Valoración económica de los beneficios ambientales de la recuperación del río segura (España)

La Directiva Marco del Agua de la Unión Europea establece la necesidad de alcanzar el buen estadoecológico de las masas de agua para el año 2015. Esto requiere la aplicación de diferentes medidas, entrelas que destacan los planes de restauración ambiental de ríos. Además, esta Directiva integra el usode instrumentos económicos para justificar aquellas medidas diseñadas para conseguir el buen estadode una masa de agua. Este trabajo tiene como objetivo valorar en términos monetarios los beneficiosambientales de la recuperación ambiental de un ecosistema natural, el río Segura, mediante el método devaloración contingente. Los resultados muestran que los beneficios generados por el río tras su recuperaciónascenderían a los siete millones de euros anuales. Este valor debería ser considerado en los análisiscosto - beneficio de las actuaciones emprendidas en el río Segura con el fin de justificar su rentabilidadsocial desde una óptica económica

De novo reconstitution reveals the proteins required for skeletal muscle voltage-induced Ca2+ release

Skeletal muscle contraction is triggered by Ca2+ release from the sarcoplasmic reticulum (SR) in response to plasma membrane (PM) excitation. In vertebrates, this depends on activation of the RyR1 Ca2+ pore in the SR, under control of conformational changes of CaV1.1, located ∼12 nm away in the PM. Over the last ∼30 y, gene knockouts have revealed that CaV1.1/RyR1 coupling requires additional proteins, but leave open the possibility that currently untested proteins are also necessary. Here, we demonstrate the reconstitution of conformational coupling in tsA201 cells by expression of CaV1.1, β1a, Stac3, RyR1, and junctophilin2. As in muscle, depolarization evokes Ca2+ transients independent of external Ca2+ entry and having amplitude with a saturating dependence on voltage. Moreover, freeze-fracture electron microscopy indicates that the five identified proteins are sufficient to establish physical links between CaV1.1 and RyR1. Thus, these proteins constitute the key elements essential for excitation-contraction coupling in skeletal muscle

Novel Details of Calsequestrin Gel Conformation in Situ

Calsequestrin (CASQ) is the major component of the sarcoplasmic reticulum (SR) lumen in skeletal and cardiac muscles. This calcium-binding protein localizes to the junctional SR (jSR) cisternae, where it is responsible for the storage of large amounts of Ca2+, whereas it is usually absent, at least in its polymerized form, in the free SR. The retention of CASQ inside the jSR is due partly to its association with other jSR proteins, such as junctin and triadin, and partly to its ability to polymerize, in a high Ca2+ environment, into an intricate gel that holds the protein in place. In this work, we shed some light on the still poorly described in situ structure of polymerized CASQ using detailed EM images from thin sections, with and without tilting, and from deep-etched rotary-shadowed replicas. The latter directly illustrate the fundamental network nature of polymerized CASQ, revealing repeated nodal points connecting short segments of the linear polymer. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc. Published in the U.S.A

Highly extensible skeletal muscle in snakes

Many snakes swallow large prey whole, and this process requires large displacements of the unfused tips of the mandibles and passive stretching of the soft tissues connecting them. Under these conditions, the intermandibular muscles are highly stretched but subsequently recover normal function. In the highly stretched condition we observed in snakes, sarcomere length (SL) increased 210% its resting value (SL0), and actin and myosin filaments no longer overlapped. Myofibrils fell out of register and triad alignment was disrupted. Following passive recovery, SLs returned to 82% SL0, creating a region of double-overlapping actin filaments. Recovery required recoil of intracellular titin filaments, elastic cytoskeletal components for realigning myofibrils, and muscle activation. Stretch of whole muscles exceeded that of sarcomeres as a result of extension of folded terminal tendon fibrils, stretching of extracellular elastin and independent slippage of muscle fibers. Snake intermandibular muscles thus provide a unique model of how basic components of vertebrate skeletal muscle can be modified to permit extreme extensibility. © 2014. Published by The Company of Biologists Ltd

Efficacy of a novel light-activated antimicrobial coating for disinfecting hospital surfaces.

Silicone polymers containing the light-activated antimicrobial agent methylene blue with or without gold nanoparticles were evaluated for their ability to reduce the microbial load on surfaces in a clinical environment. When irradiated with white light, polymers containing nanogold were more effective in this respect than those containing only methylene blue

Efficacy of a novel light-activated antimicrobial coating for disinfecting hospital surfaces.

Silicone polymers containing the light-activated antimicrobial agent methylene blue with or without gold nanoparticles were evaluated for their ability to reduce the microbial load on surfaces in a clinical environment. When irradiated with white light, polymers containing nanogold were more effective in this respect than those containing only methylene blue

Structural and functional properties of ryanodine receptor type 3 in zebrafish tail muscle

