MultiClassMetabo: A Superior Classification Model Constructed Using Metabolic Markers in Multiclass Metabolomics.

Multiclass metabolomics has become a popular technique for revealing the mechanisms underlying certain physiological processes, different tumor types, or different therapeutic responses. In multiclass metabolomics, it is highly important to uncover the underlying biological information on biosamples by identifying the metabolic markers with the most associations and classifying the different sample classes. The classification problem of multiclass metabolomics is more difficult than that of the binary problem. To date, various methods exist for constructing classification models and identifying metabolic markers consisting of well-established techniques and newly emerging machine learning algorithms. However, how to construct a superior classification model using these methods remains unclear for a given multiclass metabolomic data set. Herein, MultiClassMetabo has been developed for constructing a superior classification model using metabolic markers identified in multiclass metabolomics. MultiClassMetabo can enable online services, including (a) identifying metabolic markers by marker identification methods, (b) constructing classification models by classification methods, and (c) performing a comprehensive assessment from multiple perspectives to construct a superior classification model for multiclass metabolomics. In summary, MultiClassMetabo is distinguished for its capability to construct a superior classification model using the most appropriate method through a comprehensive assessment, which makes it an important complement to other available tools in multiclass metabolomics. MultiClassMetabo can be accessed at http://idrblab.cn/multiclassmetabo/.

Phosphorus Addition Reduces Seedling Growth and Survival for the Arbuscular Mycorrhizal Tree Cinnamomum camphora (Lauraceae) and Ectomycorrhizal Tree Castanopsis sclerophylla (Fagaceae) in Fragmented Forests in Eastern China.

Global changes in nutrient deposition rates and habitat fragmentation are likely to have profound effects on plant communities, particularly in the nutrient-limited systems of the tropics and subtropics. However, it remains unclear how increased phosphorus (P) supply affects seedling growth in P-deficient subtropical fragmented forests. To explore this, we applied P to 11 islands in a subtropical Chinese archipelago and examined the results in combination with a contemporary greenhouse experiment to test the influence of P addition on seedling growth and survival. We measured the growth (i.e., base area) and mortality rate of seedlings for one arbuscular mycorrhizal (AM) and one ectomycorrhizal (EcM) tree species separately and calculated their relative growth rate and mortality when compared with P addition and control treatment on each island. We also measured three functional traits and the biomass of seedlings in the greenhouse experiment. Results showed that P addition significantly increased the mortality of AM and EcM seedlings and reduced the growth rate of EcM seedlings. The relative growth rate of AM seedlings, but not EcM seedlings, significantly decreased as the island area decreased, suggesting that P addition could promote the relative growth rate of AM seedlings on larger islands. The greenhouse experiment showed that P addition could reduce the specific root length of AM and EcM seedlings and reduce the aboveground and total biomass of seedlings, indicating that P addition may affect the resource acquisition of seedlings, thereby affecting their survival and growth. Our study reveals the synergistic influence of habitat fragmentation and P deposition, which may affect the regeneration of forest communities and biodiversity maintenance in fragmented habitats.

Does ovulation affect performance in tennis players?

BACKGROUND: Scientific data on the performance of collegiate female tennis players during the menstrual phases are scarce. TRIAL DESIGN: Double-blind, counter-balanced, crossover trials were conducted to examine whether tennis performance was affected during menstruation, with and without dehydroepiandrosterone sulfate (DHEA-S) supplementation. METHODS: Ten Division 1 collegiate tennis players (aged 18-22 years) were evenly assigned into placebo-supplemented and DHEA-supplemented (25 mg/day) trials. Treatments were exchanged among the participants after a 28-day washout. Tennis serve performance was assessed on the first day of menstrual bleeding (day 0/28) and on days 7, 14 and 21. RESULTS: Mood state was unaltered during the menstrual cycles in both trials. The lowest tennis serve performance score (speed times accuracy) occurred on day 14 (P=0.06 vs day 0; P=0.01 vs day 21) in both placebo and DHEA trials. Decreased performance on day 14 was explained by decreased accuracy (P=0.03 vs day 0/28; P=0.01 vs day 21), but not velocity itself. Isometric hip strength, but not quadriceps strength, was moderately lower on day 14 (P=0.08). Increasing plasma DHEA-S (by ~65%) during the DHEA-supplemented trial had no effects on mood state, sleep quality or tennis serve performance. CONCLUSION: We have shown that menses does not affect serve performance of collegiate tennis players. However, the observed decrement in the accuracy of serve speed near ovulation warrants further investigation.

Altitude training improves glycemic control.

UNLABELLED: Under altitude hypoxia condition, energy reliance on anaerobic glycolysis increases to compensate the shortfall caused by reduced fatty acid oxidation. Short-term moderate altitude exposure plus endurance physical activity has been found to improve glucose tolerance (not fasting glucose) in humans, which is associated with the improvement in the whole-body insulin sensitivity. However, most of people cannot accommodate high altitude exposure above 4500 M due to acute mountain sickness and insulin resistance. There is a wide variation among individuals in response to the altitude challenge. In particular, the improvement in glucose tolerance and insulin sensitivity by prolonged altitude hiking activity was not apparent in those individuals with low baseline dehydroepiandrosterone sulfate (DHEA-S) concentration. In rats, exercise training recovery under prolonged hypoxia exposure (14-15% oxygen, 8 h per day for 6 weeks) can also improve insulin sensitivity, secondary to an effective suppression of adiposity. After prolonged hypoxia training, obese abnormality in upregulated baseline levels of AMP-activated protein kinase (AMPK) and AS160 phosphorylation in skeletal muscle can be reversed. In humans, moderate hypoxia increases postprandial blood distribution towards skeletal muscle during a training recovery. This physiological response plays a role in the redistribution of fuel storage among important energy storage sites and may explain its potent effect on the favorable change in body composition. CONCLUSION: Altitude training can exert strong impact on our metabolic system, and has the potential to be designed as a non-pharmacological or recreational intervention regimen for correcting metabolic syndromes.

Dehydroepiandrosterone sulfate linked to physiologic response against hot spring immersion.

The steroid dehydroepiandrosterone sulfate (DHEA-S) is associated with longevity and adaptation against external stress in humans. The aim of the study was to investigate the acute effect of a 30-min hot spring immersion at 41 degrees C on insulin resistance measures of 16 male subjects, in relation to DHEA-S level. To elucidate the role of DHEA-S in the coping against the heat stress, all subjects were evenly divided into lower and upper halves according to their baseline DHEA-S concentrations. The levels of glucose, insulin, blood pressure, and stress hormones (growth hormone, testosterone, and cortisol) in both groups were compared before and after hot spring immersion. The result shows that hot spring immersion significantly increased heart rate and reduced diastolic blood pressure, both of which were paralleled with a drop of DHEA-S concentration. Homeostasis model assessment for insulin resistance (HOMA-IR) and area under curve of glucose (GAUC) of oral glucose tolerance test were significantly increased by the hot spring immersion only in the Low DHEA-S group. Likewise, hot spring immersion caused an opposing effect on cortisol changes for the Low and High DHEA-S groups (+95% vs. -33%, p<0.05), respectively. In conclusion, hot spring bathing induced insulin resistance confined only to those Low DHEA-S individuals. This response may be associated with a stress response such as increased cortisol levels.

The role of DHEA-S in the mood adjustment against negative competition outcome in golfers.

Several lines of evidence suggest that dehydroepiandrosterone sulphate (DHEA-S) is invariably consumed following different types of acute stress, implicating its role in stress coping and recovery. The role of DHEA-S in the mood adjustment against negative outcome for athletic competition has not previously been investigated. In the current study, 14 elite golfers participating in a major national golf tournament were subsequently divided into two groups according to their competition outcomes: made the cut (n=8) and failed to make the cut (n 8). The Profile of Mood States (POMS) inventory and plasma concentrations of DHEA-S and cortisol were measured 1 day before the beginning of competition (baseline) and 1, 3, and 5 days after the players' final competition, in the morning (08.00-08.30 h) under fasted conditions. Results showed that the total mood disturbance scores and DHEA-S were not changed for the group that made the cut throughout the entire observation period. DHEA-S concentration for the group that failed to make the cut fell significantly below baseline values on day 1 and remained lower for 5 days. The Depression subscale of the POMS for the group that failed to make the cut was increased only on day 1 post-competition, reflecting a situational reaction to the event. Cortisol concentration for the group that made the cut fell significantly below baseline values on day 1 only after competition and no change was observed for the group that failed to make the cut. In conclusion, although the overall mood state post-competition was well-maintained for those golfers who had a negative competition outcome, plasma DHEA-S concentration was reduced for 5 days, suggesting that it has a role in the coping mechanism against psychological challenge.

