Search

One key question regarding current climate models is whether the projection of climate extremes converges to a realistic representation as the spatial and temporal resolutions of the model are increased. Ideally the model extreme statistics should approach a fixed distribution once the resolutions are commensurate with the characteristic length and time scales of the processes governing the formation of the extreme phenomena of interest. In this study, a series of AGCM runs with idealized 'aquaplanet-steady-state' boundary conditions have been performed with the Community Atmosphere Model CAM3 to investigate the effect of horizontal resolution on climate extreme simulations. The use of the aquaplanet framework highlights the roles of model physics and dynamics and removes any apparent convergence in extreme statistics due to better resolution of surface boundary conditions and other external inputs. Assessed at a same large spatial scale, the results show that the horizontal resolution and time step have strong effects on the simulations of precipitation extremes. The horizontal resolution has a much stronger impact on precipitation extremes than on mean precipitation. Updrafts are strongly correlated with extreme precipitation at tropics at all the resolutions, while positive low-tropospheric temperature anomalies are associated with extreme precipitation at mid-latitudes. © 2011 The Authors Tellus A © 2011 John Wiley & Sons A/S.

Abstract: CO selective oxidation (Selox) for the purification of hydrogen-rich streams was studied in membrane reactors (MRs) using Pt-loaded catalytic membranes. The catalytic membranes were prepared by the ion-exchange of FAU (Na-Y) zeolitic membranes that were synthesized on tubular α-Al2O3 supports by a secondary growth method. The catalytic MR tests were performed analysing the CO conversion, O2 selectivity and yield of the desired reaction. Different feed compositions (CO, O2, H2 and N2 content and O2/CO ratio), temperatures and pressures were considered with space-time values in the range 0.27–1.2mgPt min/cm3(STP). The CO content in preliminary tests was 10%, 1% in the other experiments. A simulated reformate shifted gas mixture (H2 =60%) was also used. A comparison with other literature data for MRs utilizing different membrane types and packed bed traditional reactors with Pt-based catalysts is also provided. The identified ranges of operating conditions (temperature, pressure, feed molar O2/CO ratio and feed concentration) suggest a profitable use of the catalytic MR (Pt-Y zeolite membranes) for CO Selox after the low-temperature water gas shift unit of a fuel processor converting hydrocarbons into hydrogen-rich gas, operating at similar temperature conditions. [Copyright &y& Elsevier]

In this work the effect of two different musical pieces (called “Reminiscenza” and “Pioggia”) on the tyrosinase enzyme activity was investigated. The l-DOPA production by the enzymatic reaction was measured during the continuous playing of these musical pieces. Experiments were performed in the laboratories of the Institute of Membrane Technology (ITM) of the Italian National Council for Research (CNR). The results showed that a positive effect was exercised by the “Reminiscenza” piece, which determined an increase of the specific activity about of 30 % with respect to the value measured in the absence of sound. On the contrary, “Pioggia” piece had a detrimental effect on the enzymatic process. In particular, a time lag on the l-DOPA production, during the first minutes of the reaction, was detected. After this period, an increase of the reaction velocity occurred even if the enzyme activity was lower than the value obtained in the absence of music. These results show that the peculiar characteristics of a musical piece can exercise a positive or negative action on biological elements and open the way to further studies in this area.

