Glutathione participates in the modulation of starvation-induced autophagy in carcinoma cells

Glutathione (γ-L-glutamyl-L-cysteinyl-glycine, GSH) is the most abundant low molecular weight, thiol-containing compound within the cells and has a primary role in the antioxidant defense and intracellular signaling. Here we demonstrated that nutrient deprivation led to a significant decrease of intracellular GSH levels in three different carcinoma cell lines. This phenomenon was dependent on ABCC1-mediated GSH extrusion, along with GCL inhibition and, to a minor extent, the formation of GSH-protein mixed disulfides that synergistically contributed to the modulation of autophagy by shifting the intracellular redox state toward more oxidizing conditions. Modulation of intracellular GSH by inhibiting its de novo synthesis through incubation with buthionine sulfoximine, or by maintaining its levels through GSH ethyl ester, affected the oxidation of protein thiols, such as PRDXs and consequently the kinetics of autophagy activation. We also demonstrated that thiol-oxidizing or -alkylating agents, such as diamide and diethyl maleate activated autophagy, corroborating the evidence that changes in thiol redox state contributed to the occurrence of autophagy

Progressive emergence of double porosity in a silt during compaction

The paper deals with an experimental investigation of water retention properties of a statically compacted unsaturated low plasticity silt. The objective is a deeper understanding of the evolution of an aggregate type fabric at different initial conditions in terms of void ratio and water content. A series of Mercury Intrusion Porosimetry tests (MIP) were performed to provide information about factors influencing fabric changes (effect of mechanical stress due to sample compaction) and fabric-properties relationships (water re-tention curve related to porosimetry). The arrangements of aggregation/particles are also investigated with Environmental Scanning Electron Microscopy (ESEM). The experimental data has been used to calibrate a multimodal water retention model for aggregate which is obtained by linear superposition of sub-curves of the van Genuchten type modified. By comparing the WRC obtained by MIP and under suction controlled conditions it has been found a good agreement between the two method for the drying path

Feasibility study and design of a low-energy residential unit in Sagarmatha park for environmental impact reduction of high altitude buildings

The project presented in this paper is geographically set within Sagarmatha National Park, a wide area located on the Nepalese mountainside of Everest and declared as World Heritage Site since 1979. In recent years the park was the focus of several studies and initiatives, aimed at improving the management of its many-sided ecosystem, significantly influenced by climate change and increase of human activities and tourism, which occurred from the end of the 1970s, as well as by practices that are harmful both to human health and to our environment (e.g. burn up kerosene or animal excrements in order to obtain heat). Research work has focused on designing a residential unit that meets population needs, in terms of simplicity of realization, replicability, use of local materials, environmental compatibility and exploitation of available renewable energies. For this purpose a thorough analysis was conducted to identify the housing standard characteristic of reference context and Sherpa people, concerning indoor thermal comfort conditions, construction techniques, availability and skills of local workforce. Data necessary for the design phase were obtained through a collaboration with researchers of Ev-K2-CNR center, active at 5,050 meters a.s.l. in Nepal at the base of Mount Everest with a laboratory/observatory (known as the "Pyramid") for highaltitude meteorological studies since 1989. Climate conditions were registered by specific monitoring stations at certain times (2002-2008); during preliminary stage, these values were considered representative of the local context chosen for the project, that is Namche Bazar, a village located within the park, in a central point both from the logistic and altimetric/weather points of view. For the residential unit under investigation, two different constructive approaches were selected and compared: earthbags and straw bales. Both techniques have several advantages, in particular availability of raw material (jute bags, soil, straw), simplicity (e.g. earthbag constructions are realized using the ancient technique of pisé, combined with flexible bags or tubes), durability, insulation performance, costeffectiveness. Through a specific software for calculation of winter/summer thermal loads, different combinations of selections of structure and insulation were examined for both solutions, in order to achieve the optimum for the case study. Furthermore on the base of data monitored on site, a specific assessment was carried out to evaluate the potential of solar and wind resources. Aiming at entirely covering the heat and electric energy needs by exploiting renewable energy sources, various plant configurations were finally assumed. Every single choice was made to reduce human influence on land resources, such as timber, and to improve internal and external environmental quality

Under the ROS…thiol network is the principal suspect for autophagy commitment.

