La situación de crisis económica que atraviesa España desde hace másde un lustro está infl uyendo en las formas de relación de la ciudadaníacon el consumo, no solo en términos de gasto económico sino ...de unarefl exión más profunda sobre el propio concepto de consumir. Esteartículo tiene como objetivo explorar los discursos sociales másrecientes sobre el consumo en España, basándose en los resultados deuna investigación empírica de carácter cualitativo. Para ello, se analizany discuten los materiales recogidos a partir de la realización de variosgrupos de discusión durante el primer trimestre de 2014. Los resultadosmuestran no solamente la generalización de prácticas de consumo másausteras, sino una crítica a la idea de que «hemos vivido por encima denuestras posibilidades».
Mechanical Deformation Accelerates Protein Ageing Valle‐Orero, Jessica; Rivas‐Pardo, Jaime Andrés; Tapia‐Rojo, Rafael ...
Angewandte Chemie,
August 7, 2017, Letnik:
56, Številka:
33
Journal Article
Recenzirano
Odprti dostop
A hallmark of tissue ageing is the irreversible oxidative modification of its proteins. We show that single proteins, kept unfolded and extended by a mechanical force, undergo accelerated ageing in ...times scales of minutes to days. A protein forced to be continuously unfolded completely loses its ability to contract by folding, becoming a labile polymer. Ageing rates vary among different proteins, but in all cases they lose their mechanical integrity. Random oxidative modification of cryptic side chains exposed by mechanical unfolding can be slowed by the addition of antioxidants such as ascorbic acid, or accelerated by oxidants. By contrast, proteins kept in the folded state and probed over week‐long experiments show greatly reduced rates of ageing. We demonstrate a novel approach whereby protein ageing can be greatly accelerated: the constant unfolding of a protein for hours to days is equivalent to decades of exposure to free radicals under physiological conditions.
Time will tell: Accelerated ageing occurs when a protein is held unfolded under force for long periods of time. Maintaining a protein extended for more than 20 h blocks its ability to refold. This loss of folding contraction is triggered by the exposure of cryptic side chains to the oxidative environment, and can be greatly slowed by antioxidants. This kind of oxidative damage is a hallmark of the loss of tissue elasticity that occurs during ageing.
The economic crisis that Spain has been facing since 2008 has produced significant effects in the way citizens are dealing with consumption. Beyond austerity practices and concerns about an uncertain ...future, there is a rising anxiety about the sustainability of current consumption patterns. Moreover, it is interesting to analyse how consumption evolves in a situation in which the budget is highly constrained. How do people from different social classes perceive consumption under these circumstances? Our contribution deals with those issues using data from a focus groups based research project whose main goal was to map necessities and consumption practices in Spain, trying to assess the impact of the crisis. In this article we will discuss the results focusing on how different groups of interviewees elaborate a discourse about it which ranges from guilt to a strong moral discourse related to the adequate level of consumption. We consider that this paper might provide a deeper knowledge of the relationship between consumption and social class in a context of financial and economic crisis.
Single-molecule atomic force microscopy and magnetic tweezers experiments have demonstrated that titin immunoglobulin (Ig) domains are capable of folding against a pulling force, generating ...mechanical work that exceeds that produced by a myosin motor. We hypothesize that upon muscle activation, formation of actomyosin cross bridges reduces the force on titin, causing entropic recoil of the titin polymer and triggering the folding of the titin Ig domains. In the physiological force range of 4-15 pN under which titin operates in muscle, the folding contraction of a single Ig domain can generate 200% of the work of entropic recoil and occurs at forces that exceed the maximum stalling force of single myosin motors. Thus, titin operates like a mechanical battery, storing elastic energy efficiently by unfolding Ig domains and delivering the charge back by folding when the motors are activated during a contraction. We advance the hypothesis that titin folding and myosin activation act as inextricable partners during muscle contraction.
