Insight into CO activation over Cu(100) under electrochemical conditions

The reduction of CO2 on copper electrodes has attracted great attentions in the last decades, since it provides a sustainable approach for energy restore. During the CO2 reduction process, the electron transfer to COads is experimentally suggested to be the crucial step. In this work, we examine two possible pathways in CO activation, i.e. to generate COHads and CHOads, respectively, by performing the state-of-the-art constrained ab initio molecular dynamics simulations on the charged Cu(100) electrode under aqueous conditions, which is close to the realistic electrochemical condition. The free energy profile in the formation of COHads via the coupled proton and electron transfer is plotted. Furthermore, by Bader charge analyses, a linear relationship between C-O bond distance and the negative charge in CO fragment is unveiled. The formation of CHOads is identified to be a surface catalytic reaction, which requires the adsorption of H atom on the surface first. By comparing these two pathways, we demonstrate that kinetically the formation of COHads is more favored than that of CHOads, while CHOads is thermodynamically more stable. This work reveals that CO activation via COHads intermediate is an important pathway in electrocatalysis, which could provide some insights into CO2 electroreduction over Cu electrodes

نقش بمبزين در سيری پيش از جذب

پس از صرف غذا و پيش از آنکه مواد غذايی هضم و جذب شوند، دريافت غذا بسرعت وقفه می يابد و انسان احساس سيری می کند. اين موضوع نشان می دهد که اطلاعات مربوط به اعصاب حسی يا مواد هورمونی مترشحه از بخش های فوقانی لوله گوارش موجب سيری پيش از جذب می شود. بعضي نوروترانسميترها و مواد هورمونی به عنوان عوامل فرضی سيری شناخته شده اند که يکی از آنها بمبزين است. بمبزين اعمال يک نوروترانسميتر را در تشکيلات عصبی لوله گوارش پستانداران Bombesin تقليد می کند. بمبزين به کار رفته در بطن های جانبی مغز با فعال کردن سوبستراهای عصبی پاراونتريکولار موجب وقفه دريافت غذا و هيپوانسولينمی می گردد. با تزريق داخل صفاتی بمبزين نه تنها ميزان دريافت غذا کاهش (Gastrin Releasing) GBP می يابد بلکه فاصله بين غذا نيز افزايش می يابد. بعلاوه بمبزين و سبب آزاد شدن هورمونهايی در روده می شوند که اين مواد خود بعنوان عوامل بروز سيری Peptide عمل می کنن

Phosphine-Catalyzed Asymmetric (3+2) Annulations of δ‑Acetoxy Allenoates with 2‑Naphthols

Phosphine-catalyzed (3+2) annulations of δ-acetoxy allenoates with 2-naphthols are reported, wherein the δC of allentoate reacts with the αC of 2-naphthol to form the C–C bond while a C–O bond is formed between the γC of allenoate and the hydroxyl group of 2-naphthol. When (R)-SITCP is used as the catalyst, 1,2-dihydronaphtho­[2,1-<i>b</i>]­furans are obtained in moderate to good yields and with high enantioselectivity. This method is useful for the construction of enantiomerically enriched atropoisomeric furans via a central to axial chirality conversion strategy

Biological and molecular characterization of <i>Zucchini yellow mosaic virus</i> isolates infecting melon in Xinjiang, China

<p><i>Zucchini yellow mosaic virus</i> (ZYMV) causes one of the most destructive diseases of cucurbits worldwide. Although the virus has been present in China for more than 25 years, there is little information about biological and molecular traits of ZYMV isolates from China. This study aimed to characterize 26 ZYMV isolates from Xinjiang, China based on pathotypes, molecular variability and host range. Phylogenetic analysis of the complete sequences of the coat protein gene revealed three distinct groups (A, B and C), with four subgroups in A (I–IV). All isolates from Xinjiang were placed in group C and subgroups A–I and A–II. To test for differences in host range among different phylogenetic groups from Xinjiang, 13 isolates were mechanically inoculated onto 14 plant species in five families and their pathotypes were also identified based on the reaction of a resistant melon accession PI414723. Overall, the results showed that there were no correlations of host responses to inoculation with ZYMV isolates from different phylogenetic groups. However, on <i>Cucurbita pepo</i>, differences in host responses to inoculation with the ZYMV isolates from different phylogenetic groups were observed. Although the host range of the 13 isolates tested was similar, their biological properties on different hosts were slightly different from the ZYMV isolates characterized in other countries. The results of the pathotype test showed that the 13 ZYMV isolates were classified as pathotype 0. The information obtained is important in breeding for resistant varieties.</p

Copper-Catalyzed, Stereoselective Cross-Coupling of Cyclic Allyl Boronic Acids with α‑Diazoketones

In this study, we present the synthesis of new, stereodefined allylboronic acids employed to investigate the stereochemistry of the Cu-catalyzed cross-coupling of allylboronic acids with α-diazoketones. According to our results, this reaction proceeds with retention of the relative configuration of the allylboronic acid substrate. We suggest that the stereoinduction step involves a <i>syn</i> S_E2′-type transmetalation of the allylboronic acid substrate with a Cu–carbene species

