PRRSV GP5 inhibits the antivirus effects of chaperone-mediated autophagy by targeting LAMP2A.

Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral system. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus with a large economic impact on the swine industry. At present, studies on the escape mechanism of PRRSV in the autophagy process, especially through chaperone-mediated autophagy (CMA), are limited. This study confirmed that PRRSV glycoprotein 5 (GP5) could disrupt the formation of the GFAP-LAMP2A complex by inhibiting the MTORC2/PHLPP1/GFAP pathway, promoting the dissociation of the pGFAP-EF1α complex, and blocking the K63-linked polyubiquitination of LAMP2A to inhibit the activity of CMA. Further research demonstrated that CMA plays an anti-PRRSV role by antagonizing nonstructural protein 11 (NSP11)-mediated inhibition of type I interferon (IFN-I) signaling. Taken together, these results indicate that PRRSV GP5 inhibits the antiviral effect of CMA by targeting LAMP2A. This research provides new insight into the escape mechanism of immunosuppressive viruses in CMA. IMPORTANCE: Viruses have evolved sophisticated mechanisms to manipulate autophagy to evade degradation and immune responses. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus that causes enormous economic losses in the swine industry. However, the mechanism by which PRRSV manipulates autophagy to defend against host antiviral effects remains unclear. In this study, we found that PRRSV GP5 interacts with LAMP2A and disrupts the formation of the GFAP-LAMP2A complex, thus inhibiting the activity of CMA and subsequently enhancing the inhibitory effect of the NSP11-mediated IFN-I signaling pathway, ultimately facilitating PRRSV replication. Our study revealed a novel mechanism by which PRRSV escapes host antiviral effects through CMA, providing a potential host target, LAMP2A, for developing antiviral drugs and contributing to understanding the escape mechanism of immunosuppressive viruses.

Selective Activation of Lattice Oxygen Site Through Coordination Engineering to Boost the Activity and Stability of Oxygen Evolution Reaction.

Although Ru-based materials are among the outstanding catalysts for the oxygen evolution reaction (OER), the instability issue still haunts them and impedes the widespread application. The instability of Ru-based OER catalysts is generally ascribed to the formation of soluble species through the over-oxidation of Ru and structural decomposition caused by involvement of lattice oxygen. Herein, an effective strategy of selectively activating the lattice oxygen around Ru site is proposed to improve the OER activity and stability. Our synthesized spinel-type electrocatalyst of Ru and Zn co-doped Co3O4 showed an ultralow overpotential of 172 mV at 10 mA cm-2 and a long-term stability reaching to 100 hours at 10 mA cm-2 for alkaline OER. The experimental results and theoretical simulations demonstrated that the lattice oxygen site jointly connected with the octahedral Ru and tetrahedral Zn atoms became more active than other oxygen sites near Ru atom, which further lowered the reaction energy barriers and avoided generating excessive oxygen vacancies to enhance the structural stability of Ru sites. The findings hope to provide a new perspective to improve the catalytic activity of Ru-incorporated OER catalysts and the stability of lattice-oxygen-mediated mechanism.

Mass Spectrometry-Based Proteomic Analysis of Potential Host Proteins Interacting with GP5 in PRRSV-Infected PAMs.

Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus causing a large economic impact on the swine industry. The structural protein GP5 of PRRSV plays a pivotal role in its pathogenicity and immune evasion. Virus-host interactions play a crucial part in viral replication and immune escape. Therefore, understanding the interactions between GP5 and host proteins are significant for porcine reproductive and respiratory syndrome (PRRS) control. However, the interaction network between GP5 and host proteins in primary porcine alveolar macrophages (PAMs) has not been reported. In this study, 709 GP5-interacting host proteins were identified in primary PAMs by immunoprecipitation coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Bioinformatics analysis revealed that these proteins were involved in multiple cellular processes, such as translation, protein transport, and protein stabilization. Subsequently, immunoprecipitation and immunofluorescence assay confirmed that GP5 could interact with antigen processing and presentation pathways related proteins. Finally, we found that GP5 may be a key protein that inhibits the antigen processing and presentation pathway during PRRSV infection. The novel host proteins identified in this study will be the candidates for studying the biological functions of GP5, which will provide new insights into PRRS prevention and vaccine development.