The ryanodine receptor (RyR)1 isoform of the sarcoplasmic reticulum (SR) Ca2++ release channel is an essential component of all skeletal muscle fibers. RyR1s are detectable as "junctional feet" (JF) in the gap between the SR and the plasmalemma or T-tubules, and they are required for excitation-contraction (EC) coupling and differentiation. A second isoform, RyR3, does not sustain EC coupling and differentiation in the absence of RyR1 and is expressed at highly variable levels. Anatomically, RyR3 expression correlates with the presence of parajunctional feet (PJF), which are located on the sides of the SR junctional cisternae in an arrangement found only in fibers expressing RyR3. In frog muscle fibers, the presence of RyR3 and PJF correlates with the occurrence of Ca2++ sparks, which are elementary SR Ca2++ release events of the EC coupling machinery. Here, we explored the structural and functional roles of RyR3 by injecting zebrafish (Danio rerio) one-cell stage embryos with a morpholino designed to specifically silence RyR3 expression. In zebrafish larvae at 72 h postfertilization, fast-twitch fibers from wild-type (WT) tail muscles had abundant PJF. Silencing resulted in a drop of the PJF/JF ratio, from 0.79 in WT fibers to 0.03 in the morphants. The frequency with which Ca2++ sparks were detected dropped correspondingly, from 0.083 to 0.001 sarcomere-1 s-1. The few Ca2++ sparks detected in morphant fibers were smaller in amplitude, duration, and spatial extent compared with those in WT fibers. Despite the almost complete disappearance of PJF and Ca2++ sparks in morphant fibers, these fibers looked structurally normal and the swimming behavior of the larvae was not affected. This paper provides important evidence that RyR3 is the main constituent of the PJF and is the main contributor to the SR Ca2++ flux underlying Ca2++ sparks detected in fully differentiated frog and fish fibers. © 2015 Perni et al

Evidence for Altered Ca2+ Handling in Growth Associated Protein 43-Knockout Skeletal Muscle

Neuronal growth-associated protein 43 (GAP43) has crucial roles in the nervous system, and during development, regeneration after injury, and learning and memory. GAP43 is expressed in mouse skeletal muscle fibers and satellite cells, with suggested its involvement in intracellular Ca2+ handling. However, the physiological role of GAP43 in muscle remains unknown. Using a GAP43-knockout (GAP43-/-) mouse, we have defined the role of GAP43 in skeletal muscle. GAP43-/- mice showed low survival beyond weaning, reduced adult body weight, decreased muscle strength, and changed myofiber ultrastructure, with no significant differences in the expression of markers of satellite cell and myotube progression through the myogenic program. Thus, GAP43 expression is involved in timing of muscle maturation in-vivo. Intracellular Ca2+ measurements in-vitro in myotubes revealed GAP43 involvement in Ca2+ handling. In the absence of GAP43 expression, the spontaneous Ca2+ variations had greater amplitudes and higher frequency. In GAP43-/- myotubes, also the intracellular Ca2+ variations induced by the activation of dihydropyridine and ryanodine Ca2++ channels, resulted modified. These evidences suggested dysregulation of Ca2+ homeostasis. The emerging hypothesis indicates that GAP43 interacts with calmodulin to indirectly modulate the activities of dihydropyridine and ryanodine Ca2+ channels. This thus influences intracellular Ca2+ dynamics and its related intracellular patterns, from functional excitation-contraction coupling, to cell metabolism, and gene expression. © 2016 Caprara, Morabito, Perni, Navarra, Guarnieri and Mariggiò

Valoración económica de los beneficios ambientales de la recuperación del río segura (España)

La Directiva Marco del Agua de la Unión Europea establece la necesidad de alcanzar el buen estadoecológico de las masas de agua para el año 2015. Esto requiere la aplicación de diferentes medidas, entrelas que destacan los planes de restauración ambiental de ríos. Además, esta Directiva integra el usode instrumentos económicos para justificar aquellas medidas diseñadas para conseguir el buen estadode una masa de agua. Este trabajo tiene como objetivo valorar en términos monetarios los beneficiosambientales de la recuperación ambiental de un ecosistema natural, el río Segura, mediante el método devaloración contingente. Los resultados muestran que los beneficios generados por el río tras su recuperaciónascenderían a los siete millones de euros anuales. Este valor debería ser considerado en los análisiscosto - beneficio de las actuaciones emprendidas en el río Segura con el fin de justificar su rentabilidadsocial desde una óptica económica

Nanoscale patterning of STIM1 and Orai1 during store-operated Ca2+ entry

Stromal interacting molecule (STIM) and Orai proteins constitute the core machinery of store-operated calcium entry. We used transmission and freeze-fracture electron microscopy to visualize STIM1 and Orai1 at endoplasmic reticulum (ER)-plasma membrane (PM) junctions in HEK 293 cells. Compared with control cells, thin sections of STIM1-transfected cells possessed far more ER elements, which took the form of complex stackable cisternae and labyrinthine structures adjoining the PM at junctional couplings (JCs). JC formation required STIM1 expression but not store depletion, induced here by thapsigargin (TG). Extended molecules, indicative of STIM1, decorated the cytoplasmic surface of ER, bridged a 12-nm ER-PM gap, and showed clear rearrangement into small clusters following TG treatment. Freeze-fracture replicas of the PM of Orai1-transfected cells showed extensive domains packed with characteristic "particles"; TG treatment led to aggregation of these particles into sharply delimited "puncta" positioned upon raised membrane subdomains. The size and spacing of Orai1 channels were consistent with the Orai crystal structure, and stoichiometry was unchanged by store depletion, coexpression with STIM1, or an Orai1 mutation (L273D) affecting STIM1 association. Although the arrangement of Orai1 channels in puncta was substantially unstructured, a portion of channels were spaced at ?15 nm. Monte Carlo analysis supported a nonrandom distribution for a portion of channels spaced at ∼15 nm. These images offer dramatic, direct views of STIM1 aggregation and Orai1 clustering in store-depleted cells and provide evidence for the interaction of a single Orai1 channel with small clusters of STIM1 molecules