Defects in WRKY70 and WRKY54 Result in SA Overaccumulation

<div><p>(A) Plants were dipped in either a 10 mM MgCl₂ solution or a suspension of <i>Psm</i> ES4326 <i>avrRpt2</i> to trigger SA production. Free SA was extracted and measured from three samples for each datapoint 3 dpi. Error bars represent SDs. This experiment was repeated twice with similar results.</p><p>(B) The SA biosynthesis gene <i>ICS1</i> is upregulated in the <i>wrky54 wrky70</i> (<i>w54 w70</i>) double mutant. Relative transcript levels were determined by RT-qPCR after normalization to ubiquitin. Error bars represent SD from three PCR runs.</p><p>(C) Lack of resistance in <i>w54 w70</i>, measured by bacterial growth 3 dpi with a high dose of <i>Psm</i> ES4326.</p><p>(D and E) The <i>wrky53 wrky70</i> (<i>w53 w70</i>) double mutant displays an EDS phenotype. Bacterial growth was measured in 3 dpi (D) and disease symptoms were recorded in 3 dpi (E).</p><p>Both (C) and (D) were done three times each with similar results.</p></div

Resistance Defects of <i>wrky58</i>

<p>(A) Loss of WRKY58 confers resistance when plants were weakly induced with 30 mM BTH. (B) To examine the function of WRKY58, the <i>wrky58</i> mutation was introduced into <i>wrky18,</i> and the effect was observed in an EDS test 3 dpi. <i>w18 w58</i> represents the <i>wrky18 wrky58</i> double mutant. Both (A) and (B) were performed twice with similar results.</p

Resistance Defects of <i>wrky18</i>

<div><p>(A) Plants were chemically induced with 60 μM BTH 24 h before inoculation with a high dose of <i>Psm</i> ES4326 (OD₆₀₀ = 0.001). As a control, uninduced plants were inoculated at the same time. Bacterial growth was scored 3 dpi. Each datapoint represents the average colony-forming units (cfu) from 16 leaf disks plotted on a log scale, with error bars indicating 95% confidence intervals. This experiment was repeated more than five times with similar results.</p><p>(B) Plants were first inoculated with either P. syringae pv. <i>phaseolicola avrB</i> or 10 mM MgCl₂ on two lower leaves. Later (3 d), three upper leaves were inoculated with <i>Psm</i> ES4326 (OD₆₀₀ = 0.001). Leaf disks from the second inoculation were collected 3 dpi to measure bacterial growth. This experiment was carried out twice with similar results.</p><p>(C and D) To examine <i>wrky18</i> for an EDS phenotype, plants were inoculated with a low dose of <i>Psm</i> ES4326 (OD₆₀₀ = 0.0001). Bacterial growth was measured in 3 dpi (C), and disease symptoms were recorded in (D) 3 dpi. These experiments were performed more than five times with similar results.</p></div

Induction of <i>WRKY</i> Genes by SAR Inducers and NPR1

<p>Plotted here are log₂-transformed microarray data normalized by the GeneSpring package, showing the expression levels of six WRKY genes 0, 8, and 24 h after BTH treatment in WT (<i>NPR1</i> +) and <i>npr1</i> mutant (<i>NPR1</i> −). The expression levels of <i>WRKY59</i> and <i>WRKY66</i> were too low to be detected under these conditions. Error bars represent standard deviations (SDs).</p

Genes Affected by BTH, <i>npr1,</i> and <i>wrky18</i> 0, 8, and 24 h after Induction

<div><p>Using ANOVA, the expression of 6,525 genes was found to be altered in WT following BTH treatment (<i>p</i> < 0.05) (after multiple testing correction using the method proposed by Benjamini and Hochberg to assess false discovery rate [<a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.0020123#ppat-0020123-b022" target="_blank">22</a>]). After applying a 2-fold change cutoff to these genes, the list was reduced to 2,280 genes, among which 1,147 were induced and 1,133 were repressed. From this list, a two-way ANOVA was applied between WT and <i>npr1</i> data sets and between WT and <i>wrky18</i> data sets to identify NPR1-dependent and WRKY18-dependent genes, respectively.</p><p>(A) The Venn diagram shows that almost all BTH-responsive genes were NPR1-dependent (2,248/2,280; 99%) whereas the expression of 451 BTH-responsive genes (∼19.8%) was altered in the <i>wrky18</i> mutant.</p><p>(B) The expression levels of 2,280 BTH-dependent genes normalized by GeneSpring were plotted on log scale on the <i>y</i>-axis and in time order on the <i>x</i>-axis. Genes induced and repressed in WT are colored red and green, respectively. The profile of these genes in the <i>npr1</i> mutant is also depicted.</p><p>(C) The expression levels of 451 WRKY-dependent genes in WT and in <i>wrky18</i> mutant were normalized by GeneSpring and plotted on log scale on the <i>y</i>-axis and in time order on the <i>x</i>-axis. Genes induced and repressed in WT are colored red and green, respectively. The majority of them showed either diminished induction (204 genes) or diminished repression (152 genes) in <i>wrky18,</i> in contrast to the robust response in WT and the almost complete lack of response in <i>npr1.</i></p></div