Sonication strategy for anchoring single metal atom oxides (W, Cu, Co) on CeO2-rGO for boosting electrocatalytic oxygen evolution reaction.

In the field of electrocatalysis, single-atomic-layer tungsten, copper, and cobalt oxide on CeO2, ethylene diamine (ED) and reduced graphene oxide (rGO) supported materials shows tremendous potential. Despite the enormous interest in single metal atom oxide (SMAO) catalysts, it is still very difficult to directly convert readily available bulk metal oxide into single atom oxide. It is crucial and tough to create high performance materials for the oxygen evolution reaction (OER) in an alkaline environment. Herein, a single tungsten, copper and cobalt atom oxide (SMAO) anchored on the CeO2 atomic layer and overall components deposited on the rGO (rGO-ED-CeO2-WCuCo) is prepared through a one-pot sonication technique. The presence of SMAO is identified by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging. The electrocatalytic performance of final rGO-ED-CeO2-WCuCo-30 nanocomposite for the OER in 1 M KOH electrolyte is evidenced by providing low overpotential of 283 mV at 10 mA cm-2. The Tafel slope for OER using rGO-ED-CeO2-WCuCo-30 electrocatalysts is 57.03 mV dec-1. The electrocatalytic activity of rGO-ED-CeO2-WCuCo-30 nanocomposites for OER was noticeably increased when compared to bare CeO2 nanorods (401 mV), rGO-ED-CeO2-WCo-30 (345 mV), rGO-ED-CeO2-WCu-30 (340 mV) and rGO-ED-CeO2-WCuCo-20 (321 mV) samples.

Adsorption-enhanced catalytic oxidation for long-lasting dynamic degradation of organic dyes by porous manganese-based biopolymeric catalyst.

Improving the adsorption kinetics of metal-oxide catalysts is critical for the enhancement of catalytic performance in heterogeneous catalytic oxidation reactions. Herein, based on the biopolymer pomelo peels (PP) and metal-oxide catalyst manganese oxide (MnOx), an adsorption-enhanced catalyst (MnOx-PP) was constructed for catalytic organic dyes oxidative-degradation. MnOx-PP shows excellent methylene blue (MB) and total carbon content (TOC) removal efficiency of 99.5 % and 66.31 % respectively, and keeps the long-lasting stable dynamic degradation efficiency during 72 h based on the self-built continuous single-pass MB purification device. The chemical structure similarity and negative-charge polarity sites of the biopolymer PP improve the adsorption kinetics of organic macromolecule MB, and construct the adsorption-enhanced catalytic oxidation microenvironment. Meanwhile, the adsorption-enhanced catalyst MnOx-PP obtains lower ionization potential and O2 adsorption energy to promote the continuous generation of active substance (O2*, OH*) for the further catalytic oxidation of adsorbed MB molecules. This work explored the adsorption-enhanced catalytic oxidation mechanism for the degradation of organic pollutants, and provided a feasible technical idea for designing adsorption-enhanced catalysts for the long-lasting efficient removal of organic dyes.

Construction of single tungsten/copper atom oxide supported on the surface of TiO2 for the higher activity of electrocatalytic water splitting and photodegradation of organic pollutant.

