Karyological, biochemical, and physiological aspects of Callophysus macropterus (Siluriformes, Pimelodidae) from the Solimões and Negro Rivers (Central Amazon)

Karyological characteristics, i.e., diploid number, chromosome morphology and nucleolus organizer regions (NORs), biochemical characteristics, i.e., electrophoretic analysis of blood hemoglobin and the tissue enzymes lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), and phosphoglucose isomerase (PGI), and physiological characteristics, i.e., relative concentration of hemoglobin and intraerythrocytic concentrations of organic phosphates were analyzed for the species Callophysus macropterus collected from Marchantaria Island (white water system - Solimões River) and Anavilhanas Archipelago (black water system - Negro River). Karyological and biochemical data did not reveal significant differences between specimens collected at the two sites. However, the relative distribution of hemoglobin bands I and III (I = 16.33 ± 1.05 and III = 37.20 ± 1.32 for Marchantaria specimens and I = 6.33 ± 1.32 and III = 48.05 ± 1.55 for Anavilhanas specimens) and levels of intraerythrocytic GTP (1.32 ± 0.16 and 2.76 ± 0.18 for Marchantaria and Anavilhanas specimens, respectively), but not ATP or total phosphate, were significantly different, indicating a physiological adaptation to the environmental conditions of these habitats. It is suggested that C. macropterus specimens from the two collecting sites belong to a single population, and that they adjusted some physiological characteristics to adapt to local environmental conditions.

Chemical and physiological aspects of isomers of conjugated fatty acids

Conjugated fatty acid (CFA) is the general term to describe the positional and geometric isomers of polyunsaturated fatty acids with conjugated double bonds. The CFAs of linoleic acid (CLAs) are found naturally in foods derived from ruminant animals, meat, or dairy products. The CFAs of α-linolenic acid (CLNAs) are found exclusively in various types of seed oils of plants. There are many investigations to assess the effects to health from CFAs consumption, which have been associated with physiological processes that are involved with non transmissible chronic diseases such as cancer, atherosclerosis, inflammation, and obesity. Conclusive studies about the CFAs effects in the body are still scarce and further research about their participation in physiological processes are necessary. This review aimed to discuss the influence of conjugated fatty acids on physiological processes in animal organism.

Eco-physiological aspects of melaleuca seed germination

The invasive behavior of melaleuca (Melaleuca quinquenervia) plants in wetlands is due to its aggressive regeneration strategy, which is based on its seeds germination performance. Understanding of the eco-physiological aspects of the seed germination in melaleuca plants may significantly contribute for the development of management strategies. The objective of this research was to learn how the germination of M. quinquenervia seeds are affected by light and temperature. Melaleuca seeds were placed on filter paper moistened with 12 ml of distilled water at temperatures between 10 and 45°C. Germination was evaluated in dark and light conditions. Seed germination, first count of seed germination (seven days), germination speed index and germination mean time were determined up to 40 days after seeding, when germination had ceased in most of the treatments. After that period, the seeds were transferred to conditions of 30°C and light, which was found to be ideal in the previous phase. Seed germination was daily evaluated up to 63 days when it was again observed no longer to occur. The treatment repetitions were distributed in the growth-chamber according to a completely randomized design in a factorial scheme (eight temperatures x two light conditions) and four repetitions. The data were submitted to analysis of variance with the F test and the means were adjusted to polynomial and non linear regression models. The highest seed germination performance was observed to take place under conditions of 27.3°C with light. The temperatures of 35 and 40°C in the dark induced thermal inhibition of seed germination. The temperature of 45°C was lethal to the seeds.

