Sustainable and Selective Monomethylation of Anilines by Methanol with Solid Molecular NHC-Ir Catalysts

Using feedstock methanol as a green methylation reagent, the selective <i>N-</i>monomethylation of anilines is realized under mild reaction conditions by using N-heterocyclic carbene iridium (NHC-Ir) coordination assemblies as highly efficient solid molecular catalysts. Along with a broad substrate scope and good functional group tolerance, up to quantitative yield and 2.0 × 10⁴ turnover numbers (TONs) are obtained even at low catalyst loadings. Notably, the solid NHC-Ir molecular catalyst can be easily recovered and recycled more than 20 times without obvious loss of reactivity and selectivity. Furthermore, this selective practical protocol can be successfully extended to direct methylation of highly functionalized bioactive compounds including 3-aminoestrone, cinacalcet, and their analogues in excellent yields and selectivities, highlighting their potential application in pharmaceuticals

Tuning the Photocatalytic Activity of Graphitic Carbon Nitride by Plasma-Based Surface Modification

In this study, we demonstrate that plasma treatment can be a facile and environmentally friendly approach to perform surface modification of graphitic carbon nitride (g-CN), leading to a remarkable modulation on its photocatalytic activity. The bulk properties of g-CN, including the particle size, structure, composition, and electronic band structures, have no changes after being treated by oxygen or nitrogen plasma; however, its surface composition and specific surface area exhibit remarkable differences corresponding to an oxygen functionalization induced by the plasma post-treatment. The introduced oxygen functional groups play a key role in reducing the recombination rate of the photoexcited charge carries. As a consequence, the oxygen-plasma-treated sample shows a much superior photocatalytic activity, which is about 4.2 times higher than that of the pristine g-CN for the degradation of rhodamine B (RhB) under visible light irradiation, while the activity of nitrogen-plasma-treated sample exhibits a slight decrease. Furthermore, both of the plasma-treated samples are found to possess impressive photocatalytic stabilities. Our results suggest that plasma treatment could be a conventional strategy to perform surface modification of g-CN in forms of both powders and thin films, which holds broad interest not only for developing g-CN-based high-performance photocatalysts but also for constructing photoelectrochemical cells and photoelectronic devices with improved energy conversion efficiencies

Generation and Characterization of the Western Regional Research Center Brachypodium T-DNA Insertional Mutant Collection

<div><p>The model grass <i>Brachypodium distachyon</i> (<i>Brachypodium</i>) is an excellent system for studying the basic biology underlying traits relevant to the use of grasses as food, forage and energy crops. To add to the growing collection of <i>Brachypodium</i> resources available to plant scientists, we further optimized our <i>Agrobacterium tumefaciens</i>-mediated high-efficiency transformation method and generated 8,491 <i>Brachypodium</i> T-DNA lines. We used inverse PCR to sequence the DNA flanking the insertion sites in the mutants. Using these flanking sequence tags (FSTs) we were able to assign 7,389 FSTs from 4,402 T-DNA mutants to 5,285 specific insertion sites (ISs) in the <i>Brachypodium</i> genome. More than 29% of the assigned ISs are supported by multiple FSTs. T-DNA insertions span the entire genome with an average of 19.3 insertions/Mb. The distribution of T-DNA insertions is non-uniform with a larger number of insertions at the distal ends compared to the centromeric regions of the chromosomes. Insertions are correlated with genic regions, but are biased toward UTRs and non-coding regions within 1 kb of genes over exons and intron regions. More than 1,300 unique genes have been tagged in this population. Information about the Western Regional Research Center <i>Brachypodium</i> insertional mutant population is available on a searchable website (<a href="http://brachypodium.pw.usda.gov" target="_blank">http://brachypodium.pw.usda.gov</a>) designed to provide researchers with a means to order T-DNA lines with mutations in genes of interest.</p></div

Flanking sequence tags (FSTs) generated for T-DNA lines.

<p>Flanking sequence tags (FSTs) generated for T-DNA lines.</p

Sequences and locations of primers used for Inverse PCR.

<p>Sequences and locations of primers used for Inverse PCR.</p

Expression of <i>FT</i>-like genes in <i>FT1</i>_HOPE transgenic wheat.

<p>The experiment was performed on transgenic lines (<i>FT1</i>_HOPE) and the non-transgenic control Jagger. Leaf tissues were collected from two independent experiments, including plants grown under a (A) LD photoperiod for five weeks and (B) plants grown under a SD photoperiod for six weeks. <i>ACTIN</i> was used as the internal control. Samples were harvested at 10∶00 a.m. Asterisks indicate <i>P</i> values: * = <i>P</i><0.05, ** = <i>P</i><0.01, *** = <i>P</i><0.001.</p

IPCR strategy for obtaining T-DNA flanking sequences.

<p>The diagram illustrates the IPCR strategy used to obtain sequences flanking the T-DNA insertion sites (ISs). Restriction enzymes (shown as scissors) with recognition sites (black lines) near the T-DNA border sequences (LB and RB) were used to digest DNA from T-DNA insertion lines. Enzymes cut both within the T-DNA and genomic sequence, and ligations were performed to circularize purified digestion products. PCR of the ligation products was performed using T-DNA specific primers and sequencing was performed with nested primers. The orientations and locations of primers with respect to restriction sites are shown as black arrows. Primers located within the T-DNA directed toward the junction with genomic DNA are designated T primers (LB-T and RB-T). Sequencing reactions using these primers return genomic sequence directly adjacent to the IS (dark blue dotted arrows). Primers directed into the T-DNA are designated RE primers (LB-RE and RB-RE). After enzyme digestion and ligation, sequencing reactions using these primers return genomic sequence starting from the closest restriction enzyme recognition site within the <i>Brachypodium</i> genomic sequence and directed toward the T-DNA insertion (light blue dotted arrows).</p

<i>FT1</i> overexpression promotes floral organogenesis.

<p>(A–C) <i>Brachypodium 35S::BdFT1:GFP</i>, (A) Shoot regeneration of non-transgenic control calli (B) direct spike formation from transformed calli and (C) rudimentary leaves associated with spikelet formation from transformed calli. (D–F) Wheat <i>Ubi::cFT-B1</i>. (D) Cluster of florets surrounded by rudimentary leaves in a transformed callus. (E) Different floral organs: lemma (Le), palea (Pa), pistil (Pi) and stamen (St). The additional organs seem to be glumes but it was difficult to determine because of the close clustering of multiple florets. (F) Anther with regions of non-viable pollen (blue color after pollen staining).</p

Restriction enzymes and primers used for Inverse PCR.

<p>Restriction enzymes and primers used for Inverse PCR.</p

Transcript levels of target genes in transgenic T₁ wheat RNAi plants and the non-transgenic wheat control.

<p>(A) Comparison between the average of five transgenic plants (RNAi) and the wild type control using contrasts. (B–G) Comparison between individual transgenic lines and wild type using Dunnett’s test. (B) <i>FT1</i>, (C) <i>FT2</i>, (D) <i>FT3</i>, (E) <i>FT4</i>, (F) <i>FT5</i>, (G) <i>VRN1</i> (gene regulated by <i>FT1</i>). <i>ACTIN</i> was used as the internal control. Samples were harvested at 4∶00 p.m., when the wild type controls began to flower. Asterisks indicate <i>P</i> values: * = <i>P</i><0.05, ** = <i>P</i><0.01, *** = <i>P</i><0.001.</p