Suppression of age-dependent increase in insulinemia in early middle-aged females with exercise habit.

Circulating insulin concentration has been suggested as a biomarker for human longevity. The goal of the study was to determine the insulin levels under a glucose-challenged condition for the sedentary and physical active females in early middle age. We measured serum insulin levels for following groups: young sedentary (Y-SED, age 19.7 +/- 0.2 years), middle-aged sedentary (M-SED, age 42.3 +/- 3.1 years), young physically active (Y-EX, age 20.7 +/- 0.5 years), and middle-aged physically active (M-EX, age 40.3 +/- 2.8 years). Oral glucose tolerance test (OGTT) and insulin measurement were performed under overnight fasted condition. Triglyceride, cholesterol, body mass index (BMI), and waist-to-hip ratio (WHR) were also determined in all subjects. While fasted glucose and insulin levels were not different among 4 groups, glucose and insulin levels under OGTT were greater in the M-SED group than those in the Y-SED group. The M-EX subjects exhibited lower insulin levels on OGTT, as compared to the M-SED group, and were similar to the level of Y-SED. BMI and WHR of the M-SED group were comparable to those of the M-EX group. Triglyceride and cholesterol levels were highly associated with age and WHR but not the level of physical activity. The current study found a substantially greater insulin response on OGTT in the healthy sedentary females aged approximately 40, as compared to those in the young sedentary and the middle-aged physically active females, independent of weight status. The result of the study also suggests that accumulating 150 min of weekly exercise is sufficient to counteract the adverse effect of age on insulin sensitivity.

The role of dehydroepiandrosterone levels on physiologic acclimatization to chronic mountaineering activity.

Previous studies have reported that glucose tolerance can be improved by short-term altitude living and activity. However, not all literature agrees that insulin sensitivity is increased at altitude. The present study investigated the effect of a 25-day mountaineering activity on glucose tolerance and its relation to serum levels of dehydroepiandrosterone-sulfate (DHEA-S) and tumor necrosis factor-alpha (TNF-alpha) in 12 male subjects. On day 3 at altitude, we found that serum DHEAS was reduced in the subjects with initially greater DHEA-S value, whereas the subjects with initially lower DHEA-S remained unchanged. To further elucidate the role of DHEA-S in acclimatization to mountaineering activity, all subjects were then divided into lower and upper halves according to their sea-level DHEA-S concentrations: low DHEA-S (n = 6) and high DHEA-S groups (n = 6). Glucose tolerance, insulin level, and the normal physiologic responses to altitude exposure, including hematocrit, hemoglobin, erythropoietin (EPO), and cortisol were measured. We found that glucose and insulin concentrations on an oral glucose tolerance test were significantly lowered by the mountaineering activity only in the high DHEA-S group. Similarly, hematocrit and hemoglobin concentration in altitude were increased only in the high DHEA-S group. In contrast, the low DHEA-S subjects exhibited an EPO value at sea level and altitude greater than the high DHEA-S group, suggesting an EPO resistance. The findings of the study imply that DHEA-S is essential for physiologic acclimatization to mountaineering challenge.

Effect of resistance exercise on dehydroepiandrosterone sulfate concentrations during a 72-h recovery: relation to glucose tolerance and insulin response.

Serum dehydroepiandrosterone sulfate (DHEA-S) concentration is known to be associated with the whole-body insulin sensitivity. The main purpose of the study was to investigate the effect of resistance exercise on DHEA-S concentration during a 72 h post-exercise recovery, and its relation to glucose tolerance and insulin sensitivity. Morning fasted serum samples was obtained from 19 male volunteers (aged 21.1+/-0.4 years) 24 h before the onset of exercise and 24 h, 48 h, and 72 h following exercise for measurements of DHEA-S, cortisol, and TNF-alpha. Oral glucose tolerance test (OGTT) and insulin response were determined 24 h before and 48 h after exercise. We found that resistance exercise causes a delayed suppression in serum DHEA-S levels during recovery (48 h and 72 h). This exercise challenge did not affect glucose tolerance, but insulin response during OGTT was significantly elevated. The increased insulin level was not associated with serum levels of cortisol and TNF-alpha. In conclusion, the present study found that resistance exercise has a DHEA-S lowering effect that persisted for 72 h. This change could be related to the elevated insulin concentrations during OGTT.

Validity of the 3 min step test in moderate altitude: environmental temperature as a confounder.

The 3 min step test is a widely used method to evaluate physical fitness, but whether this method is valid when performed at altitude is unknown. The purpose of this study was to examine the effect of altitude on the fitness score of the 3 min step test, and the role of ambient temperature in this effect. In study I, 11 healthy volunteers (aged 18.1 +/- 1.1 years) performed a 3 min step test at sea level and at altitude (1950 m). Plasma lactate and stress hormones, as indicators of metabolic stress, were measured before and after the test. To determine the role of ambient temperature, we performed study II at sea level with the same step test simulating the altitude temperature condition (24 degrees C at high altitude versus 32 degrees C at sea level) with 23 subjects (aged 20.4 +/- 0.4 y). In study I, plasma lactate of the subjects was elevated during the step test at sea level and to a greater extent at high altitude. Plasma cortisol and testosterone levels were elevated only at high altitude. However, the heart rate (HR) recovery after the step test was faster at high altitude than at sea level, producing a better physical fitness index. Furthermore, in study II, we demonstrated that the subjects who performed the 3 min step test at 24 degrees C exhibited faster HR recovery than at 32 degrees C. The current study therefore suggests that environmental conditions leading to temperature variation have strong confounding effects on the fitness score of the 3 min step test.

Acute effect of exercise-hypoxia challenge on GLUT4 protein expression in rat cardiac muscle.

Altitude training is a frequently used method for enhancing endurance performance in athletes. But its acute effect on carbohydrate metabolism in cardiac muscle is unknown. In this study, we determined the acute effect of an exercise-hypoxia challenge on glycogen storage and GLUT4 protein expression in heart muscle. Sixteen male Sprague-Dawley rats were assigned to one of two groups: control (CTRL) and exercise-hypoxia (EX+HY). The exercise protocol consisted of swimming for 180 min twice, with a 45-min rest interval. Five hours after the exercise, the EX+HY rats were exposed to a 14% O(2) systemic hypoxia under normobaric condition for 12 h. After this hypoxia exposure, the EX+HY and control rats were given glucose orally (1 g/kg body weight) with stomach tube and recovered under normal condition for 16 h. Ventricular portion of the heart was used to determine the levels of glycogen, GLUT4 mRNA, and GLUT4 protein after recovery. We found that myocardial glycogen level was lowered by the exercise-hypoxia challenge (51% below control, p < 0.05), while GLUT4 mRNA was dramatically elevated (approximately 400% of the control level, p < 0.05). The acute exercise-hypoxia treatment did not affect GLUT1 protein level in the same tissue. The novel finding of the study was that the exercise-hypoxia treatment significantly induced GLUT4 gene expression in the cardiac muscle. This acute response appears to be associated with a sustained glycogen depletion of the muscle.

Characteristics of glycemic control in elite power and endurance athletes.

A previous study has shown that former elite power athletes exhibited significantly greater relative risk in diabetes than that of former elite endurance athletes. It is unknown whether insulin sensitivity in elite young healthy power athletes is lower than that in elite young endurance athletes. This study includes two parts, part I and part II. In the part I of this study, an oral glucose tolerance test was performed in all of the elite juvenile track athlete subjects, specializing either in short-distance racing (jSD, N = 13, aged 12.5 +/- 0.37 years) or in long-distance racing (jLD, N = 13, aged 12.6 +/- 0.42 years). In the part II of this study, we recruited elite adult swimmers and divided them into two groups according to their specialty in swimming race distance: long-distance (aLD, N = 10, age 20.3 +/- 1.32) and short-distance groups (aSD, N = 10, age 20.2 +/- 1.31). Insulin sensitivity was significantly lower in the jSD group than that in the jLD group, as indicated by the area under the curves of insulin and glucose following a 75-g oral glucose load. Fasting plasma LDL-C and total cholesterol levels in the jSD group were significantly greater than those in the jLD group. The result of the part II of this study, similar to the result of the part I, shows that insulin sensitivity in aSD swimmers was significantly lower than that in aLD swimmers. LDL-C, total cholesterol, and triglyceride levels were also found higher in aSD swimmers than in those of aLD swimmers. These new findings implicate that the genetic makeup associated with exceptional power or endurance performance of elite athletes could also reflect on their metabolic characteristics; elite power athletes appear to be more insulin resistant than elite endurance athletes.