Effects of Futsal Demands on Serum and Salivary Levels of Trace Elements and Minerals Detected by Total Reflection X-Ray Fluorescence

Circulating Concentration of Chemical Elements During Exercise-Induced Muscle Damage and the Repeated Bout Effect

The objective of the study was to evaluate the circulating levels of chemical elements after exercise-induced muscle damage (EIMD) followed by the repeated bout effect (RBE). Seven physically active subjects (26.5 ± 4.0 years) performed two sessions of EIMD (5 sets of 20 drop jumps), the second session 14 days after the first for RBE assessment. Blood collections, countermovement jump (CMJ), squat jump (SJ), and delayed-onset muscle soreness (DOMS) were performed before (Pre), after (Post), and 24, 48, and 72 h after the exercise session. Creatine kinase (CK) was detected by biochemical analysis and the concentration of chemical elements by total reflection X-ray fluorescence (TXRF). Differences between time points and sessions were assessed with two-way ANOVA and the effect size (ES). EIMD induced a reduction in the CMJ at 24 h (P < 0.05) and an increase in DOMS at 24 h (P < 0.01) and 48 h (P < 0.01), and CK at 72 h (P < 0.05). RBE alleviated all symptoms of EIMD in the second session (P > 0.05). EIMD induced a large to very large ES for Zn reduction at 24 h (- 1.37) and 72 h (- 0.93) and Br (- 0.83) at 72 h. RBE presented large to very large ES for the increase in P at 48 h (0.92); Cl at 24 h (1.04); K at 24 h (0.91), 48 h (1.10), and 72 h (0.96); Ca at 72 h (0.92); and Fe at 24 h (0.85). RBE influenced the concentration of elements associated with fatigue (K, Ca, Cl), inflammatory response, and glucose metabolism (Zn).

Further assessments of ligase LplA-mediated modifications of proteins in vitro and in cellulo

BACKGROUND

Posttranslational modifications of proteins are catalyzed by a large family of enzymes catalyzing many chemical modifications. One can hijack the natural use of those enzymes to modify targeted proteins with synthetic chemical moieties. The lipoic acid ligase LplA mutants can be used to introduce onto the lysine sidechain lipoic acid moiety synthetic analogues. Substrate protein candidates of the ligase must obey a few a priori rules.

METHODS AND RESULTS

In the present report, we technically detailed the use of a cell line stably expressing both the ligase and a model protein (thioredoxin). Although the goal can be reach, and the protein visualized in situ, many experimental difficulties must be fixed. The sequence of events comprises (i) in cellulo labeling of the target protein with a N₃-lipoic acid derivative catalyzed by the mutant ligase, (ii) the further introduction by click chemistry onto this lysine sidechain of a fluorophore and (iii) the following of the labeled protein in living cells. One of the main difficulties was to assess the click chemistry step onto the living cells, because images from both control and experimental cells were similar. Alternatively, we describe at that stage, the preferred use of another technique: the Halo-Tag one that led to the obtention of clear images of the targeted protein in its cellular context. Although the ligase-mediated labeling of protein in situ is a rich domain for which many cellular tools must be developed, many difficulties must be considered before entering a systematic use of this approach.

CONCLUSIONS

In the present contribution, we added several steps of analytical characterization, both in vitro and in cellulo that were previously lacking. Furthermore, we show that the use of the click chemistry should be manipulated with care, as the claimed specificity might be not complete whenever living cells are used. Finally, we added another approach-the Halo Tag-to complete the previously suggested approaches for labelling proteins in cells, as we found difficult to strictly apply the previously reported methodology.

Relationship between Training Load Management and Immunoglobulin A to Avoid Immunosuppression after Soccer Training and Competition: A Theoretical Framework Based on COVID-19 for Athletes' Healthcare

Immunoglobulin A (IgA), which is the main effector against upper respiratory tract viruses such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been related to training load management. The aim of this systematic review was to establish the relationship between training load and salivary IgA based on current evidence in order to avoid immunosuppression after exercise and players´ vulnerability to virus contagion. A systematic review of relevant articles was carried out using two electronic databases (PubMed and Web of Science) until 19 May 2021. From a total of 127 studies initially found, 23 were included in the qualitative synthesis. These studies were clustered depending on stress level. The salivary IgA was analysed considering soccer-specific treadmill exercise and repeated sprint drills (n = 5), matches (n = 7), and during certain periods during the season or pre-season (n = 11). Repeated sprint ability tests and treadmill exercises are suitable exercises for the first steps on return to play periods yet still maintain social distance. A rest or moderate training sessions (technical/tactical) are suggested after official matches to ensure 16-18 h to recover IgA levels, while periods with multiple matches per week with limited recovery time should be avoided. Weekly training load should assume a small increment (<10%) to ensure IgA immune responses, especially, during the post coronavirus disease 2019 (COVID-19) season.