Human skeletal muscle pyruvate dehydrogenase phosphatase activity and expression : the effect of aerobic capacity

Activation of pyruvate dehydrogenase (PDH), which converts pyruvate into acetyl-CoA, is accomplished by a pair of specific phosphatases (PDP 1 & 2). A cross-sectional study investigating the effect of aerobic capacity on PDP activity and expression found that: 1) PDP activity and PDP! protein expression were positively correlated with most aerobic capacity measures in males (n=lS), but not females (n=12); 2) only males showed a positive correlation between PDP activity and PDPl protein expression (r=0.47; p=O.05), indicating that the increase in PDP activity in males is largely explained by increased PDPl protein expression, but that females rely on another level for PDP activity regulation; and 3) PDP} and Ela protein expression increase in unison when expressed relative to the E2 core. These data suggest that with increased aerobic capacity there is an increased capacity for carbohydrate oxidation through PDH, via El a, and an increased ability to activate PDH, via PDP, when exercising maximally.

Comparison Among Aerobic Exercise and Other Types of Interventions to Treat Depression: A Systematic Review

Depression is a common and disabling disease that affects over 100 million people worldwide and can have a significant impact on physical and mental health, reducing their quality of life. Thus, the aim of this article was to provide information on research results and key chains related to the therapeutic effects of chronic aerobic exercise compared with other types of interventions to treat depression, which may become a useful clinical application in a near future. Researches have shown the effectiveness of alternative treatments, such as physical exercise, minimizing high financial costs and minimizing side effects. In this review, the data analyzed allows us to claim that alternative therapies, such as exercise, are effective on controlling and reducing symptoms. 69.3% of the studies that investigated the antidepressant effects of exercise on depressive were significant, and the other 30.7% of the studies improved only in general physiological aspects, such as increased oxygen uptake, increased use of blood glucose and decreased body fat percentage, with no improvement on symptoms of depression. From the sample analyzed, 71.4% was composed of women, and regarding the severity of symptoms, 85% had mild to moderate depression and only 15% had moderate to severe depression. However, there is still disagreement regarding the effect of exercise compared to the use of antidepressants in symptomatology and cognitive function in depression, this suggests that there is no consensus on the correct intensity of aerobic exercise as to achieve the best dose-response, with intensities high to moderate or moderate to mild.

Exercise and Mood: Exploring the Role of Exercise in Regulating Stress Reactivity in Bipolar Disorder

Bipolar Disorder (BD) is a recurrent and debilitating psychological disorder characterized by a chronic dysregulation of mood with fluctuations between extremely low (e.g., depression) and extremely elevated mood states (e.g., mania), and ranks as the 6th leading cause of disability in the world. Although research has consistently shown that exercise may have antidepressant and stress-attenuating benefits in other psychiatric illnesses (e.g., depression, anxiety), these benefits have not been directly investigated for BD. The current study represents the first known investigation to examine this relationship. Single-participant designs, with crossover and interaction treatment components (i.e., A/B/A/B/A, A/C/A/C/A, A/B/A/C/A, or A/C/A/B/A) were utilized to investigate the impact of participation in a prescribed regimen of exercise (EP) versus standard behavioral activation (SBA; i.e., non-exercise activity) has on stress perception and reactivity, and mood stability in a sample of individuals with BD. Individuals completed four total weeks of treatment, and psychophysiological measures of reactivity were recorded during a laboratory stress task (i.e., backward counting task) prior to and following each two-week intervention phase. No appreciable differences were found between levels of exercise participation between treatment groups. Interestingly, symptoms of depressed mood (BDI-II scores) decreased at similar rates following 4 weeks of treatment for all participants. BDI-II decreases were found to be most correlated with elective exercise participation, although this relationship was not significant. Regarding stress reactivity, elective participation in mild to moderate intensity exercise was found to reduce an individual’s perception of stress reactivity to an acute stressor, while participation in a prescribed program of exercise was more effective in reducing physiological response to the same task. Utilizing multiple forms of behavioral activation simultaneously was found to be most effective in decreasing perception of stress reactivity, and may also result in a positive change in the use of adaptive versus maladaptive coping strategies. Participation in a 4-week program of exercise appeared to provide the most benefit, consistent with exercise habituation theories. Overall, current findings provide preliminary support for the prophylactic benefits of including a prescribed and monitored program of exercise as an adjunct treatment for individuals with BD. Larger scale research is needed to more clearly determine the impact of exercise on stress reactivity and mood episode relapse in individuals with BD.

