[The efficiency of branched chain aminoacids (BCAA) in the nutrition of combat sport athletes]

The combined analysis of urine and blood metabolomics profiles provides an accurate prediction of the training and competitive status of Chinese professional swimmers

Objective: The purpose of this study was to employ metabolomics for the analysis of urine metabolites in swimmers, with the aim of establishing models for assessing their athletic status and competitive potential. Furthermore, the study sought to compare the identification efficacy of multi-component (urine and blood) model versus single-component (urine or blood) models, in order to determine the optimal approach for evaluating training and competitive status. Methods: A total of 187 Chinese professional swimmers, comprising 103 elite and 84 sub-elite level athletes, were selected as subjects for this study. Urine samples were obtained from each participant and subjected to nuclear magnetic resonance (NMR) metabolomics analysis. Significant urine metabolites were screened through multivariable logistic regression analysis, and an identification model was established. Based on the previously established model of blood metabolites, this study compared the discriminative and predictive performance of three models: either urine or blood metabolites model and urine + blood metabolites model. Results: Among 39 urine metabolites, 10 were found to be significantly associated with the athletic status of swimmers (p < 0.05). Of these, levels of 2-KC, cis-aconitate, formate, and LAC were higher in elite swimmers compared to sub-elite athletes, while levels of 3-HIV, creatinine, 3-HIB, hippurate, pseudouridine, and trigonelline were lower in elite swimmers. Notably, 2-KC and 3-HIB exhibited the most substantial differences. An identification model was developed to estimate physical performance and athletic level of swimmers while adjusting for different covariates and including 2-KC and 3-HIB. The urine metabolites model showed an area under the curve (AUC) of 0.852 (95% CI: 0.793-0.912) for discrimination. Among the three identification models tested, the combination of urine and blood metabolites showed the highest performance than either urine or blood metabolites, with an AUC of 0.925 (95% CI: 0.888-0.963). Conclusion: The two urine metabolites, 2-KC and 3-HIV, can serve as significant urine metabolic markers to establish a discrimination model for identifying the athletic status and competitive potential of Chinese elite swimmers. Combining two screened urine metabolites with four metabolites reported exhibiting significant differences in blood resulted in improved predictive performance compared to using urine metabolites alone. These findings indicate that combining blood and urine metabolites has a greater potential for identifying and predicting the athletic status and competitive potential of Chinese professional swimmers.

Metabolic engineering of Corynebacterium glutamicum for producing branched chain amino acids

Background

Branched chain amino acids (BCAAs) are widely applied in the food, pharmaceutical, and animal feed industries. Traditional chemical synthetic and enzymatic BCAAs production in vitro has been hampered by expensive raw materials, harsh reaction conditions, and environmental pollution. Microbial metabolic engineering has attracted considerable attention as an alternative method for BCAAs biosynthesis because it is environmentally friendly and delivers high yield.

Main text

Corynebacterium glutamicum (C. glutamicum) possesses clear genetic background and mature gene manipulation toolbox, and has been utilized as industrial host for producing BCAAs. Acetohydroxy acid synthase (AHAS) is a crucial enzyme in the BCAAs biosynthetic pathway of C. glutamicum, but feedback inhibition is a disadvantage. We therefore reviewed AHAS modifications that relieve feedback inhibition and then investigated the importance of AHAS modifications in regulating production ratios of three BCAAs. We have comprehensively summarized and discussed metabolic engineering strategies to promote BCAAs synthesis in C. glutamicum and offer solutions to the barriers associated with BCAAs biosynthesis. We also considered the future applications of strains that could produce abundant amounts of BCAAs.

Conclusions

Branched chain amino acids have been synthesized by engineering the metabolism of C. glutamicum. Future investigations should focus on the feedback inhibition and/or transcription attenuation mechanisms of crucial enzymes. Enzymes with substrate specificity should be developed and applied to the production of individual BCAAs. The strategies used to construct strains producing BCAAs provide guidance for the biosynthesis of other high value-added compounds.

Association between dietary essential amino acids intake and metabolic biomarkers: influence of obesity among Chinese children and adolescents

Essential amino acids (EAAs) are involved in growth and development in children and adolescents. This study was aimed at exploring the relationship between dietary EAA intakes and metabolic biomarker, and the influence of obesity in children and adolescents. A total of 3566 subjects were analysed. Participators were classified according to weight status. Metabolic biomarkers were determined using standardized methods and conditions. Normal, overweight, and obesity statuses were defined according to the Working Group on Obesity in China (WGOC) BMI cutoff points based on age- and sex-specific screening criteria. In normal-weight group, blood uric acid was negatively correlated with dietary Ile, Leu, Lys, Phe, Thr, Val, and His, and zinc was negatively correlated with Ile, Leu, Lys, Phe, Thr, Val, His, Met, and Trp. In overweight group, TC was negatively correlated with Ile, Leu, Phe, Val, and His, and LDL-C was negatively correlated with Ile, Leu, Lys, Phe, Thr, Val, His, and Met, while TG was positively correlated with Leu, Lys, Phe, Thr, Val, and Met. In obesity group, hemoglobin was positively related to Ile, Leu, Lys, Phe, Thr, Val, His, and Trp, while vitamin D was positively correlated with His and Trp. The serum creatinine was negatively correlated with Ile, Leu, Phe, Val, His, and Met in normal-weight group, and positively correlated with Ile, Leu, Lys, Phe, Thr, Val, His, Met, Trp, His, and Trp in obesity group. Dietary amino acid score (AAS) and Leu intake were protective factors for obesity. The association between fasting blood glucose and EAAs intake was weak and labile. Metabolic biomarkers and EAA intakes were only related under certain weight status. The dietary AAS is positively correlated with HDL-C, LDL-C, serum creatinine, albumin, serum vitamin D, and zinc. The subtle relationship of EAAs and kidney function should be explored further. There is a complex relationship between EAAs and metabolic biomarkers, and overweight and obesity have a certain influence on this relationship.