The Importance of Selected Coordination Motor Skills for an Individual Football Player’s Effectiveness in a Game

The appropriate level of coordination motor skills (CMS) in a football player is one of the factors determining the effectiveness of their actions. Adaptability and complex reaction time are of particular importance in models of coordination requirements in football. The lead aim of this study is to determine the relationship between two selected coordination motor skills and the offensive, defensive and comprehensive effectiveness of an individual player’s actions. The study was conducted on a group of 91 Polish male football players aged 20 to 31 years, all in the senior age category. The research tools included: a test assessing motor adaptation (research by dribbling the ball with the dominant leg), psychomotor test of complex reaction time (tested with an S-10.2 measuring device) and a test of the effectiveness of an individual player’s actions (one-on-one simulation game). The conducted research indicated that adaptability and complex reaction time are both important abilities for success when attacking in an individual game, and in the assessment of a comprehensive index of individual competences in a one-on-one football game. However, the most significant factor influencing the effectiveness of a player’s defensive action is solely the complex reaction time.

A mathematical model for the dependence of keratin aggregate formation on the quantity of mutant keratin expressed in EGFP-K14 R125P keratinocytes

We examined keratin aggregate formation and the possible mechanisms involved. With this aim, we observed the effect that different ratios between mutant and wild-type keratins expressed in cultured keratinocytes may have on aggregate formation in vitro, as well as how keratin aggregate formation affects the mechanical properties of cells at the cell cortex. To this end we prepared clones with expression rates as close as possible to 25%, 50% and 100% of the EGFP-K14 proteins (either WT or R125P and V270M mutants). Our results showed that only in the case of the 25% EGFP-K14 R125P mutant significant differences could be seen. Namely, we observed in this case the largest accumulation of keratin aggregates and a significant reduction in cell stiffness. To gain insight into the possible mechanisms behind this observation, we extended our previous mathematical model of keratin dynamics by implementing a more complex reaction network that considers the coexistence of wild-type and mutant keratins in the cell. The new model, consisting of a set of coupled, non-linear, ordinary differential equations, allowed us to draw conclusions regarding the relative amounts of intermediate filaments and aggregates in cells, and suggested that aggregate formation by asymmetric binding between wild-type and mutant keratins could explain the data obtained on cells grown in culture.

Determination of fighting styles of qualified veteran boxers based on cluster analysis of biomechanical and psychophysiological indicators

Purpose: to reveal the styles of fighting veteran boxers on the basis of a multivariate analysis of psychophysiological and biomechanical indicators. Material and methods. The study involved 42 qualified veteran boxers (age 45-50 years). As research methods, we used a biomechanical analysis of the indicators of the speed of movement of various points and the values ​​of the angles in the joints when performing a direct blow by boxers. The psychophysiological method was used to determine the time of a simple and complex reaction under standard conditions and in various testing modes. We used the method of cluster analysis to distribute athletes into groups using the SPSS - 17.0 program. Within the groups, the athletes are as similar as possible to each other in terms of the analyzed indicators, and between the groups they differ as much as possible. The analysis of the groups of athletes obtained with the help of cluster analysis made it possible to identify athletes with the following styles of fighting: tempo, game, power. Results. Cluster analysis of psychophysiological and biomehanical testing showed the presence of 3 groups of athletes. The clusters were named as follows: Cluster 1 - "Speed and coordination endurance", corresponds to the boxers of the pace of the fight; Cluster 2 - "Speed", corresponds to the boxers of the game style of fighting; Cluster 3 - "Strength and speed", corresponds to the boxers of the pace of the fight. Biomechanical features of boxers of different styles of fighting are reflected in the trajectories of the points of the fist, elbow, knee. Conclusions. The results of this study should be used when planning the individual training of athletes in boxing and to determine the optimal style of competitive competition for qualified veteran boxers. The proposed methods of psychophysiological and biomechanical testing to determine the individual characteristics of boxers are an effective, fairly accessible and convenient tool for revealing the predisposition of boxers to a certain style of fighting.

The crystal structures of the enzyme hydroxymethylbilane synthase, also known as porphobilinogen deaminase

The enzyme hydroxymethylbilane synthase (HMBS; EC 4.3.1.8), also known as porphobilinogen deaminase, catalyses the stepwise addition of four molecules of porphobilinogen to form the linear tetrapyrrole 1-hydroxymethylbilane. Thirty years of crystal structures are surveyed in this topical review. These crystal structures aim at the elucidation of the structural basis of the complex reaction mechanism involving the formation of tetrapyrrole from individual porphobilinogen units. The consistency between the various structures is assessed. This includes an evaluation of the precision of each molecular model and what was not modelled. A survey is also made of the crystallization conditions used in the context of the operational pH of the enzyme. The combination of 3D structural techniques, seeking accuracy, has also been a feature of this research effort. Thus, SAXS, NMR and computational molecular dynamics have also been applied. The general framework is also a considerable chemistry research effort to understand the function of the enzyme and its medical pathologies in acute intermittent porphyria (AIP). Mutational studies and their impact on the catalytic reaction provide insight into the basis of AIP and are also invaluable for guiding the understanding of the crystal structure results. Future directions for research on HMBS are described, including the need to determine the protonation states of key amino-acid residues identified as being catalytically important. The question remains – what is the molecular engine for this complex reaction? Thermal fluctuations are the only suggestion thus far.

A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The complexity gap between the biotic and abiotic worlds has made explaining abiogenesis one of the hardest scientific questions. A promising strategy for addressing this problem is to identify features shared by abiotic and biotic chemical systems that permit the stepwise accretion of complexity. Therefore, we compared abiotic and biotic reaction networks in order to evaluate the presence of autocatalysis, the underlying basis of biological self-propagation, and to see if the organization of autocatalytic motifs permits stepwise complexification. We provide an algorithm to detect seed-dependent autocatalytic systems (SDASs), namely subnetworks that can use food chemicals to self-propagate but must be seeded by some non-food chemicals to become activated. We show that serial activation of SDASs can cause incremental complexification. Furthermore, we identify life-like features that emerge during the accretion of SDASs, including the emergence of new ecological opportunities and improvements in the efficiency of food utilization. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify without the need for genetic polymers. This framework also suggests experiments that have the potential to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems.

A mechanism of abiogenesis based on complex reaction networks organized by seed-dependent autocatalytic systems

The complexity gap between the biotic and abiotic worlds has made explaining abiogenesis one of the hardest scientific questions. A promising strategy for addressing this problem is to identify features shared by abiotic and biotic chemical systems that permit the stepwise accretion of complexity. Therefore, we compared abiotic and biotic reaction networks in order to evaluate the presence of autocatalysis, the underlying basis of biological self-propagation, and to see if the organization of autocatalytic motifs permits stepwise complexification. We provide an algorithm to detect seed-dependent autocatalytic systems (SDASs), namely subnetworks that can use food chemicals to self-propagate but must be seeded by some non-food chemicals to become activated. We show that serial activation of SDASs can cause incremental complexification. Furthermore, we identify life-like features that emerge during the accretion of SDASs, including the emergence of new ecological opportunities and improvements in the efficiency of food utilization. The SDAS concept explains how driven abiotic environments, namely ones receiving an ongoing flux of food chemicals, can incrementally complexify without the need for genetic polymers. This framework also suggests experiments that have the potential to detect the spontaneous emergence of life-like features, such as self-propagation and adaptability, in driven chemical systems.