We have investigated NADH and succinate aerobic oxidation in frozen and thawed swine heart mitochondria. Simultaneous oxidation of NADH and succinate showed complete additivity under a variety of experimental conditions, suggesting that the electron fluxes originating from NADH and succinate are completely independent and do not mix at the level of the so-called mobile diffusible components. We ascribe the results to mixing of the fluxes at the level of cytochrome c in bovine mitochondria: the Complex IV flux control coefficient in NADH oxidation was high in swine mitochondria but very low in bovine mitochondria, suggesting a stronger interaction of cytochrome c with the supercomplex in the former. This was not the case in succinate oxidation, in which Complex IV exerted little control also in swine mitochondria. We interpret the data in swine mitochondria as restriction of the NADH flux by channelling within the I-III 2 -IV supercomplex, whereas the flux from succinate shows pool mixing for both Coenzyme Q and probably cytochrome c. The difference between the two types of mitochondria may be ascribed to different lipid composition affecting the cytochrome c binding properties, as suggested by breaks in Arrhenius plots of Complex IV activity occurring at higher temperatures in bovine mitochondria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this work, for the first time, the stability of the TiO 2 suspensions used for the photocatalytic membrane preparation was studied by considering the Turbiscan Stability Index (TSI). The use of a stable suspension during the membrane preparation (by the dip-coating method) permitted a better dispersion of the TiO 2 nanoparticles into the membrane structure due to a reduction of agglomerates formation. The dip-coating was performed on the macroporous structure (external surface) of the Al 2 O 3 membrane to avoid large reduction of the permeability. In addition, the reduction of the suspension infiltration along the membrane's cross-section allowed us to preserve the separative layer of the modified membrane. The water flux was reduced by about 11% after the dip-coating. The photocatalytic performance of the prepared membranes was evaluated using the methyl orange as a model pollutant. The reusability of the photocatalytic membranes was also demonstrated.

An efficient, eco-compatible, and very cheap method for the construction of fully substituted pyrazoles (Pzs) via eliminative nitrilimine-alkene 1,3-dipolar cycloaddition (ENAC) reaction was developed in excellent yield and high regioselectivity. Enaminones and nitrilimines generated in situ were selected as dipolarophiles and dipoles, respectively. A deep screening of the employed base, solvent, and temperature was carried out to optimize reaction conditions. Recycling tests of ionic liquid were performed, furnishing efficient performance until six cycles. Finally, a plausible mechanism of cycloaddition was proposed. Then, the effect of three different structures of Pzs was evaluated on the F 1 F O -ATPase activity and mitochondrial permeability transition pore (mPTP) opening. The Pz derivatives' titration curves of 6a , 6h , and 6o on the F 1 F O -ATPase showed a reduced activity of 86%, 35%, and 31%, respectively. Enzyme inhibition analysis depicted an uncompetitive mechanism with the typical formation of the tertiary complex enzyme-substrate-inhibitor ( ESI ). The dissociation constant of the ESI complex ( K i ') in the presence of the 6a had a lower order of magnitude than other Pzs. The pyrazole core might set the specific mechanism of inhibition with the F 1 F O -ATPase, whereas specific functional groups of Pzs might modulate the binding affinity. The mPTP opening decreased in Pz-treated mitochondria and the Pzs' inhibitory effect on the mPTP was concentration-dependent with 6a and 6o . Indeed, the mPTP was more efficiently blocked with 0.1 mM 6a than with 1 mM 6a . On the contrary, 1 mM 6o had stronger desensitization of mPTP formation than 0.1 mM 6o . The F 1 F O -ATPase is a target of Pzs blocking mPTP formation.