Genetic Aspects Of Athletic Performance: The African Runners Phenomenon.

The current dominance of African runners in long-distance running is an intriguing phenomenon that highlights the close relationship between genetics and physical performance. Many factors in the interesting interaction between genotype and phenotype (eg, high cardiorespiratory fitness, higher hemoglobin concentration, good metabolic efficiency, muscle fiber composition, enzyme profile, diet, altitude training, and psychological aspects) have been proposed in the attempt to explain the extraordinary success of these runners. Increasing evidence shows that genetics may be a determining factor in physical and athletic performance. But, could this also be true for African long-distance runners? Based on this question, this brief review proposed the role of genetic factors (mitochondrial deoxyribonucleic acid, the Y chromosome, and the angiotensin-converting enzyme and the alpha-actinin-3 genes) in the amazing athletic performance observed in African runners, especially the Kenyans and Ethiopians, despite their environmental constraints.

The influence of recreational ball hockey play on cardiovascular risk factors in sedentary males

Introduction: The prevalence of coronary artery disease (CAD) is ever increasing in western industrialized societies. An individuals overall risk for CAD may be quantified by integrating a number of factors including, but not limited to, cardiorespiratory fitness, body composition, blood lipid profile and blood pressure. It might be expected that interventions aimed at improving any or all of these independent factors might improve an individual 's overall risk. To this end, the influence of standard endurance type exercise on cardiorespiratory fitness, body composition, blood lipids and blood pressure, and by extension the reduction of coronary risk factors, is well documented. On the other hand, interval training (IT) has been shown to provide an extremely powerful stimulus for improving indices of cardiorespiratory function but the influence of this training type on coronary risk factors is unknown. Moreover, the vast majority of studies investigating the effects of IT on fitness have used laboratory type training protocols. As a result of this, the influence of participation in interval-type recreational sports on cardiorespiratory fitness and coronary risk factors is unknown. Aims: The aim of the present study was to evaluate the effectiveness of recreational ball hockey, a sport associated with interval-type activity patterns, on indices of aerobic function and coronary risk factors in sedentary men in the approximate age range of 30 - 60 years. Individual risk factors were compiled into an overall coronary risk factor score using the Framingham Point Scale (FPS). Methods: Twenty-four sedentary males (age range 30 - 60) participated in the study. Subject activity level was assessed apriori using questionnaire responses. All subjects (experimental and control) were assessed to have been inactive and sedentary prior to participation in the study. The experimental group (43 ± 3 years; 90 ± 3 kg) (n = 11) participated in one season of recreational ball hockey (our surrogate for IT). Member of this group played a total of 16 games during an 11 week span. During this time, the control group (43 ± 2 years; 89 ± 2 kg) (n = 11) performed no training and continued with their sedentary lifestyle. Prior to and following the ball hockey season, experimental and control subjects were tested for the following variables: 1) cardiorespiratory fitness (as V02 Max) 2) blood lipid profile 3) body composition 5) waist to hip ratio 6) blood glucose levels and 7) blood pressure. Subject V02 Max was assessed using the Rockport submaximal walking test on an indoor track. To assess body composition we determined body mass ratio (BMI), % body fat, % lean body mass and waist to hip ratio. The blood lipid profile included high density lipoprotein, low density lipoprotein and total cholesterol levels; in addition, the ratio of total cholesterol to high density was calculated. Blood triglycerides were also assessed. All data were analyzed using independent t - tests and all data are expressed as mean ± standard error. Statistical significance was accepted at p :S 0.05. Results: Pre-test values for all variables were similar between the experimental and control group. Moreover, although the intervention used in this study was associated with changes in some variables for subjects in the experimental group, subjects in the control group did not exhibit any changes over the same time period. BODY COMPOSITION: The % body fat of experimental subjects decreased by 4.6 ± 0.5%, from 28.1 ± 2.6 to 26.9 ± 2.5 % while that of the control group was unchanged at 22.7 ± 1.4 and 22.2 ± 1.3 %. However, lean body mass of experimental and control