The Effects Carbohydrate Loading Has on Aerobic Performance

The purpose of this research was to determine the effects of drinking a carbohydrate sports drink compared to a placebo drink before 35 minutes of strenuous aerobic exercise (70-75% of Max Heart Rate). Perceived rate of exertion, work load, blood glucose levels, and heart rates were collected from non-athletes at a Northwest College. Nine participants were randomly provided a placebo or carbohydrate drink 1 hour before each trial after fasting for ten hours. Each participant completed four trials with three days’ rest between trials. Based on the results there was a significant difference in work output between the placebo and treatment trials (p = 0.019253267), which resulted in a 5% greater work output for participants who consumed the carbohydrate drink. Participants always reported a lower rate of perceived exertion when consuming the carbohydrate drink. In conclusion participants were able to cycle a longer distance in the 35 minute trials after consuming the carbohydrate drink. The perceived rate of exertion difference between trials was more noticeable in the late stages of the trials. It may be beneficial to increase length of the trials to longer than an hour to determine if there is a greater benefit of carbohydrate loading in longer trials

Female Collegiate Dancers Body Composition, Macronutrient and Micronutrient Intake Over Two Academic Years: A Longitudinal Analysis

Collegiate dancers face unique challenges to maintain a lean aesthetic, optimal diet, and a high-performance level due to the various stressors in college. The purpose of this study was to examine changes in body composition (BC) and diet over two years. Participants (N = 17, 19.6 ± 1.6 years) completed two laboratory sessions per semester. Sessions included height and weight, BC, dietary intake, and a health history questionnaire. Regardless of rigorous dance training and variations in the academic calendar, no significant changes in BC or diet were observed within semesters of over two years. BMI was normal (24.9 ± 4.1 kg/m2) with fat mass exceeding 30% at all timepoints. Fat mass was negatively correlated with carbohydrate, fat, and protein intake (g/kg/day; r = −0.291, p = 0.004; r = −0.372, p < 0.0001; r = −0.398, p < 0.0001; respectively). Energy intake was within the recommended daily allowance (2040 ± 710 kcal/day), however may be insufficient for an active dance population. Protein (1.1 ± 0.5 g/kg), carbohydrate (3.7 ± 1.6 g/kg), calcium (835 ± 405 mg/day), iron (17 ± 15 mg/day), and potassium (1628 ± 1736 mg/day) intake fell below recommendations for an active population. Alterations in dance training and the demands of the academic calendar may be contributing to suboptimal dietary intake and BC in female collegiate dancers

Directed evolution reveals requisite sequence elements in the functional expression of P450 2F1 in Escherichia coli

Cytochrome P450 2F1 (P450 2F1) is expressed exclusively in the human respiratory tract and is implicated in 3-methylindole (3MI)-induced pneumotoxicity via dehydrogenation of 3MI to a reactive electrophilic intermediate, 3-methyleneindolenine (3-MEI). Studies of P450 2F1 to date have been limited by the failure to express this enzyme in Escherichia coli. By contrast, P450 2F3, a caprine homologue that shares 84% sequence identity with P450 2F1 (86 amino acid differences), has been expressed in E. coli at yields greater than 250 nmol/L culture. We hypothesized that a limited number of sequence differences between P450s 2F1 and 2F3 could limit P450 2F1 expression in E. coli and that problematic P450 2F1 sequence elements could be identified by directed evolution. A library of P450 2F1/2F3 mutants was created by DNA family shuffling and screened for expression in E. coli. Three generations of DNA shuffling revealed a mutant (named JH_2F_F3_1_007) with 96.5% nucleotide sequence identity to P450 2F1 and which expressed 119 +/- 40 pmol (n = 3, mean +/- SD) hemoprotein in 1 mL microaerobic cultures. Across all three generations, two regions were observed where P450 2F3-derived sequence was consistently substituted for P450 2F1 sequence in expressing mutants, encoding nine amino acid differences between P450s 2F1 and 2F3: nucleotides 191-278 (amino acids 65-92) and 794-924 (amino acids 265-305). Chimeras constructed to specifically test the importance of these two regions confirmed that P450 2F3 sequence is essential in both regions for expression in E. coli but that other non-P450 2F1 sequence elements outside of these regions also improved the expression of mutant JH_2F_F3_1_007. Mutant JH_2F_F3_1_007 catalyzed the dehydrogenation of 3MI to 3-MET as indicated by the observation of glutathione adducts after incubation in the presence of glutathione. The JH_2F_F3_1_007 protein differs from P450 2F1 at only 20 amino acids and should facilitate further studies of the structure activity relationships of P450s of the 2F subfamily