Selective Photoelectrochemical Oxidation of Glycerol to Glyceric Acid on (002) Facets Exposed WO3 Nanosheets.

Glycerol is a byproduct of biodiesel production. Selective photoelectrochemical oxidation of glycerol to high value-added chemicals offers an economical and sustainable approach to transform renewable feedstock as well as store green energy at the same time. In this work, we synthesized monoclinic WO3 nanosheets with exposed (002) facets, which could selectively oxidize glycerol to glyceric acid (GLYA) with a photocurrent density of 1.7 mA cm-2 , a 73 % GLYA selectivity and a 39 % GLYA Faradaic efficiency at 0.9 V vs. reversible hydrogen electrode (RHE) under AM 1.5G illumination (100 mW cm-2 ). Compared to (200) facets exposed WO3 , a combination of experiments and theoretical calculations indicates that the superior performance of selective glycerol oxidation mainly originates from the better charge separation and prolonged carrier lifetime resulted from the plenty of surface trapping states, lower energy barrier of the glycerol-to-GLYA reaction pathway, more abundant active sites and stronger oxidative ability of photogenerated holes on the (002) facets exposed WO3 . Our findings show great potential to significantly contribute to the sustainable and environmentally friendly chemical processes via designing high performance photoelectrochemical cell via facet engineering for renewable feedstock transformation.

Regulation of FLC nuclear import by coordinated action of the NUP62-subcomplex and importin ß SAD2.

Flowering locus C (FLC) is a central transcriptional repressor that controls flowering time. However, how FLC is imported into the nucleus is unknown. Here, we report that Arabidopsis nucleoporins 62 (NUP62), NUP58, and NUP54 composed NUP62-subcomplex modulates FLC nuclear import during floral transition in an importin α-independent manner, via direct interaction. NUP62 recruits FLC to the cytoplasmic filaments and imports it into the nucleus through the NUP62-subcomplex composed central channel. Importin ß supersensitive to ABA and drought 2 (SAD2), a carrier protein, is critical for FLC nuclear import and flower transition, which facilitates FLC import into the nucleus mainly through the NUP62-subcomplex. Proteomics, RNA-seq, and cell biological analyses indicate that the NUP62-subcomplex mainly mediates the nuclear import of cargos with unconventional nuclear localization sequences (NLSs), such as FLC. Our findings illustrate the mechanisms of the NUP62-subcomplex and SAD2 on FLC nuclear import process and floral transition, and provide insights into the role of NUP62-subcomplex and SAD2 in protein nucleocytoplasmic transport in plants.

De novo transcriptome assembly and metabolomic analysis of three tissue types in Cinnamomum cassia.

Objective: The barks, leaves, and branches of Cinnamomum cassia have been historically used as a traditional Chinese medicine, spice, and food preservative, in which phenylpropanoids are responsible compounds. However phenylpropanoid biosynthesis pathways are not clear in C. cassia. We elucidated the pathways by descriptive analyses of differentially expressed genes related to phenylpropanoid biosynthesis as well as to identify various phenylpropanoid metabolites. Methods: Chemical analysis, metabolome sequencing, and transcriptome sequencing were performed to investigate the molecular mechanisms underlying the difference of active components content in the barks, branches and leaves of C. cassia. Results: Metabolomic analysis revealed that small amounts of flavonoids, coumarine, and cinnamaldehyde accumulated in both leaves and branches. Transcriptome analysis showed that genes associated with phenylpropanoid and flavonoid biosynthesis were downregulated in the leaves and branches relative to the barks. The observed differences in essential oil content among the three tissues may be attributable to the differential expression of genes involved in the phenylpropanoid and flavonoid metabolic pathways. Conclusion: This study identified the key genes in the phenylpropanoid pathway controling the flavonoid, coumarine, and cinnamaldehyde contents in the barks, branches and leaves by comparing the transcriptome and metabolome. These findings may be valuable in assessing phenylpropanoid and flavonoid metabolites and identifying specific candidate genes that are related to the synthesis of phenylpropanoids and flavonoids in C. cassia.

IQ67 DOMAIN protein 21 is critical for indentation formation in pavement cell morphogenesis.

