycaemic control.

Efficient Bioconversion of High Concentration Phytosterol Microdispersion to 4-Androstene-3,17-Dione (AD) by Mycobacterium sp. B3805.

Low solubility of sterols in aqueous media limits efficient steroid production mediated by biocatalytic microorganisms such as Mycobacterium. Sterol emulsion technologies have been developed with low success rates, largely due to the complexity of generating stable and bioavailable particles. In this study, several aqueous dispersions of sterols in-water of different particle sizes were bioconverted to 4-androstene-3,17-dione (AD) in a solvent-free environment, using a classic microorganism Mycobacterium sp. B3805 as a model system. According to our results, the high concentration (20 g/L) phytosterol dispersions with the smallest particle size tested (370 nm) achieved up to 54% (7.4 g/L) AD production yield in 11 days. Moreover, the use of 0.1 biomass/sterols ratio in a complex bioconversion media containing yeast extract, and a 1:1 glucose/microdispersion ratio in the presence of the surfactant DK-Ester P-160 (HLB16), allowed homogenization and increased microdispersion stability, thus achieving the best results using emulsion technologies to date.

Entrenamiento interválico de alta intensidad contribuye a la normalización de la hipertensión arterial / Effects of high intensity interval training on blood pressure in hypertensive subjects

Background: Exercise training may reduce blood pressure. Aim: To determine the effects of a high intensity interval training (HIIT) exercise protocol on systolic and diastolic blood pressure in hypertensive subjects. Material and Methods: Eleven men and 27 women aged 46.4 ± 9.8 years were divided in two groups according to their blood pressure. Sixteen were classified as normotensive and 22 as hypertensive. All attended an exercise program with 3 sessions per week for a total of 24 sessions. Each session consisted of one minute of intense exercise performed on a stationary bike, followed by an inactive pause lasting two minutes. This cycle was repeated 10 times and it was thus called 1 * 2 * 10. Blood pressure, weight (kg) and body fat were assessed. Results: In the hypertensive group, there was a significant reduction in systolic blood pressure from 145.4 ± 9.0 to 118.3 ± 15.6 mm Hg (p < 0.05). No significant change was observed in diastolic blood pressure (84.9 ± 3.9 and 85.8 ± 17.6 mmHg. Thus, there was a mean reduction in systolic pressure of 27. 7 ± 18.9 mmHg. Therefore, 73% of patients achieved systolic pressures within normal range, without medication. Conclusions: The 1 * 2 * 10 exercise method is effective to improve and restore normal blood pressure in persons with hypertension in a period of two months and 24 sessions.

Production and Biotransformation of Phytosterol Microdispersions to Produce 4-Androstene-3,17-Dione.

The current state of knowledge regarding phytosterols biotransformation to produce the steroid intermediate 4-androstene-3,17-dione (AD) shows different technologies. However, the initial concentration of phytosterols in batch cultures is limited due to its low solubility in aqueous media, causing serious difficulties for scaling up because of the low mass transfer. In this chapter, we describe a fermentation method of a phytosterol microdispersion with Mycobacterium sp. B3805 in the context of an integral technology for AD production. The microdispersion generation is based on a patent application that claims the production of an aqueous phytosterol microdispersion with an average size particle of 370 nm, and high stability and solubility in water at high phytosterols concentrations (Harting et al., 2012/US0046254). Our results indicate that up to 20 g/L phytosterols can be biotransformed with this technology allowing a good dispersion and stability of reactants in the fermentation broth.

Rosa Mosqueta Oil Prevents Oxidative Stress and Inflammation through the Upregulation of PPAR-α and NRF2 in C57BL/6J Mice Fed a High-Fat Diet.

