Physiological and anthropometric determinants of critical power, W ′ and the reconstitution of W ′ in trained and untrained male cyclists

From Springer Nature via Jisc Publications RouterHistory: received 2020-01-17, accepted 2020-07-31, registration 2020-08-01, pub-electronic 2020-08-09, online 2020-08-09, pub-print 2020-11Publication status: PublishedAbstract: Purpose: This study examined the relationship of physiological and anthropometric characteristics with parameters of the critical power (CP) model, and in particular the reconstitution of W′ following successive bouts of maximal exercise, amongst trained and untrained cyclists. Methods: Twenty male adults (trained nine; untrained 11; age 39 ± 15 year; mass 74.7 ± 8.7 kg; V̇O2max 58.0 ± 8.7 mL kg−1 min−1) completed three incremental ramps (20 W min−1) to exhaustion interspersed with 2-min recoveries. Pearson’s correlation coefficients were used to assess relationships for W′ reconstitution after the first recovery (W′rec1), the delta in W′ reconstituted between recoveries (∆W′rec), CP and W′. Results: CP was strongly related to V̇O2max for both trained (r = 0.82) and untrained participants (r = 0.71), whereas W′ was related to V̇O2max when both groups were considered together (r = 0.54). W′rec1 was strongly related to V̇O2max for the trained (r = 0.81) but not untrained (r = 0.18); similarly, ∆W′rec was strongly related to V̇O2max (r = − 0.85) and CP (r = − 0.71) in the trained group only. Conclusions: Notable physiological relationships between parameters of aerobic fitness and the measurements of W′ reconstitution were observed, which differed among groups. The amount of W′ reconstitution and the maintenance of W′ reconstitution that occurred with repeated bouts of maximal exercise were found to be related to key measures of aerobic fitness such as CP and V̇O2max. This data demonstrates that trained cyclists wishing to improve their rate of W′ reconstitution following repeated efforts should focus training on improving key aspects of aerobic fitness such as V̇O2max and CP

GoLoco motif proteins binding to Gαi1: insights from molecular simulations

Molecular dynamics simulations, computational alanine scanning and sequence analysis were used to investigate the structural properties of the Gαi1/GoLoco peptide complex. Using these methodologies, binding of the GoLoco motif peptide to the Gαi1 subunit was found to restrict the relative movement of the helical and catalytic domains in the Gαi1 subunit, which is in agreement with a proposed mechanism of GDP dissociation inhibition by GoLoco motif proteins. In addition, the results provide further insights into the role of the “Switch IV” region located within the helical domain of Gα, the conformation of which might be important for interactions with various Gα partners

Structural basis of phosphodiesterase 6 inhibition by the C-terminal region of the γ-subunit

The inhibitory interaction of phosphodiesterase-6 (PDE6) with its γ-subunit (Pγ) is pivotal in vertebrate phototransduction. Here, crystal structures of a chimaeric PDE5/PDE6 catalytic domain (PDE5/6cd) complexed with sildenafil or 3-isobutyl-1-methylxanthine and the Pγ-inhibitory peptide Pγ70−87 have been determined at 2.9 and 3.0 Å, respectively. These structures show the determinants and the mechanism of the PDE6 inhibition by Pγ and suggest the conformational change of Pγ on transducin activation. Two variable H- and M-loops of PDE5/6cd form a distinct interface that contributes to the Pγ-binding site. This allows the Pγ C-terminus to fit into the opening of the catalytic pocket, blocking cGMP access to the active site. Our analysis suggests that disruption of the H–M loop interface and Pγ-binding site is a molecular cause of retinal degeneration in atrd3 mice. Comparison of the two PDE5/6cd structures shows an overlap between the sildenafil and Pγ70−87-binding sites, thereby providing critical insights into the side effects of PDE5 inhibitors on vision

Fields on fire: Alternatives to crop residue burning in India.

Farmer profit can be increased and air quality improve