LETM1-Mediated K+ and Na+ Homeostasis Regulates Mitochondrial Ca2+ Efflux

HIGHLIGHTS \u2022 Monovalent cation homeostasis is dysregulated upon LETM1 depletion \u2022 K+/H+ exchange activity is decreased in LETM1 knockdown cells \u2022 LETM1 depletion results in K+ accumulation in the mitochondrial matrix \u2022 LETM1 knockdown does not affect expression of major mitochondrial Ca2+ transport modulators \u2022 LETM1-regulated mitochondrial Ca2+ fluxes are dependent on Na+ Ca2+ transport across the inner membrane of mitochondria (IMM) is of major importance for their functions in bioenergetics, cell death and signaling. It is therefore tightly regulated. It has been recently proposed that LETM1\u2014an IMM protein with a crucial role in mitochondrial K+/H+ exchange and volume homeostasis\u2014also acts as a Ca2+/H+ exchanger. Here we show for the first time that lowering LETM1 gene expression by shRNA hampers mitochondrial K+/H+ and Na+/H+ exchange. Decreased exchange activity resulted in matrix K+ accumulation in these mitochondria. Furthermore, LETM1 depletion selectively decreased Na+/Ca2+ exchange mediated by NCLX, as observed in the presence of ruthenium red, a blocker of the Mitochondrial Ca2+ Uniporter (MCU). These data confirm a key role of LETM1 in monovalent cation homeostasis, and suggest that the effects of its modulation on mitochondrial transmembrane Ca2+ fluxes may reflect those on Na+/H+ exchange activity

Modulation of the mitochondrial megachannel by divalent cations and protons.

In patch-clamp experiments on rat liver mitoplasts, the 1.3 nanosiemens (in 150 mM KCl) mitochondrial megachannel was activated by Ca2+ and competitively inhibited by Mg2+, Mn2+, Ba2+, and Sr2+. Cyclosporin A, which inhibits the megachannel, also showed a competitive behavior versus Ca2+. The pore is regulated by pH in the physiological range; lower pH values cause its closure in a Ca(2+)-reversible manner. The modulating sites involved in these effects are located on the matrix side of the membrane. As illustrated in the companion paper (Bernardi, P., Vassanelli, S., Veronese, P., Colonna, R., Szabó, I., and Zoratti, M. (1992) J. Biol. Chem. 267, 2934-2939), the calcium-induced permeability transition of mitochondria is affected by these various agents in a similar manner. The results support the identification of the megachannel with the pore believed to be involved in the permeabilization process. The kinetic characteristics of the single channel events support the idea that the megachannel is composed of cooperating subunits

Applications of model-aware reinforcement learning in Bayesian quantum metrology

An important practical problem in the field of quantum metrology and sensors is to find the optimal sequences of controls for the quantum probe that realize optimal adaptive estimation. In Belliardo et al., arXiv:2312.16985 (2023), we solved this problem in general, by introducing a procedure capable of optimizing a wide range of tasks in quantum metrology and estimation by combining model-aware reinforcement learning with Bayesian inference. We take a model-based approach to the optimisation where the physics describing the system is explicitly taken into account in the training through automatic differentiation. In this follow-up paper we present some applications of the framework. The first family of examples concerns the estimation of magnetic fields, hyperfine interactions, and decoherence times for electronic spins in diamond. For these examples, we perform multiple Ramsey measurements on the spin. The second family of applications concerns the estimation of phases and coherent states on photonic circuits, without squeezing elements, where the bosonic lines are measured by photon counters. This exposition showcases the broad applicability of the method, which has been implemented in the qsensoropt library released on PyPI, which can be installed with pip.Comment: 35 pages, 16 figure

Applications of model-aware reinforcement learning in Bayesian quantum metrology

An important practical problem in the field of quantum metrology and sensors is to find the optimal sequences of controls for the quantum probe that realize optimal adaptive estimation. In Belliardo [arXiv:2312.16985], we solved this problem in general by introducing a procedure capable of optimizing a wide range of tasks in quantum metrology and estimation by combining model-aware reinforcement learning with Bayesian inference. We take a model-based approach to the optimization where the physics describing the system is explicitly taken into account in the training through automatic differentiation. In this follow-up paper we present some applications of the framework. The first family of examples concerns the estimation of magnetic fields, hyperfine interactions, and decoherence times for electronic spins in diamond. For these examples, we perform multiple Ramsey measurements on the spin. The second family of applications concerns the estimation of phases and coherent states on photonic circuits, without squeezing elements, where the bosonic lines are measured by photon counters. This exposition showcases the broad applicability of the method, which has been implemented in the qsensoropt library released on PyPI, which can be installed with pip

Assessing the solid-liquid discharge and rheological behavior of debris flow. A numerical model of a case study