In plants, cortical microtubules anchor to the plasma membrane in arrays and play important roles in cell shape. However, the molecular mechanism of microtubule binding proteins, which connect the plasma membrane and cortical microtubules in cell morphology remains largely unknown. Here, we report that a plasma membrane and microtubule dual-localized IQ67 domain protein, IQD21, is critical for cotyledon pavement cell (PC) morphogenesis in Arabidopsis. iqd21 mutation caused increased indentation width, decreased lobe length, and similar lobe number of PCs, whereas IQD21 overexpression had a different effect on cotyledon PC shape. Weak overexpression led to increased lobe number, decreased indentation width, and similar lobe length, while moderate or great overexpression resulted in decreased lobe number, indentation width, and lobe length of PCs. Live-cell observations revealed that IQD21 accumulation at indentation regions correlates with lobe initiation and outgrowth during PC development. Cell biological and genetic approaches revealed that IQD21 promotes transfacial microtubules anchoring to the plasma membrane via its polybasic sites and bundling at the indentation regions in both periclinal and anticlinal walls. IQD21 controls cortical microtubule organization mainly through promoting Katanin 1-mediated microtubule severing during PC interdigitation. These findings provide the genetic evidence that transfacial microtubule arrays play a determinant role in lobe formation, and the insight into the molecular mechanism of IQD21 in transfacial microtubule organization at indentations and puzzle-shaped PC development.

Two Arabidopsis MYB-SHAQKYF transcription repressors regulate leaf wax biosynthesis via transcriptional suppression on DEWAX.

Plant cuticular wax accumulation limits nonstomatal transpiration and is regulated by external environmental stresses. DEWAX (DECREASE WAX BIOSYNTHESIS) plays a vital role in diurnal wax biosynthesis. However, how DEWAX expression is controlled and the molecular mechanism of wax biosynthesis regulated by the diurnal cycle remains largely unknown. Here, we identified two Arabidopsis MYB-SHAQKYF transcription factors, MYS1 and MYS2, as new regulators in wax biosynthesis and drought tolerance. Mutations of both MYS1 and MYS2 caused significantly reduced leaf wax, whereas overexpression of MYS1 or MYS2 increased leaf wax biosynthesis and enhanced drought tolerance. Our results demonstrated that MYS1 and MYS2 act as transcription repressors and directly suppress DEWAX expression via ethylene response factor-associated amphiphilic repression motifs. Genetic interaction analysis with DEWAX, SPL9 (SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 9), and CER1 (ECERIFERUM 1) in wax biosynthesis and under drought stresses demonstrated that MYS1 and MYS2 act upstream of the DEWAX-SPL9 module, thus regulating CER1 expression. Expression analysis suggested that the diurnal expression pattern of DEWAX is partly regulated by MYS1 and MYS2. Our findings demonstrate the roles of two unidentified transcription repressors, MYS1 and MYS2, in wax biosynthesis and provide insights into the mechanism of diurnal cycle-regulated wax biosynthesis.

Serine Hydroxymethyltransferase 1 Is Essential for Primary-Root Growth at Low-Sucrose Conditions.

Plant roots are essential organs for absorbing nutrients from the soil or medium. Sucrose functions as a vital carbon source in root development, and sucrose starvation interferes with the redox state of plant cells. However, the mechanism of root growth at sucrose starvation remains unclear. Here, we report that SHMT1 (serine hydroxymethyltransferase 1) plays a crucial role in primary-root growth. SHMT1 mutation caused decreased sugar levels, excessive H2O2 accumulation, and severe root-growth arrest at sucrose-free conditions, whereas plants with SHMT1 overexpression had increased sugar and decreased H2O2 levels, and longer primary roots. Sucrose supply fully restored root growth of shm1-2, but CO2 alone could not, and SHMT1 is much more stable in roots than shoots at sucrose conditions, suggesting that SHMT1 accumulation in roots is critical for sucrose accumulation and root growth. Further ROS scavenging by GSH application or ROS synthesis inhibition by apocynin application or RBOHD mutation reduced H2O2 levels and partially restored the root-growth arrest phenotype of shm1-2 at low-sucrose conditions, suggesting that SHMT1 modulates root growth via sucrose-mediated ROS accumulation. Our findings demonstrated the role of SHMT1 in primary-root growth by regulating sucrose accumulation and ROS homeostasis in roots.

Experimental and Numerical Investigation into the Heat- and Mass-Transfer Processes of n-Butane Adsorption on Activated Carbon.

In this work, the adsorption parameters of n-butane vapor on an absorbent were tested following the fixed-bed method. According to the corresponding experiments, the maximum adsorption capacity and breakthrough time of activated carbon (AC) are 0.2674 g·g-1 and 924 min, respectively. According to the two-energy-state model formula and the classical adsorption heat formula, the values of theoretical and actual adsorption heat of AC adsorbing n-butane are 5.48 and 5.56 kJ·mol-1, respectively. The model for adsorption of n-butane by an AC fixed bed is based on the analytical solutions to the mass, momentum, and energy conservation equations. The model is built using porous media zone in ANSYS Fluent, the implementation of the model into ANSYS Fluent under user-defined functions (UDFs) is also described, the mass source term Si and energy source term S T are loaded into Fluent through UDF, and then the mass- and heat-transfer processes of AC in the absorption of n-butane are simulated. Furthermore, the predictions by ANSYS Fluent are compared with in situ experimental data, and the deviation rate of breakthrough time and temperature of six monitoring points is less than 5%. The results verify the accuracy and feasibility of computational fluid dynamics (CFD). Therefore, the model can be used to predict the engineering application of the adsorption of organic gases by various porous media.

Ordered clustering of single atomic Te vacancies in atomically thin PtTe2 promotes hydrogen evolution catalysis.

Exposing and stabilizing undercoordinated platinum (Pt) sites and therefore optimizing their adsorption to reactive intermediates offers a desirable strategy to develop highly efficient Pt-based electrocatalysts. However, preparation of atomically controllable Pt-based model catalysts to understand the correlation between electronic structure, adsorption energy, and catalytic properties of atomic Pt sites is still challenging. Herein we report the atomically thin two-dimensional PtTe2 nanosheets with well-dispersed single atomic Te vacancies (Te-SAVs) and atomically well-defined undercoordinated Pt sites as a model electrocatalyst. A controlled thermal treatment drives the migration of the Te-SAVs to form thermodynamically stabilized, ordered Te-SAV clusters, which decreases both the density of states of undercoordinated Pt sites around the Fermi level and the interacting orbital volume of Pt sites. As a result, the binding strength of atomically defined Pt active sites to H intermediates is effectively reduced, which renders PtTe2 nanosheets highly active and stable in hydrogen evolution reaction.

Identification of hydrophobin genes and their physiological functions related to growth and development in Pleurotus ostreatus.

Hydrophobins are small secreted proteins with important physiological functions and potential applications. Here, Pleurotus ostreatus hydrophobin genes were systematically analyzed: they were characterized, classified, and their expression profiles and gene functions were explored. In total, 40 P. ostreatus hydrophobin genes were found and showed genetic diversity, of which 15 were newly identified. The hydrophobin protein sequences were diverse but all contained eight cysteine residues with a conserved spacing pattern, and 33 of them were class I hydrophobins. The expression profile analyses showed that Vmh3 and Hydph20 were abundant in monokaryotic and dikaryotic mycelia, whereas Hydph17, Po.hyd16, Hydph8 were specifically expressed in monokaryotic mycelia and Po.hyd10 were specific in dikaryotic mycelia. Furthermore, Vmh3, Hydph20, Po.hyd7, and Po.hyd10 were abundant when dikaryotic mycelia cultivated on PDA, which are different from on substrate (Vmh2, Vmh3, Hydph7, Po.hyd3, Po.hyd7, Po.hyd9); Hydph12, POH1, and Po.hyd4 can be induced by natural light and cold stimulation during development from mycelia to primordia; Vmh3, FBH1, Hydph12, Po.hyd1-Po.hyd5, and Po.hyd8 were highly expressed in primordia and young fruiting bodies; Hydph12, Po.hyd1, Po.hyd4, and Po.hyd5 were specifically expressed in pilei. In addition, RNAi transformants of FBH1 exhibited slower growth rates and had fewer primordia and fruiting bodies, which suggests FBH1 affects the growth rate and primordia formation of P. ostreatus. Therefore, P. ostreatus hydrophobin genes belong to a large family and are temporally and spatially expressed to meet the developmental needs of mushroom.

The chemistry of gaseous benzene degradation using non-thermal plasma.

In this study, the abatement of benzene in a dielectric barrier discharge (DBD) reactor was studied. The efficiency was investigated in terms of benzene conversion and product formation. The composition of gas-liquid-solid three-phase product produced during degradation was observed by GC-MS. Under the optimal SED, the solid-phase product was analyzed by FT-IR, SEM, and EDS. The results suggested that the product were mainly benzonitriles, benzenedicarbonitrile, phenols, esters, and amides. The wt% of C in product decreased as SED increased, demonstrating that the high discharge voltage facilitated the conversion of VOCs to gaseous intermediate product and CO2. Possible degradation mechanism and pathways of benzene destruction in the DBD reactor were proposed.

Identification and physiological function of one microRNA (Po-MilR-1) in oyster mushroom Pleurotus ostreatus.

MicroRNAs are essential regulators of gene expression and have been extensively studied in plants and animals; however, few reports have been published in mushrooms. Po-MilR-1 is a novel microRNA with a length of 22 bp in Pleurotus ostreatus. The secondary structures of five precursors and the target genes of Po-MilR-1 were predicted. Expression profile analysis showed Po-MilR-1 had specific expression in the primordium and fruiting body. To explore its physiological function, Po-MilR-1 was overexpressed in P. ostreatus. The transformants showed slow mycelium growth rate and abnormal pileus with irregular edge, which suggested Po-MilR-1 plays an important role in P. ostreatus development. Additionally, Po-MilR-1 and one of its target hydrophobin genes POH1 had opposite temporal expression profiles in the primordium and fruiting body, which revealed that Po-MilR-1 may perform its physiological function through the negative regulation of POH1. This study explored the development-related function of a mushroom microRNA and will provide a reference for other microRNAs.

Surfactant-Free Synthesis of Ultrafine Pt Nanoparticles on MoS2 Nanosheets as Bifunctional Catalysts for the Hydrodeoxygenation of Bio-Oil.

Hydrodeoxygenation (HDO) of bio-oil is a crucial step for improving the bio-fuel quality, but developing highly dispersed Pt-based catalysts with high selectivity for target alkanes remains a great challenge. This study presents a fast surfactant-free method to prepare the MoS2-supported Pt catalyst for HDO. Ultrafine Pt nanoparticles with sizes of <5 nm can be readily grown on chemically exfoliated MoS2 nanosheets (NSs) via the direct microwave-assisted thermal reduction. The obtained Pt NPs/MoS2 composites show excellent catalytic performance in the conversion of palmitic acid, and the best selectivity (also the yield) of hexadecane and pentadecane is 80.56 and 19.43%, respectively.

Aldehyde dehydrogenase ALDH3F1 involvement in flowering time regulation through histone acetylation modulation on FLOWERING LOCUS C.

Flowering time regulation is one of the most important processes in the whole life of flowering plants and FLOWERING LOCUS C (FLC) is a central repressor of flowering time. However, whether metabolic acetate level affects flowering time is unknown. Here we report that ALDEHYDE DEHYDROGENASE ALDH3F1 plays essential roles in floral transition via FLC-dependent pathway. In the aldh3f1-1 mutant, the flowering time was significant earlier than Col-0 and the FLC expression level was reduced. ALDH3F1 had aldehyde dehydrogenase activity to affect the acetate level in plants, and the amino acids of E214 and C252 are essential for its catalytic activity. Moreover, aldh3f1 mutation reduced acetate level and the total acetylation on histone H3. The H3K9Ac level on FLC locus was decreased in aldh3f1-1, which reduced FLC expression. Expression of ALDH3F1 could rescue the decreased H3K9Ac level on FLC, FLC expression and also the early-flowering phenotype of aldh3f1-1, however ALDH3F1E214A or ALDH3F1C252A could not. Our findings demonstrate that ALDH3F1 participates in flowering time regulation through modulating the supply of acetate for acetyl-CoA, which functions as histone acetylation donor to modulate H3K9Ac on FLC locus.

Hermetically encapsulating sulfur by FePS3 flakes for high-performance lithium sulfur batteries.

Herein, hollow sulfur spheres encapsulated hermetically by FePS3 flakes (HSS@FePS3) are utilized in lithium sulfur batteries (LSBs). Via the encapsulation, soluble polysulfide can be trapped obviously and volume expansion during discharge can be accommodated effectively. The HSS@FePS3 cathode shows an excellent cycling stability even at a current density of 1C (a capacity decay of 0.0461% per cycle during 1000 cycles).

A Rapid and Effective Colony PCR Procedure for Screening Transformants in Several Common Mushrooms.

In the post-genomic era, gene function analysis has attracted much attention. Transformation is often needed to investigate gene function. In this study, an easy, rapid, reliable, and cost-effective colony polymerase chain reaction (PCR) method for screening mushroom transformants was developed: picking up a suitable amount of transformant's tissue (1-10 µg) to 20 µl 0.25% Lywallzyme solution, and vortexing for 10 s followed by incubation at 34 °C for 15 min. Finally, 2 µl of the suspension was used as templates to perform PCR and single target bands were successfully amplified from respective transformants of Tremella fuciformis, Pleurotus ostreatus, and Pleurotus tuber-regium. This procedure could be widely employed for screening transformants in mushroom transformation experiments.

An Enzymolysis-Assisted Agrobacterium tumefaciens-Mediated Transformation Method for the Yeast-Like Cells of Tremella fuciformis.

Agrobacterium tumefaciens-mediated transformation (ATMT), as a simple and versatile method, achieves successful transformation in the yeast-like cells (YLCs) of Tremella fuciformis with lower efficiency. Establishment of a more efficient transformation system of YLCs is important for functional genomics research and biotechnological application. In this study, an enzymolysis-assisted ATMT method was developed. The degradation degree of YLCs depends on the concentration and digestion time of Lywallzyme. Lower concentration (≤0.1%) of Lywallzyme was capable of formation of limited wounds on the surface of YLCs and has less influence on their growth. In addition, there is no significant difference of YLCs growth among groups treated with 0.1% Lywallzyme for different time. The binary vector pGEH under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter was utilized to transform the enzymolytic wounded YLCs with different concentrations and digestion time. The results of PCR, Southern blot, quantitative real-time PCR (qRT-PCR) and fluorescence microscopy revealed that the T-DNA was integrated into the YLCs genome, suggesting an efficient enzymolysis-assisted ATMT method of YLCs was established. The highest transformation frequency reached 1200 transformants per 106 YLCs by 0.05% (w/v) Lywallzyme digestion for 15 min, and the transformants were genetically stable. Compared with the mechanical wounding methods, enzymolytic wounding is thought to be a tender, safer and more effective method.

Identification and In Silico Analysis of Lectins in Gray Oyster Culinary-Medicinal Mushroom Pleurotus ostreatus (Agaricomycetes) Based on the Transcriptomes.

Lectins, one of the most important bioactive compounds, are nonimmunoglobulin proteins that can bind carbohydrates specifically. However, few reports have been published on Pleurotus ostreatus lectin at the molecular level. Hence, in this study, seven lectins were identified based on transcriptomes in four developmental stages, i.e., mycelium, primordium, young fruiting body, and mature fruiting body. The expression profiles of the lectin genes were verified by quantitative real-time PCR. Lectin2-lectin6 had the highest expression in mycelium, while lectin1 was rich in mature fruiting body, and lectin7 was in primordium. We inferred that lectin2-lectin6 may take part in cell flocculation, lectin7 was the critical gene for primordium formation, and lectinl may be involved in fruiting body maturation, respectively. By in silico analysis, all lectins were divided into three distinct groups. Lectin1-Lectin5 were about 38.5-40.7 kDa as extracellular protein and belonged to the PCL-like lectins. Lectin6 (15.4 kDa) was predicted in nucleus and belonged to fungal fruit body lectins. Lectin7 (38.5 kDa) was a member of legume-like lectins and located in the plasma membrane. This study will help us understand how lectins mediate mushroom development.

Correction: Ti2C3Tx nanosheets as photothermal agents for near-infrared responsive hydrogels.

Correction for 'Ti2C3Tx nanosheets as photothermal agents for near-infrared responsive hydrogels' by Changyu Yang et al., Nanoscale, 2018, 10, 15387-15392.

Ti2C3Tx nanosheets as photothermal agents for near-infrared responsive hydrogels.

Poly(N-isopropylacrylamide) (PNIPAM) is broadly applicable in many fields due to its temperature-induced phase transition property. Herein, a facile method to incorporate exfoliated Ti2C3Tx nanosheets in the PNIPAM network is reported. Due to compatibility, stability and photothermal properties of the incorporated Ti2C3Tx nanosheets, the obtained MXene/PNIPAM composite hydrogel shows excellent photothermal properties, expanding the pure thermal-responsive property of the PNIPAM hydrogel. Based on the smart composite hydrogel, remote light-control of the microfluidic pipeline is also demonstrated.

Rational Design of Fe/N/S-Doped Nanoporous Carbon Catalysts from Covalent Triazine Frameworks for Efficient Oxygen Reduction.

Porous organic polymers (POPs) are promising precursors for developing high performance transition metal-nitrogen-carbon (M/N/C) catalysts for the oxygen reduction reaction (ORR). The rational design of POP precursors remain a great challenge, because of the elusive structural association between the sacrificial POPs and the final M/N/C catalysts. Based on covalent triazine frameworks (CTFs), we developed a series of S-doped Fe/N/C catalysts by selecting six different aromatic nitriles as building blocks. A new mixed solvent of molten FeCl3 and S was used for CTF polymerization, which benefited the formation of Fe-Nx sites and made the subsequent pyrolysis process more convenient. Comprehensive study of these CTF-derived catalysts showed that their ORR activities are not directly dependent on the theoretical N/C ratio of the building block, but closely correlated to the ratio of the nitrile group to benzene ring (Nnitrile /Nbenzene ) and geometries of the building blocks. The high ratios of Nnitrile /Nbenzene are crucial for ORR activity of the final catalysts owing to the formation of more N-doped micropores and Fe-Nx sites in pyrolysis possess. The optimized catalyst shows high ORR performances in acid and superior ORR activity to the Pt/C catalysts under alkaline conditions.