Background: Rosa mosqueta (RM) oil is characterized by high concentrations of antioxidants and α-linolenic acid (ALA; 18:3n-3). We have previously demonstrated in male C57BL/6J mice that RM decreases hepatic steatosis, a condition strongly associated with oxidative stress and inflammation.Objective: We studied the molecular mechanisms that underlie the role of RM in preventing high-fat diet (HFD)-induced oxidative stress and inflammation.Methods: Male C57BL/6J mice aged 28 d and weighing 12-14 g were divided into the following groups and fed for 12 wk: control diet (CD; 10% fat, 20% protein, and 70% carbohydrates); CD + RM (1.94 mg ALA ⋅ g body weight-1 ⋅ d-1 administered by oral gavage); HFD (60% fat, 20% protein, and 20% carbohydrates); and HFD + RM. General parameters (body weight, visceral fat, and histology); glucose metabolism [homeostasis model assessment and blood glucose area under the curve (AUC)]; oxidative stress [hepatic nuclear factor (erythroid-derived 2)-like-2 (NRF2) and heme oxygenase 1 (HO-1) concentrations]; and inflammation [hepatic peroxisome proliferator-activated receptor α (PPAR-α) and acyl-coenzyme A oxidase 1 (ACOX1) concentrations, blood tumor necrosis factor α (TNF-α) and interleukin 1ß (IL-1ß) concentrations, and Tnfa and Il1b mRNA expression in liver and visceral adipose tissue] were evaluated.Results: In the HFD + RM mice, the final body weight (24.8 ± 1.1 g) was 19% lower than in the HFD mice (30.6 ± 2.8 g) (P < 0.05). Visceral fat was 34% lower in the HFD + RM mice than in the HFD mice (P < 0.05). The blood glucose AUC was 29% lower and Tnfa and Il1b expression levels were 47% and 59% lower, respectively, in the HFD + RM mice than in the HFD mice (P < 0.05). HFD + RM mice had 40% less hepatic steatosis (P < 0.05) and lower upregulation of PPAR-α (33%), ACOX1 (50%), NRF2 (39%), and HO-1 (68%) protein concentrations than did the HFD mice (P < 0.05).Conclusions: Our findings suggest that RM supplementation prevents the obese phenotype observed in HFD-fed mice by downregulating inflammatory cytokine expression and secretion and stimulating hepatic antioxidant and fatty acid oxidation markers.

Effects of rosa mosqueta oil supplementation in lipogenic markers associated with prevention of liver steatosis.

Rosa mosqueta (RM) oil is rich in α-linolenic acid (ALA) - a precursor of eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), and it has a high antioxidant activity due to its abundant content of tocopherols. Additionally, it has been observed that RM oil administration prevents hepatic steatosis. Thus, the aim of this study was to demonstrate the antilipogenic mechanism related to RM oil administration in a high-fat diet (HFD) fed mice model by evaluating markers associated with the regulation of lipid droplet metabolism (PLIN2, PLIN5 and PPAR-γ), and proteins associated with lipogenesis (FAS and SREBP-1c). C57BL/6J mice were fed either a control diet or a HFD, with and without RM oil supplementation for 12 weeks. The results showed that RM oil supplementation decreases hepatic PLIN2 and PPAR-γ mRNA expression and SREBP-1c, FAS and PLIN2 protein levels, whereas we did not find changes in the level of PLIN5 among the groups. These results suggest that modulation of lipogenic markers could be one of the mechanisms, through which RM oil supplementation prevents the hepatic steatosis induced by HFD consumption in a mice model.

[Effects of high intensity interval training on blood pressure in hypertensive subjects]. / Entrenamiento interválico de alta intensidad contribuye a la normalización de la hipertensión arterial.

BACKGROUND: Exercise training may reduce blood pressure. AIM: To determine the effects of a high intensity interval training (HIIT) exercise protocol on systolic and diastolic blood pressure in hypertensive subjects. MATERIAL AND METHODS: Eleven men and 27 women aged 46.4 ± 9.8 years were divided in two groups according to their blood pressure. Sixteen were classified as normotensive and 22 as hypertensive. All attended an exercise program with 3 sessions per week for a total of 24 sessions. Each session consisted of one minute of intense exercise performed on a stationary bike, followed by an inactive pause lasting two minutes. This cycle was repeated 10 times and it was thus called 1 * 2 * 10. Blood pressure, weight (kg) and body fat were assessed. RESULTS: In the hypertensive group, there was a significant reduction in systolic blood pressure from 145.4 ± 9.0 to 118.3 ± 15.6 mm Hg (p < 0.05). No significant change was observed in diastolic blood pressure (84.9 ± 3.9 and 85.8 ± 17.6 mmHg. Thus, there was a mean reduction in systolic pressure of 27. 7 ± 18.9 mmHg. Therefore, 73% of patients achieved systolic pressures within normal range, without medication. CONCLUSIONS: The 1 * 2 * 10 exercise method is effective to improve and restore normal blood pressure in persons with hypertension in a period of two months and 24 sessions.

Changes in the heart rate recovery to endurance effort after high intensity interval, strength, and concurrent exercise training in patients with insulin resistance.