The compromised viability and function of cardiovascular cells are rescued by small molecules of triazole derivatives (Tzs), identified as 3a and 3b, by preventing mitochondrial dysfunction. The oxidative phosphorylation improves the respiratory control rate in the presence of Tzs independently of the substrates that energize the mitochondria. The F 1 F O -ATPase, the main candidate in mitochondrial permeability transition pore (mPTP) formation, is the biological target of Tzs and hydrophilic F 1 domain of the enzyme is depicted as the binding region of Tzs. The protective effect of Tz molecules on isolated mitochondria was corroborated by immortalized cardiomyocytes results. Indeed, mPTP opening was attenuated in response to ionomycin. Consequently, increased mitochondrial roundness and reduction of both length and interconnections between mitochondria. In in-vitro and ex-vivo models of cardiovascular pathologies (i.e., hypoxia-reoxygenation and hypertension) were used to evaluate the Tzs cardioprotective action. Key parameters of porcine aortic endothelial cells (pAECs) oxidative metabolism and cell viability were not affected by Tzs. However, in the presence of either 1 μM 3a or 0.5 μM 3b the impaired cell metabolism of pAECs injured by hypoxia-reoxygenation was restored to control respiratory profile. Moreover, endothelial cells isolated from SHRSP exposed to high-salt treatment rescued the Complex I activity and the endothelial capability to form vessel-like tubes and vascular function in presence of Tzs. As a result, the specific biochemical mechanism of Tzs to block Ca 2+ -activated F 1 F O -ATPase protected cell viability and preserved the pAECs bioenergetic metabolism upon hypoxia-reoxygenation injury. Moreover, SHRSP improved vascular dysfunction in response to a high-salt treatment., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Salvatore Nesci reports financial support was provided by University of Bologna. Speranza Rubattu reports financial support was provided by Italian Ministry of Health. Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The beneficial effects of bergamot polyphenolic fraction (BPF) on the mitochondrial bioenergetics of porcine aortic endothelial cells (pAECs) were verified under the cardiotoxic action of doxorubicin (DOX). The cell viability of pAECs treated for 24 h with different concentrations of DOX was reduced by 50%, but the negative effect of DOX was reversed in the presence of increasing doses of BPF (100 µg/mL and 200 µg/mL BPF). An analysis of the protective effect of BPF on the toxic action of DOX was also carried out on cell respiration. We observed the inhibition of the mitochondrial activity at 10 µM DOX, which was not restored by 200 µg/mL BPF. Conversely, the decrease in basal respiration and ATP production caused by 0.5 or 1.0 µM DOX were improved in the presence of 100 or 200 µg/mL BPF, respectively. After 24 h of cell recovery with 100 µg/mL or 200 µg/mL BPF on pAECs treated with 0.5 µM or 1.0 µM DOX, respectively, the mitochondrial parameters of oxidative metabolism impaired by DOX were re-boosted.

LMNA mutation is associated with type-2 familial partial lipodystrophy ( FPLD2 ). The disease causes a disorder characterized by anomalous accumulation of body fat in humans. The dysfunction at the molecular level is triggered by a lamin A/C mutation, impairing the cell metabolism. In human fibroblasts and preadipocytes, a trend for ATP production, mainly supported by mitochondrial oxidative metabolism, is detected. Moreover, primary cell lines with FPLD2 mutation decrease the mitochondrial ATP production if compared with the control , even if no differences are observed in the oxygen consumption rate of bioenergetic parameters (i.e., basal and maximal respiration, spare respiratory capacity, and ATP turnover). Conversely, glycolysis is only inhibited in FPLD2 fibroblast cell lines. We notice that the amount of ATP produced in the fibroblasts is higher than in the preadipocytes, and likewise in the control , with respect to FPLD2 , due to a more active oxidative phosphorylation (OXPHOS) and glycolysis. Moreover, the proton leak parameter, which characterizes the transformation of white adipose tissue to brown/beige adipose tissue, is unaffected by FPLD2 mutation. The metabolic profile of fibroblasts and preadipocytes is confirmed by the ability of these cell lines to increase the metabolic potential of both OXPHOS and glycolysis under energy required independently by the FPLD2 mutation.

The bergamot polyphenolic fraction (BPF) was evaluated in the F 1 F O -ATPase activity of swine heart mitochondria. In the presence of a concentration higher than 50 µg/mL BPF, the ATPase activity of F 1 F O -ATPase, dependent on the natural cofactor Mg 2+ , increased by 15%, whereas the enzyme activity in the presence of Ca 2+ was inhibited by 10%. By considering this opposite BPF effect, the F 1 F O -ATPase activity involved in providing ATP synthesis in oxidative phosphorylation and triggering mitochondrial permeability transition pore (mPTP) formation has been evaluated. The BPF improved the catalytic coupling of oxidative phosphorylation in the presence of a substrate at the first phosphorylation site, boosting the respiratory control ratios (state 3/state 4) by 25% and 85% with 50 µg/mL and 100 µg/mL BPF, respectively. Conversely, the substrate at the second phosphorylation site led to the improvement of the state 3/state 4 ratios by 15% only with 100 µg/mL BPF. Moreover, the BPF carried out its beneficial effect on the mPTP phenomenon by desensitizing the pore opening. The acute effect of the BPF on the metabolism of porcine aortica endothelial cells (pAECs) showed an ATP rate index greater than one, which points out a prevailing mitochondrial oxidative metabolism with respect to the glycolytic pathway, and this ratio rose by about three times with 100 µg/mL BPF. Consistently, the mitochondrial ATP turnover, in addition to the basal and maximal respiration, were higher in the presence of the BPF than in the controls, and the MTT test revealed an increase in cell viability with a BPF concentration above 200 µg/mL. Therefore, the molecule mixture of the BPF aims to ensure good performance of the mitochondrial bioenergetic parameters.

