KINETIC EFFECT OF A FOUR-STEP AND STEP-CLOSE APPROACH IN A VOLLEYBALL SPIKE JUMP FOR FEMALE ATHLETES

The purpose of the present study was to investigate the kinetic difference between two different volleyball spike jump techniques: a complete four-step approach and step-close approach. Five female collegiate volleyball players (age: 20.40 ± 1.85, height: 1.80 ± 0.02 m, body weight: 71.71 ± 4.18 kg) who play the middle hitter position were recruited. Each participant performed ten jumps for both four-step and step-close approaches and takeoff from two Kistler force platforms. Results indicated that there is no significant difference (P = .18) of vertical propulsive impulse between the two types of jump. The anterior-posterior (AP) net impulse of the four-step approach was significantly greater than a step-close approach (P < .01). Finally, the contact duration of propulsive phase for step-close technique is significantly greater than four-step approach technique (P < .05)

Prion‐like proteins: from computational approaches to proteome‐wide analysis

Altres ajuts: ICREA-Academia 2020Prions are self-perpetuating proteins able to switch between a soluble state and an aggregated-and-transmissible conformation. These proteinaceous entities have been widely studied in yeast, where they are involved in hereditable phenotypic adaptations. The notion that such proteins could play functional roles and be positively selected by evolution has triggered the development of computational tools to identify prion-like proteins in different kingdoms of life. These algorithms have succeeded in screening multiple proteomes, allowing the identification of prion-like proteins in a diversity of unrelated organisms, evidencing that the prion phenomenon is well conserved among species. Interestingly enough, prion-like proteins are not only connected with the formation of functional membraneless protein-nucleic acid coacervates, but are also linked to human diseases. This review addresses state-of-the-art computational approaches to identify prion-like proteins, describes proteome-wide analysis efforts, discusses these unique proteins' functional role, and illustrates recently validated examples in different domains of life

Distinct Prion Domain Sequences Ensure Efficient Amyloid Propagation by Promoting Chaperone Binding or Processing <i>In Vivo</i>

<div><p>Prions are a group of proteins that can adopt a spectrum of metastable conformations <i>in vivo</i>. These alternative states change protein function and are self-replicating and transmissible, creating protein-based elements of inheritance and infectivity. Prion conformational flexibility is encoded in the amino acid composition and sequence of the protein, which dictate its ability not only to form an ordered aggregate known as amyloid but also to maintain and transmit this structure <i>in vivo</i>. But, while we can effectively predict amyloid propensity <i>in vitro</i>, the mechanism by which sequence elements promote prion propagation <i>in vivo</i> remains unclear. In yeast, propagation of the [<i>PSI</i>^<i>+</i>] prion, the amyloid form of the Sup35 protein, has been linked to an oligopeptide repeat region of the protein. Here, we demonstrate that this region is composed of separable functional elements, the repeats themselves and a repeat proximal region, which are both required for efficient prion propagation. Changes in the numbers of these elements do not alter the physical properties of Sup35 amyloid, but their presence promotes amyloid fragmentation, and therefore maintenance, by molecular chaperones. Rather than acting redundantly, our observations suggest that these sequence elements make complementary contributions to prion propagation, with the repeat proximal region promoting chaperone binding to and the repeats promoting chaperone processing of Sup35 amyloid.</p></div