BACKGROUND: The aim of this study was to assess the effects of three exercise training programs in the adaptation of the heart rate recovery of patients with insulin resistance. METHODS: We studied 43 women with insulin resistance, which were assigned to three training groups: 1) high intensity interval training (HIT, age 39.0±10 years); 2) strength training (ST, age 33.9±9.4 years); 3) HIT+ST (MIXT, age 43.3±8.1 years); and 4) control group (CG, age 40.1±11 years). Heart rate was measured at rest (HRrest), during the 2-km-walking-test (UKKT) for mean (HRDE), and maximum (HRMDE) values, and during the recovery at one, two, and three minutes after the UKKT. Additionally, anthropometric measurements (body mass and body mass index) were assessed. RESULTS: HIT significantly decreased HRrest and HRDE (-4.5% and -2% respectively, P<0.05). MIXT training also decreased HRDE in -3% whilst both average and maximal HR during UKK were significantly increased in the control group HRDE (+2% and +3% respectively). Moreover, there were significant reductions in HR recovery at 1, 2 and 3 minutes after both HIT and MIXT training, whereas these values were increased in control group. CONCLUSIONS: Our findings suggest that HIT induces meaningful cardiovascular adaptations in patient with insulin resistance, reducing heart rate at rest, as well as during and after exercise, and that complementary strength training increases these adaptations.

Disminución de la grasa corporal mediante ejercicio físico intermitente de alta intensidad y consejería nutricional en sujetos con sobrepeso u obesidad / Effects of 12 sessions of high intensity intermittent training and nutrition counseling on body fat in obese and overweight participants

Background: The search of efficient exercise alternatives to treat obesity is worthwhile. Aim: To demonstrate the effect of high intensity intermittent exercise on body fat reduction in overweight and obese subjects. Material and Methods: A group of 65 overweight and obese adult subjects (25 men), aged 18-65 years, participated during 12 sessions in a high intensity physical exercise program, 3 days/week. Weight, height and body fat was measured before and after the intervention by bioimpedance. Each session consisted of 1 min stationary cycling exercise at high intensity, followed by 2 min inactive rest. This cycle was repeated 10 times, thus the method is called 1*2*10. Results: There was a significant reduction of body fat of -1.88 ± 2.8 and -3.44 ± 2.7 kg, in women and men, respectively (p < 0.05). Conclusions: The 1*2*10 training protocol lasting 12 weeks in association with nutrition counseling is effective in reducing body fat in overweight persons.

[Effects of 12 sessions of high intensity intermittent training and nutrition counseling on body fat in obese and overweight participants]. / Disminución de la grasa corporal mediante ejercicio físico intermitente de alta intensidad y consejería nutricional en sujetos con sobrepeso u obesidad.

BACKGROUND: The search of efficient exercise alternatives to treat obesity is worthwhile. AIM: To demonstrate the effect of high intensity intermittent exercise on body fat reduction in overweight and obese subjects. MATERIAL AND METHODS: A group of 65 overweight and obese adult subjects (25 men), aged 18-65 years, participated during 12 sessions in a high intensity physical exercise program, 3 days/week. Weight, height and body fat was measured before and after the intervention by bioimpedance. Each session consisted of 1 min stationary cycling exercise at high intensity, followed by 2 min inactive rest. This cycle was repeated 10 times, thus the method is called 1*2*10. RESULTS: There was a significant reduction of body fat of -1.88 ± 2.8 and -3.44 ± 2.7 kg, in women and men, respectively (p < 0.05). CONCLUSIONS: The 1*2*10 training protocol lasting 12 weeks in association with nutrition counseling is effective in reducing body fat in overweight persons.

[High intensity interval training improves glycemic control and aerobic capacity in glucose intolerant patients]. / Ejercicio físico interválico de alta intensidad mejora el control glicémico y la capacidad aeróbica en pacientes con intolerancia a la glucosa.

BACKGROUND: Proper exercise training modifies intra miocellular energy utilization, glucose transport and mitochondrial biogenesis. AIM: To determine the therapeutic effects of a high intensity intermittent training (HIIT) program on glucose homeostasis, physical fitness and body fat in glucose intolerant patients. PATIENTS AND METHODS: Eighteen patients with overweight or obesity and glucose intolerance were invited to participate in an exercise program consisting in three sessions per week for 3 months. Ten participants aged 35 ± 13 years who attended > 26 of the planned 36 sessions, were considered as adherent to exercise. The other eight participants aged 37 ± 17 years, who attended to a mean of 13 sessions, were considered as non-adherent. Both groups had similar body weight, body mass index, body fat, plasma glucose 2 h after an oral glucose load and maximal oxygen uptake. All these variables were measured at the end of exercise intervention. Each session consisted of 1 min exercise of cycling at maximal intensity until muscle fatigue followed by 2 min rest, repeated 10 times. RESULTS: Among adherent participants, twelve weeks of HIIT improved significantly maximal oxygen uptake (6.1 + 3.6 mL/kg/min or 24.6%), reduced 2 h post load blood glucose (-33.7 + 47.9 mg/dL or -12.5%) and body fat (-4.3 + 5.6 kg). No significant changes were observed in the non-adherent group. CONCLUSIONS: HIIT exercise reduces blood glucose after an oral load in glucose intolerant patients.