Low molecular weight and protein sulphydryls undergo reactive oxygen species (ROS)-mediated oxidation. However, in contrast to the irreversible damages that oxidative conditions yield on biomolecules, the oxidation of reactive cysteines frequently results in reversible modifications, which represent the prototype of the molecular mechanisms underlying redox signaling. Many proteins involved in a wide range of cellular processes have been classified as “redoxsensitive,” thereby modulating their function/activity dependent on the redox state of their critical thiols. Growing evidence from the past few years supports the idea that ROS production also correlates with the occurrence of autophagy. Nonetheless, the cysteine protease Atg4 remains the sole example of a protein whose redox regulation has been completely characterized and demonstrated to be necessary for the progression of autophagy. The principal aim of this commentary is to draw attention to the remarkable number of proteins that can fit the double role of: (i) being involved in autophagy, especially in autophagosome formation and (ii) sensing alterations of the cellular redox state by means of reactive cysteine residues. We will also attempt to provide a hypothetical model to explain the possible functional role of thiols in the occurrence of autophagy and outline a network of redox reactions likely concurring to allow the correct initiation and completion of autophagosomes

Life cycle assessment of synthetic natural gas production from different CO2 sources: A cradle⇂to-gate study

Fuel production from hydrogen and carbon dioxide is considered an attractive solution as long‐term storage of electric energy and as temporary storage of carbon dioxide. A large variety of CO2 sources are suitable for Carbon Capture Utilization (CCU), and the process energy intensity depends on the separation technology and, ultimately, on the CO2 concentration in the flue gas. Since the carbon capture process emits more CO2 than the expected demand for CO2 utilization, the most sustainable CO2 sources must be selected. This work aimed at modeling a Power‐to‐Gas (PtG) plant and assessing the most suitable carbon sources from a Life Cycle Assessment (LCA) perspective. The PtG plant was supplied by electricity from a 2030 scenario for Italian electricity generation. The plant impacts were assessed using data from the ecoinvent database version 3.5, for different CO2 sources (e.g., air, cement, iron, and steel plants). A detailed discussion on how to handle multi‐functionality was also carried out. The results showed that capturing CO2 from hydrogen production plants and integrated pulp and paper mills led to the lowest impacts concerning all investigated indicators. The choice of how to handle multi‐functional activities had a crucial impact on the assessment

Multi-objective optimization of CCHP system with hybrid chiller under new electric load following operation strategy

The performance of combined cooling, heating and power (CCHP) system is greatly affected by its operating strategy and design. In this paper, a new electric load following (NELF) strategy was developed. It is based on the alternation between absorption cooling and electric cooling according to the building energy requirements, for hybrid chiller based CCHP systems. A comparison of the new proposed strategy with the modified electric load following (MELF) and electric load following (ELF) strategies is performed. A multi-objective optimization approach based on genetic algorithm is carried out to predict the optimal capacity of CCHP systems. Performance criteria like primary energy consumption, annual total cost and carbon dioxide emission were considered as objective functions. The performances of these CCHP systems and operation strategies were examined and compared with the separated production (SP) system for a Mosque complex located in Algiers, Algeria. Results show that hybrid chiller CCHP based NELF strategy is the best choice, which can reduce the primary energy consumption by 34.45 GWh/year, annual total cost by 0.313 million €/year and carbon dioxide emission by 8.37 kton/year. Compared to the other configurations and strategies, the hybrid CCHP based NELF achieves better energetic, economic and environmental performance under the optimized conditions

Iron entry route in horse spleen apoferritin Involvement of the three-fold channels as probed by selective reaction of cysteine-126 with the spin label 4-maleimido-tempo

AbstractApoferritin has been selectively labeled with a maleimide nitroxide derivative at Cys-126, located in the hydrophilic 3-fold channels. Titration of this derivative with Fe(II), which gives rise to the initial Fe(III)-apoferritin complex, produces, at low metal-to-protein ratios, a decrease of the intensity of the label EPR signal due to the occurrence of a magnetic dipolar interaction. A label-metal distance ranging between 8–12 Å can be estimated from titrations performed with VO(IV), which is known to bind in the 3-fold channels, and likewise produces a decrease in the label EPR signal. The present findings indicate that iron binds in the hydrophilic channels in its higher oxidation slate and that these channels represent the metal entry route at least at low metal-to-protein ratios

Carcinoma cells activate AMP-activated protein kinase-dependent autophagy as survival response to kaempferol-mediated energetic impairment.

Kaempferol, a dietary cancer chemopreventive polyphenol, has been reported to trigger apoptosis in several tumor histotypes, but the mechanism underlying this phenomenon is not fully understood. Here, we demonstrate that in HeLa cells, kaempferol induces energetic failure due to inhibition of both glucose uptake and Complex I of the mitochondrial respiratory chain. As adaptive response, cells activate autophagy, the occurrence of which was established cytofluorometrically, upon acridine orange staining, and immunochemically, by following the increase of the autolysosome-associated form of the microtubule-associated protein light chain 3 (LC3-II). Autophagy is an early and reversible process occurring as survival mechanisms against apoptosis. Indeed, chemical inhibition of autophagy, by incubations with monensin, wortmannin, 3-methyladenine, or by silencing Atg5, significantly increases the extent of apoptosis, which takes place via the mitochondrial pathway, and shortens the time in which the apoptotic markers are detectable. We also demonstrate that autophagy depends on the early activation of the AMP-activated protein kinase (AMPK)/mTOR-mediated pathway. The overexpression of dominant negative AMPK results in a decrease of autophagic cells, a decrement of LC3-II levels, and a significant increase of apoptosis. Experiments performed with another carcinoma cell line yielded the same results, suggesting for kaempferol a unique mechanism of action