The purpose was to investigate whether runners who do not squat their body weight once will not be overloaded with a weight vest with a load of 5% of BW and will not maintain 95% intensity across ten repetitions of a 20-meter sprint. Eight adult female students (24,05±1,15 years old; body height 168±4,24 cm; body weight 60,39±5,53 kg) from the faculty of sports studies at Masaryk University in the Czech Republic participated in this study. Categories were: 1 = NBW (1RM in the squat is relative body weight ± 5 kg), 2 = LBW (1RM in the squat is lower than BW-5 kg) and 3 = HBW (1RM in the squat is higher than BW +5 kg). The measurements took place on three different days, each day running with another experimental condition: free sprinting, weighted vest sprinting with a 5% load of BW, and weighted vest sprinting with a 5% load of 1RM squat. With a weight vest with resistance at the level of 5% of body weight, during 49 sprints, the intensity decreased by a maximum of 4.82% (participant 4, NBW group, 1st run). Although, with weight vest resistance at the level of 5% of the 1RM back squats, during 68 sprints, the intensity decreased by a maximum of 6.59% (participant 1, NBW group, 8th run). It seems that the level of strength abilities of the lower limbs did not play a role in this, we can calculate 5% intensity from both BW and 1 RM squat. Since the HBW group could maintain the required intensity even at significantly higher weights than 5% BW, further research with a larger research sample is needed.

The paper deals with changes in body composition (muscle mass, adipose tissue and bone mass), and changes in manifestations of maximal strength of extensors and flexors of lower and upper limbs in relation to different periods of rest (30 s, 60 s, 120 s). The research was carried out on 23 participants aged 18-30 years in natural bodybuilders of top performance, in a 5-week training intervention of bodybuilding training. At a statistical significance level of 5%, there was no significant difference in muscle tissue hypertrophy, although Group 2 (60 p.) Achieved a two-fold increase in percentage FFM compared to the other two groups, achieving a change of 1.18 %. At a statistical significance level of 5%, we noticed significant differences in the maximum force increase in knee joint flexors, and only in group 3 (120 s) by up to 11%. Significant differences in muscle strength increase were also observed in groups 2 and 3 in the elbow joint extensors and in the elbow joint flexors only in group 1.

Every cell is protected by a semipermeable membrane. Peptides with the right properties, for example Antimicrobial peptides (AMPs), can disrupt this protective barrier by formation of leaky pores. Unfortunately, matching peptide properties with their ability to selectively form pores in bacterial membranes remains elusive. In particular, the proline/glycine kink in helical peptides was reported to both increase and decrease antimicrobial activity. We used computer simulations and fluorescence experiments to show that a kink in helices affects the formation of membrane pores by stabilizing toroidal pores but disrupting barrel-stave pores. The position of the proline/glycine kink in the sequence further controls the specific structure of toroidal pore. Moreover, we demonstrate that two helical peptides can form a kink-like connection with similar behavior as one long helical peptide with a kink. The provided molecular-level insight can be utilized for design and modification of pore-forming antibacterial peptides or toxins.

• MeSH
• biologické modely MeSH
• buněčná membrána chemie   metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• kationické antimikrobiální peptidy chemie   metabolismus   MeSH
• konformace proteinů * MeSH
• metoda Monte Carlo MeSH
• molekulární modely MeSH
• poriny chemie   metabolismus   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Most strength and conditioning coaches deal with the question in the training plan, how to supplement specific exercises, or which non-specific exercises would be the most suitable for achieving the set purpose. This study aims to assess what strength transfer with a focus on the lower limbs is projected from the selected strength intervention program (the right leg exercises only single-joint exercises: leg extension on machine and leg curl; the left leg exercises only multi-joint exercises: deadlift and leg press) to the force of the knee joint flexors and extensors during the eccentric and the concentric contraction. In one training session, the participants repeated every exercise five times in four series. The load intensity was around 90% of 1RM and was increased by 5% after the first and the fifth week. The rest interval was always three minutes long. For the left lower limb, the highest transfer (0.20) was from the leg press to the knee joint extensor at the eccentric contraction and from the deadlift was the highest transfer (0.19) to the knee joint extensor at the eccentric contraction. For the right lower limb, the highest transfer (0.53) was from the leg extension on a machine to the knee joint flexor at the concentric contraction and from the lying leg curl was the highest transfer (0.47) to the knee joint flexor at the concentric contraction.

• MeSH
• bérec MeSH
• cvičení MeSH
• dolní končetina MeSH
• kosterní svaly MeSH
• lidé MeSH
• techniky cvičení a pohybu * MeSH
• Check Tag
• lidé MeSH

PURPOSE The purpose of this study was to find out whether a more specific stimulus, such as training which stimulates the production of power above 90% of Pmax (Pmax = maximal average concentric power output), is effective in enhancing the countermovement jump (CMJ) performance using the method of complex pairs or separate execution of the exercises in the complex pair (separate complex pair). METHODS Thirty male students of the Faculty of Sports Studies were divided into 2 experimental (EX1, EX2) and 1 control group (CNTR). The experimental groups trained for 8 weeks using the complex training (CT) method twice a week with the same amount of repetitions for each exercise. The complex pair consisted of half-squat jumps with the intensity over 90% of Pmax and plyometric depth-jumps. EX1 trained using the complex pair method with the intracomplex rest interval of up to 15 seconds. EX2 trained all sets of the half-squat jumps first and then all sets of the plyometric exercise. We used non-parametric statistics and linear regression analysis to evaluate the effect on increasing the CMJ performance after the intervention program. RESULTS There were no significant differences between the pre-test and post-test in any of the experimental groups (p > 0.05), although there were significant differences between the weeks in EX1 and EX2 (p < 0.05). The CMJ performance increased insignificantly (p > 0.05) each week by 0.14 cm in EX1 and by 0.07 cm in EX2. CONCLUSION These results did not clearly show the application of the CT methods to be useful in enhancing the CMJ. In practice we recommend using the complex pairs to save training time and increase training intensity. However, an additional longer-term intervention experiment with a bigger sample size and groups randomized by the CMJ parameter (not by Pmax) is needed.

• MeSH
• biomechanika MeSH
• lidé MeSH
• pohybová aktivita MeSH
• svalová síla * MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH

PURPOSE Many types of vertical jumps (VJ) are commonly used to assess the development of the level of explosive strength of lower limbs achieved after a training period. This study is focused on comparing various parameters of different types of VJ with 1 RM in Olympic-style weightlifting, squat and deadlift with an Olympic bar. he snatch r=0.8 r2= 0.64, clean and jerk r=0.81 r2= 0.65, back squat r=0.82 r2= 0.67 and deadlift r=0.78 r2= 0.60; for the SJ with hands on the hips and the snatch r= 0.76 r2= 0.57, clean and jerk r= 0.75 r2= 0.56, back squat r= 0.77 r2= 0.59 and deadlift r= 0.71 r2= 0.50. Significant correlation coefficients were not found for 1 RM in the snatch, clean and jerk, back squat and deadlift and the CMJ or SJ with and without arm swing in any of the following parameters: jump height (m), relative force (% of body weight), relative power output (W/kg of body weight). CONCLUSION The main finding is that the jump height (m) of the CMJ or SJ with or without arm swing did not correlate significantly with 1 RM in the snatch, clean and jerk, back squat and deadlift. Therefore, jump height measurement can be used as a motivation tool but not to predict maximum strength in Olympic bar exercises, or vice versa. We recommend using the average power output (W) parameter in the CMJ with using arms as a predictor of current performance level in exercises with an Olympic bar for men and women.

• MeSH
• lidé MeSH
• pohybová aktivita MeSH
• sportovci MeSH
• sportovní výkon MeSH
• tělesná námaha MeSH
• vzpírání * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

The relationship between the muscular strength of hamstrings and quadriceps and their possible muscular imbalance is considered by many authors as one of the causes of knee joint injury. The aim of this work is to assess the exercise program including squat modifications both in terms of progression of lower limb strength and in terms of possible change of H: Q ratio. Probands were divided into five groups (one control, four experimental). The experimental groups practiced the intervention program twice a week for eight weeks (EX1: Barbell squat, EX2: Barbell half squat, EX3: Barbell half squat with countermovement). In one training session participants repeated the exercise five times in six series. All experimental groups exhibited significant differences in mean values (p < 0.01), indicating the progression of lower limb strength measured by 1RM for barbell squat. The differences in the mean values of the H: Q ratio measured on an isokinetic dynamometer in the isokinetic test mode at angular velocities of 60 and 300 degrees per second do not show statistically significant differences (p = 0.99338). The established strength intervention program is suitable for the development of lower limb strength and does not show any changes in the H: Q ratio.

• MeSH
• biomechanika MeSH
• čtyřhlavý sval stehenní MeSH
• kolenní kloub * patologie   MeSH
• lidé MeSH
• sportovní úrazy MeSH
• svalová síla MeSH
• techniky cvičení a pohybu MeSH
• zadní stehenní svaly MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

Positive selection acting on Toll-like receptors (TLRs) has been recently investigated to reveal evolutionary mechanisms of host-pathogen molecular co-adaptation. Much of this research, however, has focused mainly on the identification of sites predicted to be under positive selection, bringing little insight into the functional differences and similarities among species and a limited understanding of convergent evolution in the innate immune molecules. In this study, we provide evidence of phenotypic variability in the avian TLR4 ligand-binding region (LBR), the direct interface between host and pathogen molecular structures. We show that 55 passerine species vary substantially in the distribution of electrostatic potential on the surface of the receptor, and based on these distinct patterns, we identified four species clusters. Seven of the 34 evolutionarily nonconservative and positively selected residues correspond topologically to sites previously identified as being important for lipopolysaccharide, lipid IVa or MD-2 binding. Five of these positions codetermine the identity of the charge clusters. Groups of species that host-related communities of pathogens were predicted to cluster based on their TLR4 LBR charge. Despite some evidence for convergence among taxa, there were no clear associations between the TLR4 LBR charge distribution and any of the general ecological characteristics compared (migration, latitudinal distribution and diet). Closely related species, however, mostly belonged to the same surface charge cluster indicating that phylogenetic constraints are key determinants shaping TLR4 adaptive evolution. Our results suggest that host innate immune evolution is consistent with Fahrenholz's rule on the cospeciation of hosts and their parasites.

• MeSH
• glykolipidy chemie   genetika   MeSH
• interakce hostitele a patogenu genetika   MeSH
• konformace proteinů MeSH
• ligandy MeSH
• lipid A analogy a deriváty   chemie   genetika   MeSH
• lipopolysacharidy chemie   genetika   MeSH
• lymfocytární antigen 96 chemie   genetika   MeSH
• mikrobiota genetika   MeSH
• molekulární evoluce * MeSH
• molekulární modely MeSH
• přirozená imunita genetika   MeSH
• ptáci genetika   parazitologie   MeSH
• sekvenční analýza DNA MeSH
• selekce (genetika) * genetika   MeSH
• statická elektřina MeSH
• toll-like receptor 4 chemie   genetika   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Weightlifting heavy load exercises are commonly used as a key instrument for enhancing performance if compared to those not using the exercise stimulating muscle tone. Studies examined the post-activation effect (PAP) using only one parameter but not in consecutive and intermingling exercises to prolongated the time of the PAP effect duration and maintain increased performance. Nine male students, with resistance training experience, performed warm-up and exercises enhancing muscle tone (EEMT) using squats to 90° flexion in the knee joint with 80 % 1 RM (repetition maximum) in 3 sets with 3 repetitions of squat in each set (2-3 min. rest intervals). After EEMT they performed a 10-m sprint test in 2nd and 5th min, the countermovement long jump (CLJ) test in the 5th and 6th minute, a 10-m sprint test in the 10th and 11th minute and the CLJ test in the 12th and 14th minute. The results showed that the average improvement was in 10-m sprint after EEMT 0,013 ± 0,05 seconds, but there were no statistical differences observed between the result without and with EEMT (p>0.05). We observed a significant improvement between jumps without and with EEMT in 5 – 14th min (p<0.05). There were no statistical differences between the results in CLJ carried out in 5-6th min after EEMT and after two 10-m sprints and the results carried out in 12-14th min. after EEMT, four 10-m sprints and two jumps (p>0.05). It was found that 10-m sprint has no negative effect on performance in the long jump and could be regularly applied to prolong the PAP effect.

• Klíčová slova
• dřep,
• MeSH
• běh fyziologie   MeSH
• lidé MeSH
• sportovci MeSH
• sportovní výkon MeSH
• Check Tag
• lidé MeSH

Sex determination in Rumex acetosa, a dioecious plant with a complex XY1 Y2 sex chromosome system (females are XX and males are XY1 Y2 ), is not controlled by an active Y chromosome but depends on the ratio between the number of X chromosomes and autosomes. To gain insight into the molecular mechanisms of sex determination, we generated a subtracted cDNA library enriched in genes specifically or predominantly expressed in female floral buds in early stages of development, when sex determination mechanisms come into play. In the present paper, we report the molecular and functional characterization of FEM32, a gene encoding a protein that shares a common architecture with proteins in different plants, animals, bacteria and fungi of the aerolysin superfamily; many of these function as β pore-forming toxins. The expression analysis, assessed by northern blot, RT-PCR and in situ hybridization, demonstrates that this gene is specifically expressed in flowers in both early and late stages of development, although its transcripts accumulate much more in female flowers than in male flowers. The ectopic expression of FEM32 under both the constitutive promoter 35S and the flower-specific promoter AP3 in transgenic tobacco showed no obvious alteration in vegetative development but was able to alter floral organ growth and pollen fertility. The 35S::FEM32 and AP3::FEM32 transgenic lines showed a reduction in stamen development and pollen viability, as well as a diminution in fruit set, fruit development and seed production. Compared with other floral organs, pistil development was, however, enhanced in plants overexpressing FEM32. According to these effects, it is likely that FEM32 functions in Rumex by arresting stamen and pollen development during female flower development. The aerolysin-like pore-forming proteins of eukaryotes are mainly involved in defence mechanisms against bacteria, fungi and insects and are also involved in apoptosis and programmed cell death (PCD), a mechanism that could explain the role of FEM32 in Rumex sex determination.

• MeSH
• bakteriální toxiny klasifikace   genetika   MeSH
• cytotoxické proteiny tvořící póry klasifikace   genetika   MeSH
• fylogeneze MeSH
• geneticky modifikované rostliny MeSH
• květy genetika   růst a vývoj   MeSH
• neplodnost rostlin genetika   MeSH
• ovoce genetika   růst a vývoj   MeSH
• pyl genetika   růst a vývoj   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny klasifikace   genetika   MeSH
• Rumex genetika   růst a vývoj   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• semena rostlinná genetika   růst a vývoj   MeSH
• stanovení celkové genové exprese metody   MeSH
• tabák genetika   růst a vývoj   MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH