Restructuring of 4H Phase Au Nanowires and its Catalytic Behavior toward CO Electro-oxidation

Au nanowires in 4H crystalline phase(4H Au NWs)are synthesized by colloid solution methods.The crys-talline phase and surface structure as well as its performance toward electrochemical oxidation of CO be-fore and after removing adsorbed oleylamine molecules(OAs)intro-duced from its synthesis are evaluat-ed by high-resolution transmission electron microscopy(HR-TEM),X-ray diffraction(XRD),underpoten-tial deposition of Pb(Pb-upd)and cyclic voltammetry.Different methods,i.e.acetic acid cleaning,electrochemical oxidation cleaning,and diethylamine replacement,have been tried to remove the adsorbed OAs.For all methods,upon the removal of the adsorbed OAs,the morphology of 4H gold nanoparticles is found to gradually change from nanowires to large dumbbell-shaped nanoparticles,accompanying with a transition from the 4H phase to the face-centered cubic phase.On the other hand,the Pb-upd results show that the sample sur-faces have almost the same facet composition before and after removal of the adsorbed OAs.After electrochemical cleaning with continuous potential scans up to 1.3 V,CO electro-oxida-tion activity of the 4H Au sample is significantly improved.The CO electro-oxidation activi-ty is compared with results on the three basel Au single crystalline surfaces reported in the lit-erature,possible origins for its enhancement are discussed.

Contact Electrification Spectrum for Performance Enhancement Mechanism Investigation of Triboelectric Nanogenerators based on Silicone Elastomers with Different Surface Microstructures

Triboelectric nanogenerators(TENGs)based on conjunctive effects of contact electrification(CE)and electrostatic induction are emerging as a new mechanical energy harvesting and sensing technique for promising applications in smart wearables,Internet of Things(IoTs),etc.The surface microstructure of a flexible triboelectric material for the increase of surface area is a common strategy for performance enhancement of TENGs,but the real roles of surface microstructures on their output performance are still not explicit due to the lack of suitable analysis tool and rational experimental design.Taking advantages of the surface-sensitive characteristic of CE effect,this work exploited and developed the electric signal patterns generated by single impact of TENGs as a kind of CE spectrum to analyze and speculate the real roles of surface microstructures of flexible triboelectric materials on the output performance of TENGs.Firstly,four different kinds of surface microstructures,namely planar surface(PS)and three combinations of two basic surface microstructures,i.e.,micro lens arrays(MLAs),fabric textures(FTs),and hierarchical structures of MLAs on FTs(MLA/FTs),were elaborately designed and introduced for an identical triboelectric material(i.e.,silicone elastomer)by a(micro)molding synthesis route.Then they were used for assembly of TENGs based on vertical contact mode to conduct performance evaluation under the same triggering conditions.Through systematic analysis and comparison of their highly repeatable CE spectra by programmed machine,it was found that the surface microstructure for a flexible triboelectric material to maximally enhance the output performance of a TENG shall achieve a positive synergistic effect of increasing triboelectric charge density,effective contact area and contacting/separating velocity,rather than simple increase of its surface area.

MAVS-loaded unanchored Lys63-linked polyubiquitin chains activate the RIG-I-MAVS signaling cascade

The adaptor molecule MAVS forms prion-like aggregates to govern the RIG-I-like receptor(RLR)signaling cascade.Lys63(K63)-linked polyubiquitination is critical for MAVS aggregation,yet the underlying mechanism and the corresponding E3 ligases and deubiquitinating enzymes(DUBs)remain elusive.Here,we found that the K63-linked polyubiquitin chains loaded on MAVS can be directly recognized by RIG-I to initiate RIG-I-mediated MAVS aggregation with the prerequisite of the CARDRIG-I-CARDMAVS interaction.Interestingly,many K63-linked polyubiquitin chains attach to MAVS via an unanchored linkage.We identified Ube2N as a major ubiquitin-conjugating enzyme for MAVS and revealed that Ube2N cooperates with the E3 ligase Riplet and TRIM31 to promote the unanchored K63-linked polyubiquitination of MAVS.In addition,we identified USP10 as a direct DUB that removes unanchored K63-linked polyubiquitin chains from MAVS.Consistently,USP10 attenuates RIG-I-mediated MAVS aggregation and the production of type I interferon.Mice with a deficiency in USP10 show more potent resistance to RNA virus infection.Our work proposes a previously unknown mechanism for the activation of the RLR signaling cascade triggered by MAVS-attached unanchored K63-linked polyubiquitin chains and establishes the DUB USP10 and the E2:E3 pair Ube2N-Riplet/TRIM31 as a specific regulatory system for the unanchored K63-linked ubiquitination and aggregation of MAVS upon viral infection.

