Design, Synthesis, and Antifungal Activity of Some Novel Phenylthiazole Derivatives Containing an Acylhydrazone Moiety.

Crop fungal diseases pose a serious threat to global crop production and quality. Developing new and efficient fungicides is an important measure to control crop diseases. Phenylthiazole was found to be an excellent antifungal skeleton based on our previous study on the structural optimization and biological activity of the natural product thiasporine A. To find new fungicides, 45 phenylthiazole derivatives containing an acylhydrazone moiety were designed and synthesized by the principle of active substructure splicing. Forty-two of the forty-five compounds are novel, except for compounds E1, E14, and E33. Their structures were structurally characterized by 1H NMR, 13C NMR, and HRMS. The antifungal activities of the target compounds against Magnaporthe oryzae Colletotrichum camelliaet, Bipolaris maydis, and Sclerotinia sclerotiorum were evaluated at 25 µg/mL. The bioassay results revealed that most of these compounds exhibited excellent antifungal activities against M. oryzae and C. camelliaet at 25 µg/mL. In particular, compounds E4, E10, E14, E17, E23, E26, and E27 showed the inhibition rate of more than 80% against M. oryzae, with EC50 values of 1.66, 2.01, 2.26, 1.45, 1.50, 1.29, and 2.65 µg/mL, respectively, which were superior to that of the commercial fungicides Isoprothiolane (EC50 = 3.22 µg/mL) and Phenazine-1-carboxylic acid (EC50 = 27.87 µg/mL). The preliminary structure-activity relationship (SAR) results suggested that introducing methyl, halogen, or methoxy at the ortho-position of R1 and the para-position of R2 can endow the final structure with excellent antifungal activity against M. oryzae. The current results provide useful data for developing phenylthiazole derivatives as new fungicides for controlling rice blast caused by M. oryzae.

Novel supramolecular elastomer films based on linear carboxyl-terminated polydimethylsiloxane oligomers: preparation, characterization, biocompatibility, and application in wound dressings.

A novel supramolecular elastomer (SESi) based on multiple hydrogen bond associations between low-molecular-weight polydimethylsiloxane chains was obtained through a two-step reaction of linear carboxyl-terminated polydimethylsiloxane oligomers with diethylenetriamine and urea, and the reaction mechanism was characterized. The results of differential scanning calorimetry and X-ray diffraction analyses indicated that the supramolecular network structure is completely amorphous, endowing SESi with rubber-like elastic behavior at room temperature. The transparent SESi film prepared by hot pressing displayed nice viscoelasticity, benign water absorption, water vapor transition rates, and ideal biocompatibility; and did not show cytotoxicity or skin irritation. These properties allow the elastomer to function as an occlusive wound dressing. To demonstrate its potential in wound dressings, a detailed comparison of commercial 3M Tegaderm(™) film and the SESi film was conducted. The SESi film exhibited similar effects in wound healing, and the wound bed was covered by the SESi film without the occurrence of significant adverse reactions.

Structural shifts of mucosa-associated lactobacilli and Clostridium leptum subgroup in patients with ulcerative colitis.

To understand the role of mucosa-associated microbiota in the pathogenicity of ulcerative colitis (UC), paired biopsies were obtained during colonoscopy from the ulcerated and nonulcerated gut mucosa of 24 patients with UC. Denaturing gradient gel electrophoresis analysis was employed to profile the composition of the dominant bacteria (16S rRNA gene V3 region) and three important groups: lactobacilli, the Clostridium leptum subgroup, and Bacteroides spp. The Pearson coefficient was used to estimate similarities between the bacterial communities of the paired biopsies for each patient. The average similarity values of bacterial composition between the paired samples were 94.8 +/- 3.8% for dominant bacteria, 59.9 +/- 26.1% for lactobacilli, 79.2 +/- 22.6% for the Clostridium leptum subgroup, and 88.7 +/- 16.4% for Bacteroides spp. The data revealed that lactobacilli and the Clostridium leptum subgroup were significantly different between the ulcerated and the nonulcerated regions. It also was noted that for lactobacilli, the composition varied significantly between biopsy sites irrespective of the location of UC in the gut but that the composition of the Clostridium leptum subgroup showed significant differences between paired samples from UC in the rectum and not in the left colon. Localized dysbiosis of the mucosa-associated intestinal microflora, especially for lactobacilli and the Clostridium leptum subgroup, may be closely related to UC.