Requirement for Neo1p in Retrograde Transport from the Golgi Complex to the Endoplasmic Reticulum

Neo1p from Saccharomyces cerevisiae is an essential P-type ATPase and potential aminophospholipid translocase (flippase) in the Drs2p family. We have previously implicated Drs2p in protein transport steps in the late secretory pathway requiring ADP-ribosylation factor (ARF) and clathrin. Here, we present evidence that epitope-tagged Neo1p localizes to the endoplasmic reticulum (ER) and Golgi complex and is required for a retrograde transport pathway between these organelles. Using conditional alleles of NEO1, we find that loss of Neo1p function causes cargo-specific defects in anterograde protein transport early in the secretory pathway and perturbs glycosylation in the Golgi complex. Rer1-GFP, a protein that cycles between the ER and Golgi complex in COPI and COPII vesicles, is mislocalized to the vacuole in neo1-ts at the nonpermissive temperature. These phenotypes suggest that the anterograde protein transport defect is a secondary consequence of a defect in a COPI-dependent retrograde pathway. We propose that loss of lipid asymmetry in the cis Golgi perturbs retrograde protein transport to the ER

Study on characteristics of co-firing ammonia/methane fuels under oxygen enriched combustion conditions

Having a background of utilising ammonia as an alternative fuel for power generation, exploring the feasibility of co-firing ammonia with methane is proposed to use ammonia to substitute conventional natural gas. However, improvement of the combustion of such fuels can be achieved using conditions that enable an increase of oxygenation, thus fomenting the combustion process of a slower reactive molecule as ammonia. Therefore, the present study looks at oxygen enriched combustion technologies, a proposed concept to improve the performance of ammonia/methane combustion. To investigate the characteristics of ammonia/methane combustion under oxygen enriched conditions, adiabatic burning velocity and burner stabilized laminar flame emissions were studied. Simulation results show that the oxygen enriched method can help to significantly enhance the propagation of ammonia/methane combustion without changing the emission level, which would be quite promising for the design of systems using this fuel for practical applications. Furthermore, to produce low computational-cost flame chemistry for detailed numerical analyses for future combustion studies, three reduced combustion mechanisms of the well-known Konnov’s mechanism were compared in ammonia/methane flame simulations under practical gas turbine combustor conditions. Results show that the reduced reaction mechanisms can provide good results for further analyses of oxygen enriched combustion of ammonia/methane. The results obtained in this study also allow gas turbine designers and modellers to choose the most suitable mechanism for further combustion studies and development

Distinct Endocytic Pathways Control the Rate and Extent of Synaptic Vesicle Protein Recycling

SummarySynaptic vesicles have been proposed to form through two mechanisms: one directly from the plasma membrane involving clathrin-dependent endocytosis and the adaptor protein AP2, and the other from an endosomal intermediate mediated by the adaptor AP3. However, the relative role of these two mechanisms in synaptic vesicle recycling has remained unclear. We now find that vesicular glutamate transporter VGLUT1 interacts directly with endophilin, a component of the clathrin-dependent endocytic machinery. In the absence of its interaction with endophilin, VGLUT1 recycles more slowly during prolonged, high-frequency stimulation. Inhibition of the AP3 pathway with brefeldin A rescues the rate of recycling, suggesting a competition between AP2 and -3 pathways, with endophilin recruiting VGLUT1 toward the faster AP2 pathway. After stimulation, however, inhibition of the AP3 pathway prevents the full recovery of VGLUT1 by endocytosis, implicating the AP3 pathway specifically in compensatory endocytosis

Electrochemical energy storage devices for wearable technology : a rationale for materials selection and cell design

Compatible energy storage devices that are able to withstand various mechanical deformations, while delivering their intended functions, are required in wearable technologies. This imposes constraints on the structural designs, materials selection, and miniaturization of the cells. To date, extensive efforts have been dedicated towards developing electrochemical energy storage devices for wearables, with a focus on incorporation of shape-conformable materials into mechanically robust designs that can be worn on the human body. In this review, we highlight the quantified performances of reported wearable electrochemical energy storage devices, as well as their micro-sized counterparts under specific mechanical deformations, which can be used as the benchmark for future studies in this field. A general introduction to the wearable technology, the development of the selection and synthesis of active materials, cell design approaches and device fabrications are discussed. It is followed by challenges and outlook toward the practical use of electrochemical energy storage devices for wearable applications.ASTAR (Agency for Sci., Tech. and Research, S’pore

Chem. Mat.

