Design, Synthesis, and Antifungal Activities of Novel Pyrazole-4-carboxamide Derivatives Containing an Ether Group as Potential Succinate Dehydrogenase Inhibitors.

A series of novel pyrazole-4-carboxamides bearing an ether group were designed and synthesized on the basis of the structure of commercial succinate dehydrogenase inhibitor (SDHI) fungicide flubeneteram via scaffold hopping and evaluated for their antifungal activities against five fungi. The bioassay results showed that most of the target compounds exhibited excellent in vitro antifungal activity against Rhizoctonia solani and some compounds exerted remarkable antifungal activities against Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium graminearum, and Alternaria alternate. Particularly, compounds 7d and 12b displayed outstanding antifungal activity against R. solani, with an EC50 value of 0.046 µg/mL, far superior to that of boscalid (EC50 = 0.741 µg/mL) and fluxapyroxad (EC50 = 0.103 µg/mL). Meanwhile, compound 12b also presented a broader fungicidal spectrum than other compounds. Moreover, in vivo anti-R. solani results showed that compounds 7d and 12b could significantly inhibit the growth of R. solani in rice leaves with excellent protective and curative efficacies. In addition, the results of the succinate dehydrogenase (SDH) enzymatic inhibition assay showed that compound 7d generated significant SDH inhibition, with an IC50 value of 3.293 µM, which was about 2 times better than that of boscalid (IC50 = 7.507 µM) and fluxapyroxad (IC50 = 5.991 µM). Furthermore, scanning electron microscopy (SEM) analysis indicated that compounds 7d and 12b significantly destroyed the typical structure and morphology of R. solani hyphae. The molecular docking study revealed that compounds 7d and 12b could embed into the binding pocket of SDH and form hydrogen bond interactions with TRP173 and TRY58 at the activity site of SDH, which was in line with fluxapyroxad, indicating that they had a similar mechanism of action. These results demonstrated that compounds 7d and 12b could be promising candidates of SDHI fungicides, which deserved further investigation.

Multi-scale hybrid spherical graphite composites: a light weight thermal interface material with high thermal conductivity and simple processing technology.

In consideration of low density and high intrinsic thermal conductivity, spherical graphite powders can act as promising fillers for light weight thermal interface materials. Herein, spherical artificial graphite derived composites exhibit a similar thermal conductivity and significantly reduced bulk density compared with traditional Al2O3-derived composites. Further, based on the particle packing theory, an innovatively optimized calculation method has been proposed by introducing the quadratic programming method into the traditional calculation method to acquire the optimum formulation of multi-scale spherical graphite particles. The thermal conductivity of the optimum formulation-derived composites attains 1.994 W m-1 K-1, which is 1.72 times higher than that of the single particle size-derived composites (1.156 W m-1 K-1), accompanied by a low density of 1.812 g cm-3 vs. the 2.31 g cm-3 of the traditional Al2O3-derived composites. Besides, the relationships between the tap density of the graphite powders, thermal conductivity and maximum filling content of the composites are creatively established, which are available for predicting the thermal conductivities of composites by simply testing the tap density of the fillers. This present work provides an instructional strategy to optimize spherical filler particles for thermal management of electronic devices.

[Construction of SPA7074-deficient mutant of biocontrol strain Streptomyces pactum Act12 and characterization of its secondary metabolites].

Objective: To disrupt spa7074, which encodes a member of the TetR family transcriptional factors, in biocontrol strain Act12 and characterize the secondary metabolites in the mutant strain. Methods: We disrupted the gene spa7074 by homologous recombination. The secondary metabolites of the mutant strain Δspa7074 and Act12 were detected by HPLC. The structure was analyzed by MS and NMR. Results: Compared to the wild-type strain, the production of some unknown compounds in the mutant strain Δspa7074 increased obviously. We purified one of the compounds and identified as oligomycin D by MS and NMR analysis. Conclusion: An oligomycin D-producing strain Δspa7074 was derived via genetic engineering.