Validamycin A Enhances the Interaction Between Neutral Trehalase and 14-3-3 Protein Bmh1 in Fusarium graminearum.

In agriculture, Trehalase is considered the main target of the biological fungicide validamycin A, and the toxicology mechanism of validamycin A is unknown. 14-3-3 proteins, highly conserved proteins, participate in diverse cellular processes, including enzyme activation, protein localization, and acting as a molecular chaperone. In Saccharomyces cerevisiae, the 14-3-3 protein Bmh1could interact with Nth1 to respond to specific external stimuli. Here, we characterized FgNth, FgBmh1, and FgBmh2 in Fusarium graminearum. ΔFgNth, ΔFgBmh1, and ΔFgBmh2 displayed great growth defects and their peripheral tips hyphae generated more branches when compared with wild-type (WT) PH-1. When exposed to validamycin A as well as high osmotic and high temperature stresses, ΔFgNth, ΔFgBmh1, and ΔFgBmh2 showed more tolerance than WT. Both ΔFgNth and ΔFgBmh1 displayed reduced deoxynivalenol production but opposite for ΔFgBmh2, and all three deletion mutants showed reduced virulence on wheat coleoptiles. In addition, coimmunoprecipitation (Co-IP) experiments suggested that FgBmh1 and FgBmh2 both interact with FgNth, but no interaction was detected between FgBmh1 and FgBmh2 in our experiments. Further, validamycin A enhances the interaction between FgBmh1 and FgNth in a positive correlation under concentrations of 1 to 100 µg/ml. In addition, both high osmotic and high temperature stresses promote the interaction between FgBmh1 and FgNth. Co-IP assay also showed that neither FgBmh1 nor FgBmh2 could interact with FgPbs2, a MAPKK kinase in the high-osmolarity glycerol pathway. However, FgBmh2 but not FgBmh1 binds to the heat shock protein FgHsp70 in F. graminearum. Taken together, our results demonstrate that FgNth and FgBmh proteins are involved in growth and responses to external stresses and virulence; and validamycin enhanced the interaction between FgNth and FgBmh1in F. graminearum.

A new point mutation in ß2-tubulin confers resistance to carbendazim in Fusarium asiaticum.

Resistance to benzimidazole fungicides in many phytopathogenic fungi is caused by specific point mutations in the ß-tubulin gene (ß-tubulin). However, the mutated locus and genotype of ß-tubulin differ among phytopathogenic fungi. To validate the point mutation in Fusarium asiaticum ß2-tubulin that confers resistance to carbendazim and to analyze the molecular interaction between carbendazim and F. asiaticum ß2-tubulin. In this study, a new point mutation (GAG→GCG, E198A) at codon 198 of ß2-tubulin in a wild-type F. asiaticum strain was constructed by site-directed mutagenesis followed by a split marker strategy. The site-directed mutants were verified and exhibited a high level of resistance to carbendazim. In the absence of fungicide treatment, the biological characteristics did not differ between the site-directed mutants and the wild-type strain. Molecular docking between carbendazim and ß2-tubulin was carried out using the Surflex-Dock program in Sybyl X-2.0 version and the results indicated that the E198A mutation altered the configuration of ß2-tubulin, resulting in the change of the bonding sites and docking scores. We concluded that the point mutation of F. asiaticum ß2-tubulin conferring carbendazim resistance may not always be the bonding site for carbendazim.

[Investigation of the Interaction between 1,3-Dimethylurea and Solvent by Raman Methods].

Urea family plays significant role in the bio-science area. Because of the unique frame, they can form Hydrogen bond with water as well as other substance. Hydrogen bonds are normal weak interactions in the system of bio-molecules. A Raman spectrum is the most powerful method to obscure the Hydrogen bond interaction between molecules. Initially, we measure the Raman spectra of DMU crystal, and then use density function theory with a B3LYP/6-311G* * basis set to optimize the geometry structure and calculate the vibrational frequency of gas phase DMU, which assigns the Raman pecks. Then, measure the solvent. When dissolving DMU in water, the interaction between DMU-DMU will replaced by the interaction between water-DMU. The orbital hybridization of nitrogen atoms changes from the solid-state the sp' orbital hybridization to sp3. So, the frame of this molecule goes from in-planet to out of plant during this process.

Twisted Structure and Multiple Charge-Transfer Channels Endow Thermally Activated Delayed Fluorescence Devices with Small Efficiency Roll-Off and Low Concentration Dependence.

Despite the rapid development of thermally activated delayed fluorescent (TADF) materials, developing organic light-emitting diodes (OLEDs) with small efficiency roll-off remains a formidable challenge. Herein, we have designed a TADF molecule (mClSFO) based on the spiro fluorene skeleton. The highly twisted structure and multiple charge-transfer channels effectively suppress aggregation-caused quenching (ACQ) and endow mClSFO with excellent exciton dynamic properties to reduce efficiency roll-off. Fast radiative rate (kr) and rapid reverse intersystem crossing (RISC) rate (kRISC) of 1.6 × 107 s-1 and 1.07 × 106 s-1, respectively, are obtained in mClSFO. As a result, OLEDs based on mClSFO obtain impressive maximum external quantum efficiency (EQEmax) exceeding 20% across a wide doping concentration range of 10-60 wt%. 30 wt% doped OLED exhibits an EQEmax of 23.1% with a small efficiency roll-off, maintaining an EQE of 18.6% at 1000 cd m-2. The small efficiency roll-off and low concentration dependence observed in the TADF emitter underscore its significant potential.

Extended Conjugation Strategy Enabling Red-Shifted and Efficient Emission of Orange-Red Thermally Activated Delayed Fluorescence Materials.

In account of the energy gap law, the development of efficient narrow-band gap thermally activated delayed fluorescence (TADF) materials remains a major challenge for the application of organic light-emitting diodes (OLEDs). The orange-red TADF materials are commonly designed with either large π-conjugated systems or strong intramolecular donor-acceptor (D-A) interactions for red-shift emission and small singlet-triplet energy gap (ΔEST). There are rare reports on the simultaneous incorporation of these two strategies on the same material systems. Herein, two orange-red emitters named 1P2D-BP and 2P2D-DQ have been designed by extending the conjugation degree of the center acceptor DQ and increasing the number distribution of the peripheral donor PXZ units, respectively. The emission peak of 1P2D-BP is red-shifted to 615 nm compared to 580 nm for 2P2D-DQ, revealing the pronounced effect of the conjugation extension on the emission band gap. In addition, the distorted molecular structure yields a small ΔEST of 0.02 eV, favoring the acquisition of a high exciton utilization through an efficient reverse intersystem crossing process. As a result, orange-red OLEDs with both 1P2D-BP and 2P2D-DQ have achieved an external quantum efficiency (EQE) of more than 17%. In addition, the efficient white OLED based on 1P2D-BP is realized through precise exciton assignment and energy transport modulation, showing an EQE of 23.6% and a color rendering index of 82. The present work provides an important reference for the design of high-efficiency narrow-band gap materials in the field of solid-state lighting.