Genome mining combined metabolic shunting and OSMAC strategy of an endophytic fungus leads to the production of diverse natural products

Endophytic fungi are promising producers of bioactive small molecules.Bioinformatic analysis of the genome of an endophytic fungus Penicillium dangeardii revealed 43 biosynthetic gene clusters,exhibited its strong ability to produce numbers of secondary metabolites.However,this strain mainly produce rubratoxins alone with high yield in varied culture conditions,suggested most gene clusters are silent.Efforts for mining the cryptic gene clusters in P.dangeardii,including epigenetic regulation and one-strain-many-compounds(OSMAC)approach were failed probably due to the high yield of rubratoxins.A metabolic shunting strategy by deleting the key gene for rubratoxins biosynthesis combining with optimization of culture condition successfully activated multiple silent genes encoding for other polyketide synthases(PKSs),and led to the trace compounds detectable.As a result,a total of 23 new compounds including azaphilone monomers,dimers,turimers with unprecedented polycyclic bridged heterocycle and spiral structures,as well as siderophores were identified.Some compounds showed significant cytotoxicities,anti-inflammatory or antioxidant activities.The attractive dual PKS s gene clusters for azaphilones biosynthesis were mined by bioinformatic analysis and overexpression of a pathway specific transcription factor.Our work therefor provides an efficient approach to mine the chemical diversity of endophytic fungi.

Epigenetic modification in histone deacetylase deletion strain of Calcarisporium arbuscula leads to diverse diterpenoids

Epigenetic modifications have been proved to be a powerful way to activate silent gene clusters and lead to diverse secondary metabolites in fungi. Previously, inactivation of a histone H3 deacetylase in Calcarisporium arbuscula had led to pleiotropic activation and overexpression of more than 75% of the biosynthetic genes and isolation of ten compounds. Further investigation of the crude extract of C. arbuscula Δhda A strain resulted in the isolation of twelve new diterpenoids including three cassanes(1-3), one cleistanthane(4), six pimaranes(5-10), and two isopimaranes(11 and 12) along with two know cleistanthane analogues. Their structures were elucidated by extensive NMR spectroscopic data analysis. Compounds 2 and 4 showed potent inhibitory effects on the expression of MMP1 and MMP2(matrix metalloproteinases family) in human breast cancer(MCF-7) cells.

OTUD5 promotes innate antiviral and antitumor immunity through deubiquitinating and stabilizing STING

Stimulator of interferon genes(STING)is an adaptor protein that is critical for effective innate antiviral and antitumor immunity.The activity of STING is heavily regulated by protein ubiquitination,which is fine-tuned by both E3 ubiquitin ligases and deubiquitinases.Here,we report that the deubiquitinase OTUD5 interacts with STING,cleaves its K48-linked polyubiquitin chains,and promotes its stability.Consistently,knockout of OTUD5 resulted in faster turnover of STING and subsequently impaired type I IFN signaling following cytosolic DNA stimulation.More importantly,Lyz2-Cre Otud5^(fl/Y) mice and CD11-Cre Otud5^(fl/Y) mice showed more susceptibility to herpes simplex virus type 1(HSV-1)infection and faster development of melanomas than their corresponding control littermates,indicating that OTUD5 is indispensable for STING-mediated antiviral and antitumor immunity.Our data suggest that OTUD5 is a novel checkpoint in the cGAS-STING cytosolic DNA sensing pathway.

Activation of an unconventional meroterpenoid gene cluster in Neosartorya glabra leads to the production of new berkeleyacetals

Fungal genomes carry many gene clusters seemingly capable of natural products biosynthesis,yet most clusters remain cryptic or down-regulated. Genome mining revealed an unconventional paraherquonin-like meroterpenoid biosynthetic gene cluster in the chromosome of Neosartorya glabra.The cryptic or down-regulated pathway was activated by constitutive expression of pathway-specific regulator gene ber A encoded within ber biosynthetic gene cluster. Chemical analysis of mutant Ng-OE:ber A extracts enabled the isolation of four berkeleyacetal congeners, in which two of them are new. On the basis of careful bioinformatic analysis of the coding enzymes in the ber gene cluster, the biosynthetic pathway of berkeleyacetals was proposed. These results indicate that this approach would be valuable for discovery of novel natural products and will accelerate the exploitation of prodigious natural products in filamentous fungi.