The casting and preparation of ultrafiltration ZnO modified cellulose acetate membrane (CA/ZnO) were investigated in this work. CA membranes were fabricated by phase inversion using dimethylformamide (DMF) as a solvent and ZnO as nanostructures materials. Ultrafiltration (UF) performance, mechanical stability, morphology, contact angle, and porosity were evaluated on both CA- and ZnO-modified CA samples. Scanning electron microscopy (SEM) was used to determine the morphology of the membranes, showing different pore sizes either on rough surfaces and cross-sections of the samples, an asymmetric structure and ultra-scale pores with an average pore radius 0.0261 to 0.045 µm. Contact angle measurements showed the highest hydrophobicity values for the samples with no ZnO addition, ranging between 48° and 82.7° on their airside. The permeability values decreased with the increasing CA concentration in the casting solution, as expected; however, ZnO-modified membranes produced lower flux than the pure CA ones. Nevertheless, ZnO modified CA membranes have higher surface pore size, pore density and porosity, and improved surface hydrophilicity compared with pure CA membranes. The results indicated that the incorporated nano-ZnO tends to limit the packing of the polymer chains onto the membrane structure while showing antifouling properties leading to better hydrophilicity and permeation with consistent UF applications.

The fat-soluble vitamin K (VK) has long been known as a requirement for blood coagulation, but like other vitamins, has been recently recognized to play further physiological roles, particularly in cell development and homeostasis. Vertebrates cannot de novo synthesize VK, which is essential, and it can only be obtained from the diet or by the activity of the gut microbiota. The IPEC-J2 cell line, obtained from porcine small intestine, which shows strong similarities to the human one, represents an excellent functional model to in vitro study the effect of compounds at the intestinal level. The acute VK treatments on the bioenergetic features of IPEC-J2 cells were evaluated by Seahorse XP Agilent technology. VK exists in different structurally related forms (vitamers), all featured by a naphtoquinone moiety, but with distinct effects on IPEC-J2 energy metabolism. The VK1, which has a long hydrocarbon chain, at both concentrations (5 and 10 μM), increases the cellular ATP production due to oxidative phosphorylation (OXPHOS) by 5% and by 30% through glycolysis. The VK2 at 5 μM only stimulates ATP production by OXPHOS. Conversely, 10 μM VK3, which lacks the long side chain, inhibits OXPHOS by 30% and glycolysis by 45%. However, even if IPEC-J2 cells mainly prefer OXPHOS to glycolysis to produce ATP, the OXPHOS/glycolysis ratio significantly decreases in VK1-treated cells, is unaffected by VK2, and only significantly increased by 10 μM VK3. VK1, at the two concentrations tested, does not affect the mitochondrial bioenergetic parameters, while 5 μM VK2 increases and 5 μM VK3 reduces the mitochondrial respiration (i.e., maximal respiration and spare respiratory capacity). Moreover, 10 μM VK3 impairs OXPHOS, as shown by the increase in the proton leak, namely the proton backward entry to the matrix space, thus pointing out mitochondrial toxicity. Furthermore, in the presence of both VK1 and VK2 concentrations, the glycolytic parameters, namely the glycolytic capacity and the glycolytic reserve, are unaltered. In contrast, the inhibition of glycoATP production by VK3 is linked to the 80% inhibition of glycolysis, resulting in a reduced glycolytic capacity and reserve. These data, which demonstrate the VK ability to differently modulate IPEC-J2 cell energy metabolism according to the different structural features of the vitamers, can mirror VK modulatory effects on the cell membrane features and, as a cascade, on the epithelial cell properties and gut functions: balance of salt and water, macromolecule cleavage, detoxification of harmful compounds, and nitrogen recycling., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bernardini, Algieri, La Mantia, Trombetti, Pagliarani, Forni and Nesci.)

