An Efficient Chitosan/Silica Composite Core–Shell Microspheres-Supported Pd Catalyst for Aryl Iodides Sonogashira Coupling Reactions

Monodispersed chitosan/silica core–shell microspheres-supported Pd catalysts were prepared by a simple and affordable microfluidic device. Merely 5 mg of supported Pd catalyst (1 wt %) showed superior capability in Sonogashira coupling reactions between various aryl iodides and terminal alkynes in a mild environment (ligand-free, copper-free, amine-free, water–ethanol as solvent at 65 °C) even after eight cycles of use. These novel porous composite microspheres provide a new carrier to reduce the loading, enhance the activity, and increase the stability of noble metal catalyst

An Efficient Chitosan/Silica Composite Core–Shell Microspheres-Supported Pd Catalyst for Aryl Iodides Sonogashira Coupling Reactions

Monodispersed chitosan/silica core–shell microspheres-supported Pd catalysts were prepared by a simple and affordable microfluidic device. Merely 5 mg of supported Pd catalyst (1 wt %) showed superior capability in Sonogashira coupling reactions between various aryl iodides and terminal alkynes in a mild environment (ligand-free, copper-free, amine-free, water–ethanol as solvent at 65 °C) even after eight cycles of use. These novel porous composite microspheres provide a new carrier to reduce the loading, enhance the activity, and increase the stability of noble metal catalyst

Zinc Oxide Nanoclusters Encapsulated in MFI Zeolite as a Highly Stable Adsorbent for the Ultradeep Removal of Hydrogen Sulfide

Often, trace impurities in a feed stream will cause failures in industrial applications. The efficient removal of such a trace impurity from industrial steams, however, is a daunting challenge due to the extremely small driving force for mass transfer. The issue lies in an activity–stability dilemma, that is, an ultrafine adsorbent that offers a high exposure of active sites is favorable for capturing species of a low concentration, but free-standing adsorptive species are susceptible to rapidly aggregating in working conditions, thus losing their intrinsic high activity. Confining ultrafine adsorbents in a porous matrix is a feasible solution to address this activity–stability dilemma. We herein demonstrate a proof of concept by encapsulating ZnO nanoclusters into a pure-silica MFI zeolite (ZnO@silicalite-1) for the ultradeep removal of H2S, a critical need in the purification of hydrogen for fuel cells. The Zn species and their interaction with silicalite-1 were thoroughly investigated by a collection of characterization techniques such as HADDF-STEM, UV–visible spectroscopy, DRIFTS, and 1H MAS NMR. The results show that the zeolite offers rich silanol defects, which enable the guest nanoclusters to be highly dispersed and anchored in the silicious matrix. The nanoclusters are present in two forms, Zn(OH)+ and ZnO, depending on the varying degrees of interaction with the silanol defects. The ultrafine nanoclusters exhibit an excellent desulfurization performance in terms of the adsorption rate and utilization. Furthermore, the ZnO@silicalite-1 adsorbents are remarkably stable against sintering at high temperatures, thus maintaining a high activity in multiple adsorption–regeneration cycles. The results demonstrate that the encapsulation of active metal oxide species into zeolite is a promising strategy to develop fast responsive and highly stable adsorbents for the ultradeep removal of trace impurities

The auxotroph of the mutants can be satisfied by addition of the intermediate 2-KIC.

<p>Mycelial morphology of the wild-type PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C cultured on FGA medium amended with 2-KIC at different concentrations indicated in the figure at 25°C for 2 days.</p

<i>FgLEU2A</i> is involved in adaptation to various cellular stresses in <i>F</i>. <i>graminearum</i>.

<p>Comparisons of mycelial inhibition percentages of each strain grown on YEPD medium amended with various cellular stresses at concentrations described in the figure and line bars in each column denote standard errors of three repeated experiments.</p

Different roles of <i>FgLEU2A</i> and <i>FgLEU2B</i> in Leu biosynthesis in <i>F</i>. <i>graminearum</i>.

<p>Mycelial morphology of the wild-type PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C cultured on FGA medium amended with Leu at different concentrations indicated in the figure at 25°C for 2 days.</p

Two <i>FgLEU2</i> Genes with Different Roles in Leucine Biosynthesis and Infection-Related Morphogenesis in <i>Fusarium graminearum</i>

<div><p>3-isopropylmalate dehydrogenase (IPMD) encoded by <i>LEU2</i> is a key enzyme in leucine (Leu) biosynthetic pathway. Analysis of the genome sequence of <i>Fusarium graminearum</i> revealed two paralogous <i>LEU2</i> genes (designated as <i>FgLEU2A</i> and <i>FgLEU2B</i>) in this fungus and the deduced amino acid sequences of FgLeu2A and FgLeu2B share 45% identity. Targeted disruption of individual <i>FgLEU2A/B</i> gene in <i>F</i>. <i>graminearum</i> assigned a more crucial role of FgLeu2A in Leu biosynthesis as disruption of <i>FgLEU2A</i> resulted in mutant (ΔFgLeu2A-10) that was Leu-auxotrophic and could not grow in minimal medium limited for amino acids, whereas <i>FgLEU2B</i> deletion mutant ΔFgLeu2B-2 was morphologically indistinguishable from the wild type strain PH-1. The growth defects of ΔFgLeu2A-10 could be overcome by exogenous addition of Leu at 0.25 mM. Double deletion of <i>FgLEU2A</i> and <i>FgLEU2B</i> (ΔFgLeu2AB-8) caused a more severe Leu-auxotrophic phenotype as the concentration of Leu exogenously added to medium to rescue the growth defect of ΔFgLeu2AB-8 should be raised to 1.25 mM, indicating a less important but nonnegligible role of FgLeu2B in Leu biosynthesis. Disturb of Leu biosynthesis caused by <i>FgLEU2A</i> deletion leads to slower growth rate, reduced aerial hyphal formation and red pigmentation on PDA plates and completely blocked conidial production and germination. All of the defects above could be overcome by Leu addition or complementation of the full-length <i>FgLEU2A</i> gene. ΔFgLeu2A-10 also showed significantly increased sensitivity to osmotic and oxidative stresses. Pathogenicity assay results showed that virulence of mutants lacking <i>FgLEU2A</i> were dramatically impaired on wheat heads and non-host cherry tomatoes. Additionally, a low level of deoxynivalenol (DON) production of ΔFgLeu2A-10 and ΔFgLeu2AB-8 in wheat kernels was also detected. Taken together, results of this study indicated a crucial role of FgLeu2A and a less important role of FgLeu2B in Leu biosynthesis and fungal infection-related morphogenesis in <i>F</i>. <i>graminearum</i> and FgLeu2A may serve as a potential target for novel antifungal development.</p></div

<i>FgLEU2A</i> is important for full virulence of <i>F</i>. <i>graminearum</i>.

<p><b>A</b> Flowering wheat heads were point inoculated with a conidial suspension at 10⁵ conidia/ml of the wild type strain PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C and infected wheat heads were photographed 10 days after inoculation. <b>B</b> Cherry tomatoes were inoculated with a conidial suspension at 10⁵ conidia/ml of each strain and infected fruits were photographed 3 days after inoculation.</p

<i>FgLEU2A</i> is involved in conidial formation and germination in <i>F</i>. <i>graminearum</i>.

<p><b>A</b> Comparison of conidiation among PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C in MBL amended with or without Leu. Line bars in each column denote standard errors of three repeated experiments. <b>B</b> Conidia of PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C harvested from MBL supplemented with 1.25 mM Leu were re-suspended in 2% sucrose solution and cultured at 25°C for 4h and 6h with or without addition of Leu. Germination rate of each strain was calculated and line bars in each column denote standard errors of three repeated experiments.</p

<i>FgLEU2A</i> is required for DON biosynthesis of <i>F</i>. <i>graminearum</i>.

<p>The amounts of DON (mg/mg ergosterol) produced by the wild type strain PH-1, ΔFgLeu2A-10, ΔFgLeu2B-2, ΔFgLeu2AB-8 and ΔFgLeu2A-8C in infected wheat kernels and bars denote standard errors from three repeated experiments.</p