USP3 deubiquitinates and stabilizes the adapter protein ASC to regulate inflammasome activation

Inflammasomes are essential components of the innate immune system and its defense against infections,whereas the dysregulation of inflammasome activation has a detrimental effect on human health.The activation of inflammasomes is subjected to tight regulation to maintain immune homeostasis,yet the underlying mechanism remains elusive.Here,we identify USP3 as a direct deubiquitinating enzyme(DUB)for ASC,the central adapter mediating the assembly and activation of most inflammasomes.USP3 removes the K48-linked ubiquitination on ASC and strengthens its stability by blocking proteasomal degradation.Additionally,USP3 promotes inflammasome activation,and this function was confirmed in mouse models of aluminum(Alum)-induced peritonitis,F.novicida infection and flagellin-induced pneumonia in vivo.Our work unveils that USP3 functions as a key regulator of ASC ubiquitination and maintains the physiological role of ASC in mediating inflammasome activation,and we propose a new mechanism by which the ubiquitination of ASC regulates inflammasome activation.

Privacy preserving divisible double auction with a hybridized TEE-blockchain system

Double auction mechanisms have been designed to trade a variety of divisible resources(e.g.;electricity,mobile data,and cloud resources)among distributed agents.In such divisible double auction,all the agents(both buyers and sellers)are expected to submit their bid profiles,and dynamically achieve the best responses.In practice,these agents may not trust each other without a market mediator.Fortunately,smart contract is extensively used to ensure digital agreement among mutually distrustful agents.The consensus protocol helps the smart contract execution on the blockchain to ensure strong integrity and availability.However,severe privacy risks would emerge in the divisible double auction since all the agents should disclose their sensitive data such as the bid profiles(i.e.,bid amount and prices in different iterations)to other agents for resource allocation and such data are replicated on all the nodes in the network.Furthermore,the consensus requirements will bring a huge burden for the blockchain,which impacts the overall performance.To address these concerns,we propose a hybridized TEE-Blockchain system(system and auction mechanism co-design)to privately execute the divisible double auction.The designed hybridized system ensures privacy,honesty and high efficiency among distributed agents.The bid profiles are sealed for optimally allocating divisible resources while ensuring truthfulness with a Nash Equilibrium.Finally,we conduct experiments and empirical studies to validate the system and auction performance using two real-world applications.

Privacy preserving divisible double auction with a hybridized TEE‑blockchain system

Double auction mechanisms have been designed to trade a variety of divisible resources(e.g.,electricity,mobile data,and cloud resources)among distributed agents.In such divisible double auction,all the agents(both buyers and sellers)are expected to submit their bid profiles,and dynamically achieve the best responses.In practice,these agents may not trust each other without a market mediator.Fortunately,smart contract is extensively used to ensure digital agreement among mutually distrustful agents.The consensus protocol helps the smart contract execution on the blockchain to ensure strong integrity and availability.However,severe privacy risks would emerge in the divisible double auction since all the agents should disclose their sensitive data such as the bid profiles(i.e.,bid amount and prices in different iterations)to other agents for resource allocation and such data are replicated on all the nodes in the network.Furthermore,the consensus requirements will bring a huge burden for the blockchain,which impacts the overall performance.To address these concerns,we propose a hybridized TEE-Blockchain system(system and auction mechanism co-design)to privately execute the divisible double auction.The designed hybridized system ensures privacy,honesty and high efficiency among distributed agents.The bid profiles are sealed for optimally allocating divisible resources while ensuring truthfulness with a Nash Equilibrium.Finally,we conduct experiments and empirical studies to validate the system and auction performance using two real-world applications.

TRIM31 facilitates K27-linked polyubiquitination of SYK to regulate antifungal immunity

Spleen tyrosine kinase(SYK)is a non-receptor tyrosine kinase,which plays an essential role in both innate and adaptive immunity.However,the key molecular mechanisms that regulate SYK activity are poorly understood.Here we identified the E3 ligase TRIM31 as a crucial regulator of SYK activation.We found that TRIM31 interacted with SYK and catalyzed K27-linked polyubiquitination at Lys375 and Lys517 of SYK.This K27-linked polyubiquitination of SYK promoted its plasma membrane translocation and binding with the C-type lectin receptors(CLRs).