Intense studies are being carried out on single atom catalysts that exhibit remarkable activity and selectivity. To enhance their catalytic abilities, one must have a thorough understanding of the properties of the single metal atom active site and its dynamics in the working state. Herein, we report single metal atom oxide (SMAO) (metal: W/Cu) anchored on TiO2-rGO nanomaterials (SMAO-ED-TiO2-rGO) by simple sonication process. It is efficient for the electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and photocatalytic degradation of pharmaceutical pollutant. The uniform dispersion of the tungsten/copper metal atom oxide over a TiO2-rGO materials is detected by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The SMAO-ED-TiO2-rGO nanocatalyst has shown impressive HER/OER activity with an overpotential of 121/295 mV at (-)10 mA cm-2 current density and the low Tafel slope of 96/60.3 mV dec-1 in 1 M KOH solution. Further, SMAO-ED-TiO2-rGO nanocatalyst was used for the photocatalytic degradation of ciprofloxacin (CF). After 60 min of UV light irradiation, the SMAO-ED-TiO2-rGO nanocatalyst efficiently photodegraded 98.5% of CF while retaining its activity for five cycles. Superoxide radicals (O2•-) are found to be the main reactive species required in the photodegradation of CF, according to scavenger study of the SMAO-ED-TiO2-rGO nanocatalyst for CF degradation.

Determination of Crystallographic Orientation and Exposed Facets of Titanium Oxide Nanocrystals.

Titanium dioxide (TiO2 ) nanocrystals have attracted great attention in heterogeneous photocatalysis and photoelectricity fields for decades. However, contradicting conclusions on the crystallographic orientation and exposed facets of TiO2 nanocrystals frequently appear in the literature. Herein, using anatase TiO2 nanocrystals with highly exposed {001} facets as a model, the misleading conclusions that exist on anatase nanocrystals are clarified. Although TiO2 -001 nanocrystals are recognized to be dominated by {001} facets, in fact, anatase nanocrystals with both dominant {001} and {111} facets always co-exist due to the similarities in the lattice fringes and intersection angles between the two types of facets (0.38 nm and 90° in the [001] direction, 0.35 nm and 82° in the [111] direction). A paradigm for determining the crystallographic orientation and exposed facets based on transmission electron microscopy (TEM) analysis, which provides a universal methodology to nanomaterials for determining the orientation and exposed facets, is also given.

High activity and selectivity of single palladium atom for oxygen hydrogenation to H2O2.

Nanosized palladium (Pd)-based catalysts are widely used in the direct hydrogen peroxide (H2O2) synthesis from H2 and O2, while its selectivity and yield remain inferior because of the O-O bond cleavage from both the reactant O2 and the produced H2O2, which is assumed to have originated from various O2 adsorption configurations on the Pd nanoparticles. Herein, single Pd atom catalyst with high activity and selectivity is reported. Density functional theory calculations certify that the O-O bond breaking is significantly inhibited on the single Pd atom and the O2 is easier to be activated to form *OOH, which is a key intermediate for H2O2 synthesis; in addition, H2O2 degradation is shut down. Here, we show single Pd atom catalyst displays a remarkable H2O2 yield of 115 mol/gPd/h and H2O2 selectivity higher than 99%; while the concentration of H2O2 reaches 1.07 wt.% in a batch.

Enhanced the synergistic degradation effect between active hydroxyl and reactive oxygen species for indoor formaldehyde based on platinum atoms modified MnOOH/MnO2 catalyst.

Maintaining high activity during prolonged catalysis is always the pursuit in catalytic degradation of organic pollutants. For indoor formaldehyde (HCHO) degradation, the accumulation of intermediates is the major factor limiting the conversion of HCHO to final product CO2 (HCHO-to-CO2 conversion) and long-lasting catalysis. Herein, a three-dimensional radialized nanostructure catalyst self-assembled by MnOOH/MnO2 nanosheets anchored with Pt single atoms (PtSA-MnOOH/MnO2 with a trace platinum loading amount of 0.09%) is developed by thermally assisted two-step electrochemical method, which achieves enhanced CO2 production in catalytic HCHO degradation at the room temperature by the collaborative action of active hydroxyl (OH*) and active oxygen species (O2*). By boosting intermediates' decomposing, the catalyst implements real-time HCHO-to-CO2 conversion (∼85.7%) and long-term continuous HCHO removal (∼98%) during 100 h in a 15 ppm HCHO atmosphere at 25 °C under a weight hourly space velocity of 30000 mL/gcat∙h. Density functional theory calculation shows that the formation energy of O2* from O2 over PtSA-MnOOH/MnO2 is nearly half lower than that over Pt-MnO2 catalyst. And decomposing accumulated intermediates gives the credit to OH* species sustainably generated by the combined action of MnOOH and O2*. The synergistic action between PtSA and MnOOH contributes to the continuous production of O2* and OH* for enhancing CO2 production in indoor catalytic formaldehyde degradation.

Electronically Engineering Water Resistance in Methane Combustion with an Atomically Dispersed Tungsten on PdO Catalyst.

Improving the low-temperature water-resistance of methane combustion catalysts is of importance for industrial applications and it is challenging. A stepwise strategy is presented for the preparation of atomically dispersed tungsten species at the catalytically active site (Pd nanoparticles). After an activation process, a Pd-O-W1 -like nanocompound is formed on the PdO surface with an atomic scale interface. The resulting supported catalyst has much better water resistance than the conventional catalysts for methane combustion. The integrated characterization results confirm that catalytic combustion of methane involves water, proceeding via a hydroperoxyl-promoted reaction mechanism on the catalyst surface. The results of density functional theory calculations indicate an upshift of the d-band center of palladium caused by electron transfer from atomically dispersed tungsten, which greatly facilitates the adsorption and activation of oxygen on the catalyst.

Direct Synthesis of Stable 1T-MoS2 Doped with Ni Single Atoms for Water Splitting in Alkaline Media.

Metallic MoS2 (i.e., 1T-MoS2 ) is considered as the most promising precious-metal-free electrocatalyst with outstanding hydrogen evolution reaction (HER) performance in acidic media comparable to Pt. However, sluggish kinematics of HER in alkaline media and its inability for the oxygen evolution reaction (OER), hamper its development as bifunctional catalysts. The instability of 1T-MoS2 further impedes its applications for scaling up, calling an urgent need for simple synthesis to produce stable 1T-MoS2 . In this work, the challenge of 1T-MoS2 synthesis is first addressed using a direct one-step hydrothermal method by adopting ascorbic acid. 1T-MoS2 with flower-like morphology is obtained, and transition metals (Ni, Co, Fe) are simultaneously doped into 1T-MoS2 . Ni-1T-MoS2 achieves an enhanced bifunctional catalytic activity for both HER and OER in alkaline media, where the key role of Ni doping as single atom is proved to be essential for boosting HER/OER activity. Finally, a Ni-1T-MoS2 ||Ni-1T-MoS2 electrolyzer is fabricated, reaching a current density of 10 mA cm-2 at an applied cell voltage of only 1.54 V for overall water splitting.

Genuine Active Species Generated from Fe3 N Nanotube by Synergistic CoNi Doping for Boosted Oxygen Evolution Catalysis.

The surface reconstruction of oxygen evolution reaction (OER) catalysts has been proven favorable for enhancing its catalytic activity. However, what is the active site and how to promote the active species generation remain unclear and are still under debate. Here, the in situ synthesis of CoNi incorporated Fe3 N nanotubes (CoNi-Fe3 N) on the iron foil through the anodization/electrodeposition/nitridation process for use of boosted OER catalysis is reported. The synergistic CoNi doping induces the lattice expansion and up shifts the d-band center of Fe3 N, which enhances the adsorption of hydroxyl groups from electrolyte during the OER catalysis, facilitating the generation of active CoNi-FeOOH on the Fe3 N nanotube surface. As a result of this OER-conditioned surface reconstruction, the optimized catalyst requires an overpotential of only 285 mV at a current density of 10 mA cm-2 with a Tafel slope of 34 mV dec-1 , outperforming commercial RuO2 catalysts. Density functional theory (DFT) calculations further reveal that the Ni site in CoNi-FeOOH modulates the adsorption of OER intermediates and delivers a lower overpotential than those from Fe and Co sites, serving as the optimal active site for excellent OER performance.