Mechanical forces are critical to protein function across many biological contexts-from bacterial adhesion to muscle mechanics and mechanotransduction processes. Hence, understanding how mechanical ...forces govern protein activity has developed into a central scientific question. In this context, single-molecule magnetic tweezers has recently emerged as a valuable experimental tool, offering the capability to measure single proteins over physiologically relevant forces and timescales. In this chapter, we present a detailed protocol for the assembly and operation of our magnetic tape head tweezers instrument, specifically tailored to investigate protein dynamics. Our instrument boasts a simplified microscope design and incorporates a magnetic tape head as the force-generating apparatus, facilitating precise force control and enhancing its temporal stability, enabling the study of single protein mechanics over extended timescales spanning several hours or even days. Moreover, its straightforward and cost-effective design ensures its accessibility to the wider scientific community. We anticipate that this technique will attract widespread interest within the growing field of mechanobiology and expect that this chapter will provide facilitated accessibility to this technology.
Allosteric activation of vinculin by talin Franz, Florian; Tapia-Rojo, Rafael; Winograd-Katz, Sabina ...
Nature communications,
07/2023, Letnik:
14, Številka:
1
Journal Article
Recenzirano
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The talin-vinculin axis is a key mechanosensing component of cellular focal adhesions. How talin and vinculin respond to forces and regulate one another remains unclear. By combining single-molecule ...magnetic tweezers experiments, Molecular Dynamics simulations, actin-bundling assays, and adhesion assembly experiments in live cells, we here describe a two-ways allosteric network within vinculin as a regulator of the talin-vinculin interaction. We directly observe a maturation process of vinculin upon talin binding, which reinforces the binding to talin at a rate of 0.03 s
. This allosteric transition can compete with force-induced dissociation of vinculin from talin only at forces up to 10 pN. Mimicking the allosteric activation by mutation yields a vinculin molecule that bundles actin and localizes to focal adhesions in a force-independent manner. Hence, the allosteric switch confines talin-vinculin interactions and focal adhesion build-up to intermediate force levels. The 'allosteric vinculin mutant' is a valuable molecular tool to further dissect the mechanical and biochemical signalling circuits at focal adhesions and elsewhere.
The aim of this article is to explore social discourses in Spain on the economic crisis under the scenario of austerity policies and cutbacks. The goal is to explore whether social perceptions have ...changed throughout the crisis that evolved from the collapse of the housing market bubble to a public deficit and debt problem, leading to record rates of unemployment and a dramatic decline in living standards. The long crisis has left an imprint on Spanish society and it is worthwhile exploring how Spanish citizens reflect upon the crisis. To do so, 18 focus groups were organized in two rounds (2010 and 2014) and the results of those group conversations are discussed and compared here. The analysis shows that the participants elaborated not only on reflections about the crisis and on how it has lowered their consumption levels, but also on their further views about the social structure and change. The notorious pessimism of Spaniards about their future, regardless of their class position, is highlighted in the results. A more critical narrative about the crisis seemed to emerge in 2014, leaving behind the guilt‐laden “living beyond our means” discourses that dominated in 2010.
Proteins fold under mechanical forces in a number of biological processes, ranging from muscle contraction to co-translational folding. As force hinders the folding transition, chaperones must play a ...role in this scenario, although their influence on protein folding under force has not been directly monitored yet. Here, we introduce single-molecule magnetic tweezers to study the folding dynamics of protein L in presence of the prototypical molecular chaperone trigger factor over the range of physiological forces (4-10 pN). Our results show that trigger factor increases prominently the probability of folding against force and accelerates the refolding kinetics. Moreover, we find that trigger factor catalyzes the folding reaction in a force-dependent manner; as the force increases, higher concentrations of trigger factor are needed to rescue folding. We propose that chaperones such as trigger factor can work as foldases under force, a mechanism which could be of relevance for several physiological processes.Proteins fold under mechanical force during co-translational folding at the ribosome. Here, the authors use single molecule magnetic tweezers to study the influence of chaperones on protein folding and show that the ribosomal chaperone trigger factor acts as a mechanical foldase by promoting protein folding under force.
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