subjects did not change at 64.3 ± 1.3 versus 66.1 ± 1.3 kg and 65.5 ± 0.8 versus 64.7 ± 0.8 kg, respectively. In terms of body mass index and waist to hip ratio, neither the experimental nor the control group showed any significant change. Respective values for the waist to hip ratio and body mass index (pre and post) were as follows: 1 ± 0.1 vs 0.9 ± 0.1 (experimental) and 0.9 ± 0.1 versus 0.9 ± 0.1 (controls) while for BMI they were 29 ± 1.4 versus 29 ± 1.2 (experimental) and 26 ± 0.7 vs. 26 ± 0.7 (controls). CARDIORESPIRATORY FITNESS: In the experimental group, predicted values for absolute V02 Max increased by 10 ± 3% (i.e. 3.3 ± 0.1 to 3.6 ± 0.1 liters min -1 while that of control subjects did not change (3.4 ± 0.2 and 3.4 ± 0.2 liters min-I). In terms of relative values for V02 Max, the experimental group increased by 11 ± 2% (37 ± 1.4 to 41 ± 1.4 ml kg-l min-I) while that of control subjects did not change (41 ± 1.4 and 40 ± 1.4 ml kg-l min-I). BLOOD LIPIDS: Compared to pre-test values, post-test values for HDL were decreased by 14 ± 5 % in the experiment group (from 52.4 ± 4.4 to 45.2 ± 4.3 mg dl-l) while HDL data for the control group was unchanged (49.7 ± 3.6 and 48.3 ± 4.1 mg dl-l, respectively. On the other hand, LDL levels did not change for either the experimental or control group (110.2 ± 10.4 versus 112.3 ± 7.1 mg dl-1 and 106.1 ± 11.3 versus 127 ± 15.1 mg dl-1, respectively). Further, total cholesterol did not change in either the experimental or control group (181.3 ± 8.7 mg dl-1 versus 178.7± 4.9 mg dl-l) and 190.7 ± 12.2 versus 197.1 ± 16.1 mg dl-1, respectively). Similarly, the ratio of TC/HDL did not change for either the experimental or control group (3.8 ± 0.4 versus 4.5 ± 0.5 and 4 ± 0.4 versus 4.2 ± 0.4, respectively). Blood triglyceride levels were also not altered in either the experimental or control group (100.3 ± 19.6 versus 114.8 ± 15.3 mg dl-1 and 140 ± 23.5 versus 137.3 ± 17.9 mg dl-l, respectively). BLOOD GLUCOSE: Fasted blood glucose levels did not change in either the experimental or control group. Pre- and post-values for experimental and control groups were 92.5 ± 4.8 versus 93.3 ± 4.3 mg dl-l and 92.3 ± 11.3 versus 93.2 ± 2.6 mg dl-1 , respectively. BLOOD PRESSURE: No aspect of blood pressure was altered in either the experimental or control group. For example, pre- and post-test systolic blood pressures were 131 ± 2 versus 129 ± 2 mmHg (experimental) and 123 ± 2 and 125 ± 2 mmHg (controls), respectively. Pre- and post-test diastolic blood pressures were 84 ± 2 and 83 ± 2 mmHg (experimental) and 81 ± 1 versus 82 ± 1 mmHg, respectively. Similarly, calculated pulse pressure was not altered in the experimental or control as pre- and post-test values were 47 ± 1 versus 47 ± 2 mmlHg and 42 ± 2 versus 43 ± 2 mmHg, respectively. FRAMINGHAM POINT SCORE: The concerted changes reported above produced an increased risk in the Framingham Point Score for the subjects in the experimental group. For example, the pre- and post-test FPS increased from 1.4 ± 0.9 to 2.7 ± 0.7. On the other hand, pre- and post-test scores for the control group were 1.8 ± 1 versus 1.8 ± 0.9. Conclusions: Our data confirms previous studies showing that interval-type exercise is a useful intervention for increasing aerobic fitness. Moreover, the increase in V02 Max we found in response to limited participation in ball hockey (i.e. 16 games) suggests that recreational sport may help reduce this aspect of coronary risk in previously sedentary individual. On the other hand, our results showing little or no positive change in body composition, blood lipids or blood pressures suggest that one season of recreational sport in not in of itself a powerful enough stimulus to reduce the overall risk of coronary artery disease. In light of this, it is recommended that, in addition to participation in recreational sport, the performance of regular physical activity is used as an adjunct to provide a more powerful overall stimulus for decreasing coronary risk factors. LIMITATIONS: The increase in the FPS we found for the experimental group, indicative of an increased risk for coronary disease, was largely due to the large decrease in HDL we observed after compared to above one season of ball hockey. In light of the fact that cardiorespiratory fitness was increased and % body fat was decreased, as well as the fact that other parameters such as blood pressure showed positive (but non statistically significant) trends, the possibility that the decrease in HDL showed by our data was anomalous should be considered. FUTURE DIRECTIONS: The results of this study suggesting that recreational sport may be a potentially useful intervention in the reduction of CAD require to be corroborated by future studies specifically employing 1) more rigorous assessment of fitness and fitness change and 2) more prolonged or frequent participants.

The role of physical activity and perceived adequacy on cardiorespiratory fitness in children with developmental coordination disorder

Evidence suggests that children with developmental coordination disorder (DCD) have lower levels of cardiorespiratory fitness (CRF) compared to children without the condition. However, these studies were restricted to field-based methods in order to predict V02 peak in the determination of CRF. Such field tests have been criticised for their ability to provide a valid prediction of V02 peak and vulnerability to psychological aspects in children with DCD, such as low perceived adequacy toward physical activity. Moreover, the contribution of physical activity to the variance in V02 peak between the two groups is unknown. The purpose of our study was to determine the mediating role of physical activity and perceived adequacy towards physical activity on V02 peak in children with significant motor impairments. This prospective case-control design involved 122 (age 12-13 years) children with significant motor impairments (n=61) and healthy matched controls (n=61) based on age, gender and school location. Participants had been previously assessed for motor proficiency and classified as a probable DCD (p-DCD) or healthy control using the movement ABC test. V02 peak was measured by a progressive exercise test on a cycle ergometer. Perceived adequacy was measured using a 7 -item subscale from Children's Selfperception of Adequacy and Predilection for Physical Activity scale. Physical activity was monitored for seven days with the Actical® accelerometer. Children with p-DCD had significantly lower V02 peak (48.76±7.2 ml/ffm/min; p:50.05) compared to controls (53.12±8.2 ml/ffm/min), even after correcting for fat free mass. Regression analysis demonstrated that perceived adequacy and physical activity were significant mediators in the relationship between p-DCD and V02 peak. In conclusion, using a stringent laboratory assessment, the results of the current study verify the findings of earlier studies, adding low CRF to the list of health consequences associated with DCD. It seems that when testing for CRF in this population, there is a need to consider the psychological barriers associated with their condition. Moreover, strategies to increase physical activity in children with DCD may result in improvement in their CRF.

Muscle strength and activation characteristics of power- trained and non-athlete boys and men

During maturation, muscle strength is enhanced through muscle growth, although neuro-muscular factors are also believed to be involved. In adults, training for power sports has been shown to enhance muscle strength and activation. The purpose of this study was to examine muscle strength and activation in power-trained athletes (POW) compared with non-athletes (CON), in boys and in adults. After familiarization subjects performed ten 5-s explosive maximal voluntary contractions for elbow and knee flexion and extension. The adults were stronger then the boys and the adult POW were stronger then the adult CON, even after correction for muscle size. Normalized rate of torque development was higher in the adults then in the boys and higher in the POW then CON boys. The rate of muscle activation was higher in the adults and POW groups. The results suggest that maturation and power-training have an additive effect on muscle activation.