Under aerobic conditions, mitochondrial oxidative phosphorylation (OXPHOS) converts the energy released by nutrient oxidation into ATP, the currency of living organisms. The whole biochemical machinery is hosted by the inner mitochondrial membrane (mtIM) where the protonmotive force built by respiratory complexes, dynamically assembled as super-complexes, allows the F 1 F O -ATP synthase to make ATP from ADP + Pi. Recently mitochondria emerged not only as cell powerhouses, but also as signaling hubs by way of reactive oxygen species (ROS) production. However, when ROS removal systems and/or OXPHOS constituents are defective, the physiological ROS generation can cause ROS imbalance and oxidative stress, which in turn damages cell components. Moreover, the morphology of mitochondria rules cell fate and the formation of the mitochondrial permeability transition pore in the mtIM, which, most likely with the F 1 F O -ATP synthase contribution, permeabilizes mitochondria and leads to cell death. As the multiple mitochondrial functions are mutually interconnected, changes in protein composition by mutations or in supercomplex assembly and/or in membrane structures often generate a dysfunctional cascade and lead to life-incompatible diseases or severe syndromes. The known structural/functional changes in mitochondrial proteins and structures, which impact mitochondrial bioenergetics because of an impaired or defective energy transduction system, here reviewed, constitute the main biochemical damage in a variety of genetic and age-related diseases.

Despite the increasing demand of cellular therapies for dogs, little is known on the differences between adult and fetal adnexa canine mesenchymal stem cells (MSCs), and data on their metabolic features are lacking. The present study aimed at comparing the characteristics of canine adipose tissue (AT) and umbilical cord matrix (UC) MSCs. Moreover, for the first time in the dog, the cellular bioenergetics were investigated by evaluating the two main metabolic pathways (oxidative phosphorylation and glycolysis) of ATP production. Frozen-thawed samples were used for this study. No differences in mean cell proliferation were found (P>0.05). However, while AT-MSCs showed a progressive increase in doubling time over passages, UC-MSCs showed an initial post freezing-thawing latency. No differences in migration, spheroid formation ability, and differentiation potential were found (P>0.05). RT-PCR analysis confirmed the expression of CD90 and CD44, the lack of CD14 and weak expression of CD34, mostly by AT-MSCs. DLA-DRA1 and DLA-DQA1 were weakly expressed only at passage 0 by UC-MSCs, while they were expressed at different passages for AT-MSCs. There was no difference (P>0.05) in total ATP production between cell cultures, but the ratio between the "mitochondrial ATP Production Rate" and the "glycolytic ATP Production Rate" was higher (P<0.05) in AT- than in UC-MSCs. However, in both MSCs types the mitochondrial respiration was the main pathway of ATP production. Mitochondrial respiration and ATP turnover in UC-MSCs were higher (P<0.05) than in AT-MSCs, but both had a 100% coupling efficiency. These features and the possibility of increasing the oxygen consumption by a spare respiratory capacity of four (AT-MSCSs) and two (UC-MSCs) order of magnitude greater than basal respiration, can be taken as indicative of the cell propensity to differentiate. The findings may efficiently contribute to select the most appropriate MSCs, culture and experimental conditions for transplantation experiments in mesenchymal stem cell therapy for companion animals., Competing Interests: The authors have declared that no competing interests exist.