Nitrogen-doped porous carbon nanospheres (PCNs) with a high surface area were prepared by chemical activation of nonporous carbon nanospheres (CNs). CNs were obtained via carbonization of polypyrrole nanospheres (PNs) that were synthesized by ultrasonic polymerization of pyrrole. The catalysts Pt/PCN, Pt/CN, and Pt/PN were prepared by depositing Pt nanoparticles on supports PCNs, CNs, and PNs, respectively, using ethylene glycol chemical reduction. Nitrogen adsorption, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to characterize samples. It was found that after chemical activation using KOH, PCNs containing N functional groups (mainly N-6 and N-Q) possessed a microporous structure with a high surface area of 10 10 m(2)/g and a particle size of less than 100 nm. The electrochemical properties of samples Pt/PCN, Pt/CN, and Pt/PN, together with commercial catalysts E-TEK (40 wt % Pt loading), were comparatively investigated in methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) for fuel cells. The results showed that the catalytic activity of Pt/PN toward both reactions at room temperature is almost negligible possibly due to the poor conductivity of support PNs proven by impedance spectroscopy, in contrast with some literature reports. Compared to Pt/CN and E-TEK catalyst, Pt/PCN revealed an enhanced mass activity in ORR and MOR because of the high dispersion of small Pt nanoparticles, the presence of nitrogen species, and developed microporous structure of support PCNs.Nitrogen-doped porous carbon nanospheres (PCNs) with a high surface area were prepared by chemical activation of nonporous carbon nanospheres (CNs). CNs were obtained via carbonization of polypyrrole nanospheres (PNs) that were synthesized by ultrasonic polymerization of pyrrole. The catalysts Pt/PCN, Pt/CN, and Pt/PN were prepared by depositing Pt nanoparticles on supports PCNs, CNs, and PNs, respectively, using ethylene glycol chemical reduction. Nitrogen adsorption, X-ray diffraction, thermogravimetric analysis, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to characterize samples. It was found that after chemical activation using KOH, PCNs containing N functional groups (mainly N-6 and N-Q) possessed a microporous structure with a high surface area of 10 10 m(2)/g and a particle size of less than 100 nm. The electrochemical properties of samples Pt/PCN, Pt/CN, and Pt/PN, together with commercial catalysts E-TEK (40 wt % Pt loading), were comparatively investigated in methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR) for fuel cells. The results showed that the catalytic activity of Pt/PN toward both reactions at room temperature is almost negligible possibly due to the poor conductivity of support PNs proven by impedance spectroscopy, in contrast with some literature reports. Compared to Pt/CN and E-TEK catalyst, Pt/PCN revealed an enhanced mass activity in ORR and MOR because of the high dispersion of small Pt nanoparticles, the presence of nitrogen species, and developed microporous structure of support PCNs

AMP-Activated Kinase Links Serotonergic Signaling to Glutamate Release for Regulation of Feeding Behavior in C. elegans

Serotonergic regulation of feeding behavior has been studied intensively, both for an understanding of the basic neurocircuitry of energy balance in various organisms and as a therapeutic target for human obesity. However, its underlying molecular mechanisms remain poorly understood. Here, we show that neural serotonin signaling in C. elegans modulates feeding behavior through inhibition of AMP-activated kinase (AMPK) in interneurons expressing the C. elegans counterpart of human SIM1, a transcription factor associated with obesity. In turn, glutamatergic signaling links these interneurons to pharyngeal neurons implicated in feeding behavior. We show that AMPK-mediated regulation of glutamatergic release is conserved in rat hippocampal neurons. These findings reveal cellular and molecular mediators of serotonergic signaling

Intrinsically Conductive Perovskite Oxides with Enhanced Stability and Electrocatalytic Activity for Oxygen Reduction Reactions

© 2016 American Chemical Society.The oxygen reduction reaction (ORR) is traditionally catalyzed by carbon-supported precious metals, heteroatom-doped carbons, and transition-metal-carbon hybrids. Despite their good electric conductivity and high catalytic activities, these carbon-containing catalysts suffer from electrochemical carbon corrosion which limits their utility in metal-air batteries and fuel cells. Here, we report a class of perovskite La0.5Sr0.5Mn1-xNixO3-δ nanocrystals that are intrinsically conductive with good electrocatalytic activity for the ORR. Among these perovskites, La0.5Sr0.5Mn0.9Ni0.1O3-δ (δ = 0.06, LSMN) exhibited the highest electrocatalytic activity for ORR with an onset potential of 1.02 V, a half-wave potential of 0.80 V, and a Tafel slope of -68 mV decade-1 in 0.1 M potassium hydroxide aqueous solution. Negligible degradation of oxygen reduction currents was observed after 300 cyclic voltammetry scans from 1.08 to 0.15 V. We demonstrated that the electrically conductive perovskites with transition-metal redox couples and oxygen vacancies are essential. Our work demonstrates the possibility of carbon-free oxygen electrocatalysis with widely promising applications. (Chemical Equation Presented).Link_to_subscribed_fulltex