Ejercicio físico interválico de alta intensidad mejora el control glicémico y la capacidad aeróbica en pacientes con intolerancia a la glucosa / High intensity interval training improves glycemic control and aerobic capacity in glucose intolerant patients

Background: Proper exercise training modifies intra miocellular energy utilization, glucose transport and mitochondrial biogenesis. Aim: To determine the therapeutic effects of a high intensity intermittent training (HIIT) program on glucose homeostasis, physical fitness and body fat in glucose intolerant patients. Patients and Methods: Eighteen patients with overweight or obesity and glucose intolerance were invited to participate in an exercise program consisting in three sessions per week for 3 months. Ten participants aged 35 ± 13 years who attended > 26 of the planned 36 sessions, were considered as adherent to exercise. The other eight participants aged 37 ± 17 years, who attended to a mean of 13 sessions, were considered as non-adherent. Both groups had similar body weight, body mass index, body fat, plasma glucose 2 h after an oral glucose load and maximal oxygen uptake. All these variables were measured at the end of exercise intervention. Each session consisted of 1 min exercise of cycling at maximal intensity until muscle fatigue followed by 2 min rest, repeated 10 times. Results: Among adherent participants, twelve weeks of HIIT improved signifcantly maximal oxygen uptake (6.1 + 3.6 mL/kg/min or 24.6%), reduced 2 h post load blood glucose (-33.7 + 47.9 mg/dL or -12.5%) and body fat (-4.3 + 5.6 kg). No signifcant changes were observed in the non-adherent group. Conclusions: HIIT exercise reduces blood glucose after an oral load in glucose intolerant patients.

Hypolithic cyanobacteria supported mainly by fog in the coastal range of the Atacama Desert.

The Atacama Desert is one of the driest places on Earth, with an arid core highly adverse to the development of hypolithic cyanobacteria. Previous work has shown that when rain levels fall below ~1 mm per year, colonization of suitable quartz stones falls to virtually zero. Here, we report that along the coast in these arid regions, complex associations of cyanobacteria, archaea, and heterotrophic bacteria inhabit the undersides of translucent quartz stones. Colonization rates in these areas, which receive virtually no rain but mainly fog, are significantly higher than those reported inland in the hyperarid zone at the same latitude. Here, hypolithic colonization rates can be up to 80%, with all quartz rocks over 20 g being colonized. This finding strongly suggests that hypolithic microbial communities thriving in the seaward face of the Coastal Range can survive with fog as the main regular source of moisture. A model is advanced where the development of the hypolithic communities under quartz stones relies on a positive feedback between fog availability and the higher thermal conductivity of the quartz rocks, which results in lower daytime temperatures at the quartz-soil interface microenvironment.

Effect of manganese on the secretion of manganese-peroxidase by the basidiomycete Ceriporiopsis subvermispora.

The ligninolytic machinery of the widely used model fungus Ceriporiopsis subvermispora includes the enzymes manganese-peroxidase (MnP) and laccase (Lcs). In this work the effect of Mn(II) on the secretion of MnP was studied. Cultures grown in the absence of Mn(II) showed high levels of mnp transcripts. However, almost no MnP enzyme was detected in the extracellular medium, either by enzymatic activity assays or Western blot hybridizations. In the corresponding mycelia, immuno-electron microscopy experiments showed high levels of MnP enzyme within intracellular compartments. These results suggest that in addition to its well-known effect on transcription regulation of mnp genes, manganese influences secretion of MnP to the extracellular medium. Experiments carried out in the presence of cycloheximide confirmed that the metal is required to secrete MnP already synthesized and retained within the cell.

Hydroquinone and HO differentially affect the ultrastructure and expression of ligninolytic genes in the basidiomycete Ceriporiopsis subvermispora.

The biodegradation of lignin is a highly oxidative process in which various oxidases and peroxidases play a major role. During lignin decay, the generation of aromatic compounds and reactive oxygen species leads to oxidative stress. In this work, the effect of the oxidative compounds H(2)O(2) and hydroquinone in the ligninolytic fungus Ceriporiopsis subvermispora was studied, both at the ultrastructural and at the transcriptional level. Transmission electron microscopy revealed the presence of microvesicles and extensive cytoplasm degeneration after incubation with hydroquinone, but not with H(2)O(2). Studies of the intracellular redox state of the fungus showed that hydroquinone causes a transient decrease in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and an increase in the glutathione-S-transferase mRNA levels. These results suggest that hydroquinone produces oxidative stress in this microorganism. On the other hand, it was observed that hydroquinone, but not H(2)O(2), affects Mn-dependent peroxide and laccase transcripts levels. We propose that the mechanism by which the fungus reacts against oxidative stress contributes to its selectivity toward lignin during wood decay.