Analytical potential of total reflection X-ray fluorescence spectrometry for simultaneous determination of iron, copper and zinc in human blood serum and plasma

Due to many roles of trace elements such as Fe, Cu and Zn in various physiological and pathophysiological processes, their determination in serum and plasma is of high clinical relevance. In the present study, for the first time, the effect of serum and plasma preparation parameters (dilution factor and sample deposition volume) on the quality of results obtained by TXRF analysis was evaluated by means of experimental design tools (response surface analysis). It was found that the best strategy was the direct analysis of both human fluids without a previous dilution step. The accuracy and precision of the proposed methods were evaluated by analysis of reference materials (ClinChek® Plasma Control Level II and Seronorm™ Trace Elements Serum L-1). TXRF results agreed with the reference values and no significant differences at 95% confidence level were found. Limits of detection for the elements of interest were also adequate, taking into account their typical concentration ranges in real serum and plasma samples. Finally, the developed TXRF methods were applied to a set of serum and plasma samples from patients with different genders, ages and diagnoses, previously analysed by ICP-OES and ICP-MS techniques. The results showed good agreement between both analytical approaches. These results suggest that the proposed TXRF method provides reliable results thus being suitable for plasma and serum analysis, but in a simpler and more sustainable way.

Monitoring and Behavior of Biomotor Skills in Futsal Athletes During a Season

Futsal is a sport that presents alternation of high and low intensity moments, which lacks investigations regarding the effects of the organization of the training load on biomotor skills. In this sense, this study aims to verify the monitoring of the training load throughout the season and the behavior of biomotor skills in futsal athletes. Twelve futsal athletes (24.5 ± 4.9 years, 1.79 ± 0.6 m, 72.4 ± 9.4 kg, and 9.4 ± 4.3% fat) from the adult category who competed in the first division of the Paulista championship participated in the study. Throughout the season the internal training load (ITL) was calculated, through the relationship between volume (minutes) and the rate of perceived exertion (RPE), monotony, and training strain. The training periods were divided into: preparatory, competitive and competitive II, for a total of four moments of evaluation: M1: at the beginning of the preparatory period; M2: 5th week, at the end of the preparatory period; M3: 13th week, in the middle of the competitive period; and M4: at the start of the competitive period II. The tests used were: (i) Power of lower limbs: counter movement jump (CMJ); (ii) Displacement speed, over the 10-meter distance (V10m); and (iii) Aerobic power, by the Carminatti test (T-CAR). The variables analyzed were compared at the different moments of evaluation, normally distributed variables (Volume, S-RPE, strain, and monotony) were analyzed using the ANOVA ONE-WAY variance test followed by the Tukey. Variables that did not show normality (lower limb power, speed, and aerobic power) were compared using the Friedman test followed by Dunn's multiple comparisons test and was presented by median and interquartile interval. The significance value adopted was p < 0.05. A significant improvement (p < 0.05) was observed in the power of lower limbs from M1 (37.5 ± 5.5 cm) to M3 (40.8 ± 5.7 cm), from M2 (38.9 ± 5.5 cm) to M3 (40.8 ± 5.7 cm), and from M1 (37.5 ± 5.5 cm) to M4 (40.2 ± 5.4 cm). Aerobic power showed a significant increase (p < 0.05) from M1 (12.1 ± 0.7 km/h) to M3 (12.7 ± 7 km/h) and from M1 (12.1 ± 0.7 km/h) to M4 (12.73 ± 1.04 km/h). The internal training load showed a difference between competitive I and II in relation to the preparatory period (p < 0.05). In conclusion, the proposed training organization was sufficient to improve the power of the lower limbs and the aerobic power.