Hydrogen sulfide (H 2 S) is now considered not only for its toxicity, but also as an endogenously produced gas transmitter with multiple physiological roles, also in maintaining and regulating stem cell physiology. In the present work, we evaluated the effect of a common H 2 S donor, NaHS, on porcine vascular wall-mesenchymal stem cells (pVW-MSCs). pVW-MSCs were treated for 24 h with increasing doses of NaHS, and the cell viability, cell cycle, and reactive oxygen species (ROS) production were evaluated. Moreover, the long-term effects of NaHS administration on the noteworthy characteristics of pVW-MSCs were analyzed. The MTT test revealed no alteration in cell viability, however, the cell cycle analysis demonstrated that the highest NaHS dose tested (300 μM) determined a block in S phase, which did not depend on the ROS production. Moreover, NaHS (10 μM), continuously administered in culture for 21 days, was able to significantly reduce NG2, Nestin and PDGFR-β expression. The pro-angiogenic attitude of pVW-MSCs was partially reduced by NaHS: the cells maintained the ability to grow in spheroid and sprouting from that, but endothelial markers (Factor VIII and CD31) were reduced. In conclusion, NaHS can be toxic for pVW-MSCs in high doses, while in low doses, it influences cellular physiology, by affecting the gene expression with a slowing down of the endothelial lineage.

Recently, the F 1 F O -ATP synthase, due to its dual role of life enzyme as main adenosine triphosphate (ATP) maker and of death enzyme, as ATP dissipator and putative structural component of the mitochondrial permeability transition pore (mPTP), which triggers cell death, has been increasingly considered as a drug target. Accordingly, the enzyme offers new strategies to counteract the increased antibiotic resistance. The challenge is to find or synthesize compounds able to discriminate between prokaryotic and mitochondrial F 1 F O -ATP synthase, exploiting subtle structural differences to kill pathogens without affecting the host. From this perspective, the eukaryotic enzyme could also be made refractory to macrolide antibiotics by chemically produced posttranslational modifications. Moreover, because the mitochondrial F 1 F O -ATPase activity stimulated by Ca 2+ instead of by the natural modulator Mg 2+ is most likely involved in mPTP formation, effectors preferentially targeting the Ca 2+ -activated enzyme may modulate the mPTP. If the enzyme involvement in the mPTP is confirmed, Ca 2+ -ATPase inhibitors may counteract conditions featured by an increased mPTP activity, such as neurodegenerative and cardiovascular diseases and physiological aging. Conversely, mPTP opening could be pharmacologically stimulated to selectively kill unwanted cells. On the basis of recent literature and promising lab findings, the action mechanism of F 1 and F O inhibitors is considered. These molecules may act as enzyme modifiers and constitute new drugs to kill pathogens, improve compromised enzyme functions, and limit the deathly enzyme role in pathologies. The enzyme offers a wide spectrum of therapeutic strategies to fight at the molecular level diseases whose treatment is still insufficient or merely symptomatic.

An important challenge for scientific research is the production of artificial systems able to mimic the recognition mechanisms occurring at the molecular level in living systems. A valid contribution in this direction resulted from the development of molecular imprinting. By means of this technology, selective molecular recognition sites are introduced in a polymer, thus conferring it bio-mimetic properties. The potential applications of these systems include affinity separations, medical diagnostics, drug delivery, catalysis, etc. Recently, bio-sensing systems using molecularly imprinted membranes, a special form of imprinted polymers, have received the attention of scientists in various fields. In these systems imprinted membranes are used as bio-mimetic recognition elements which are integrated with a transducer component. The direct and rapid determination of an interaction between the recognition element and the target analyte (template) was an encouraging factor for the development of such systems as alternatives to traditional bio-assay methods. Due to their high stability, sensitivity and specificity, bio-mimetic sensors-based membranes are used for environmental, food, and clinical uses. This review deals with the development of molecularly imprinted polymers and their different preparation methods. Referring to the last decades, the application of these membranes as bio-mimetic sensor devices will be also reported.