The Friuli Venezia Giulia (FVG) region, located in the northeast of Italy, is characterised by frequent heavy precipitations that recurrently trigger debris flow phenomena. On August 2003, an intense rainfall concentrated in the north-eastern Julian Alps of FVG produced several floods and debris flow events, widespread on the entire basin of the Fella river watershed, with great economic damage and some casualties. In the light of this, forecasting tools for the debris-flow analysis are useful with a view to a territorial planning. The general aim of our research is to develop a hydro-morphodynamical framework to study debris flow phenomena, which includes the hydrological modelling of the rainfall triggering event, the estimate of the solid-liquid discharge of the debris-flow and the hydraulic modelling of its propagation. While previous works have accomplished the hydrological analysis, in the present study we focus on the evaluation of the solid-liquid discharge and the simulation of its propagation down the slope till its stop. Specifically, we considered a sub-basin of the Fella river watershed, the Uque at Ugovizza, and, in particular, a sub-area of the basin from which the debris flow that swept the village of Ugovizza in 2003 came off. The resulting liquid discharge obtained from the previous hydrological analysis was the input data to derive the solid-liquid discharge of the debris flow, which was assessed by using a formulation proposed in literature. In order to study the propagation of the debris flow, we first identified a rheology model suitable to represent this kind of events. This was then implemented into an in-house numerical model, which integrates the bidimensional shallow water equations by means of finite volume techniques. Furthermore, an appropriate runout criterion was also assessed, so that the final stages of the phenomenon can be represented. The first results of the application of the developed hydro-morphodynamic framework to this case study are presented and discussed

Performance evaluation of a tracking system for intermodal traffic: an experimentation in the Tyrrhenian area

Monitoring shipments along intermodal chains is crucial to ensuring the fast, reliable and secure transport of goods. In this regard, the paper describes the results of a real-life tracking experimentation carried out in June 2018 in the Tyrrhenian area with a twofold objective: 1) to evaluate the performance of a state-of-art tracking system to effectively monitor Ro-Ro freight units moving along intermodal chains; 2) to get an objective view of the intermodal chains currently connecting the two main Italian islands to the mainland. The experimentation was performed by means of a tracking device using the GSM network for data connection and geographical position detection. In addition, the Automatic Identification System (AIS) data were used to improve positioning during navigation. Quantitative analyses carried out on the recorded tracking data revealed that a significant share of the total transport time of the monitored transport chains is unproductive time that goods spend waiting at the port and logistics nodes. From a technical point of view, the experimentation raised several problems of the tracking technology employed vis-à-vis real-time tracking, continuous monitoring, signal coverage and positioning accuracy. A discussion of the main detected limitations is provided in the paper along with some possible solutions to overcome them

Modification of sunlight radiation through colored photo-selective nets affects anthocyanin profile in Vaccinium spp. berries

<p>Objectives In recent years, the interest on the effects of the specific wavelengths of the light spectrum on growth and metabolism of plants has been increasing markedly. The present study covers the effect of modified sunlight conditions on the accumulation of anthocyanin pigments in two Vaccinium species: the European wild bilberry (V. myrtillus L.) and the cultivated highbush blueberry (V. corymbosum L.). <p>Methods The two Vaccinium species were grown in the same test field in the Alps of Trentino (Northern Italy) under modified light environment. The modification of sunlight radiation was carried out in field, through the use of colored photo-selective nets throughout the berry ripening during two consecutive growing seasons. The anthocyanin profile was then assessed in berries at ripeness. <p>Results The results indicated that the light responses of the two Vaccinium species studied were different. Although both studied species are shade-adapted plants, 90% shading of sunlight radiation was beneficial only for bilberry plants, which accumulated the highest content of anthocyanins in both seasons. The same condition, instead, was not favorable for blueberries, whose maturation was delayed for at least two weeks, and anthocyanin accumulation was significantly decreased compared to berries grown under sunlight conditions. Moreover, the growing season had strong influence on the anthocyanin accumulation in both species, in relation to temperature flow and sunlight spectra composition during the berry ripening period. <p>Conclusions Our results suggest that the use of colored photo-selective nets may be a complementary agricultural practice for cultivation of Vaccinium species. However, further studies are needed to analyze the effect of the light spectra modifications to other nutritional properties, and to elucidate the molecular mechanisms behind the detected differences between the two relative Vaccinium species

An innovative method for anchoring glucose-sensing molecules on glassy micro-particles

In this work a modified glassy micro-particles glucose sensor was developed applying a new and effective procedure to anchor glucose oxidase on glassy micro particles using urea medium. The resulting sensor, in the presence of glucose, generates a color development in 60 seconds working at room temperature. The intensity of the resulting color shows a straightforward relationship with the glucose concentration in the samples tested. The resulting biosensor was tested to demonstrate its sensibility on dissolutions of glucose and honey.Fil: Zoratti, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Centurión, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Frechero, Marisa Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin