Synthesis and In Vitro and In Vivo Biological Activity Evaluation and Quantitative Proteome Profiling of Oxadiazoles Bearing Flexible Heterocyclic Patterns

Abstract

A novel series of simple 1,3,4-oxadiazoles that bear flexible heterocyclic patterns was prepared, and their biological activities in plant pathogenic bacteria, fungi, oomycetes, and Meloidogyne incognita in vitro and in vivo were screened to explore low-cost and versatile antimicrobial agents. Screening results showed that compounds, such as A 0 , B 0 , and C 4 , were bioactive against Xanthomonas oryzae pv oryzae in vitro and in vivo, and such bioactivities were superior to those of commercial agents bismerthiazol and thiodiazole copper. Their antibacterial mechanisms were further investigated by quantitative proteomics and concentration-dependent scanning electron microscopy images. Antifungal results indicated that compound A 0 displayed a selective and better antifungal effect on Botrytis cinerea with inhibition rate of 96.8% at 50 μg/mL. Nematocidal bioassays suggested that compound D 1 had good in vitro nematocidal activity toward M. incognita at 24, 48, and 72 h, with the corresponding insecticidal efficiency of 48.7%, 64.1%, and 87.2% at 40 μg/mL. In vivo study further confirmed that compounds D 1 and F 2 showed nematocidal actions at 80 μg/mL with a disease index of 1.5. Given these advantages, this kind of molecular frameworks could be a suitable platform for exploring highly efficient agrochemicals.

Synthesis and Antibacterial Evaluation of Novel 1,3,4-Oxadiazole Derivatives Containing Sulfonate/Carboxylate Moiety

“…Fluorine nuclear magnetic resonance ( 19 F NMR) was involved for some fluoride structures. In addition, we reported the splicing of oxymethyl and 1,3,4-oxadiazole sulfone derivatives could provide excellent antibacterial activity [10,30]. Based on those prior works, we hypothesized that sulfonate/carboxylate moiety functionalized 1,3,4-oxadiazole derivatives might also show promising antibacterial activity.…”

“…Scanning electron microscopy offers the ability to observe the bacterial cell surface [30]. Based on the analysis of antibacterial against Xoo results in vitro and in vivo, the antibacterial mechanism of compound 4a-2 was studied by SEM.…”

“…The sample preparation method was as follows [30]. A certain quantity of microcentrifuge tube (2 ml) was prepared and added bacteria solution of Xoo (1.5 mL).…”

“…Compounds 4a-1, 4a-2 and 4a-3 were tested for the protective and curative activity in vivo against rice bacterial leaf blight by leaf-cutting method [10,30] at 200 µg/mL, with comparing to bismerthiazol and thiodiazole copper. A negative control check (CK) was set up identically with absence of the test compound.…”

Transcriptome Analysis on the Mechanism of Ethylicin Inhibiting Pseudomonas syringae pv. actinidiae on Kiwifruit

“…The sample preparation procedure for scanning electron microscopy followed the reported method [27]. The 1.5 mL of Psa bacterial solution with OD 600 = 0.6-0.8 was taken in 2 mL tubes and centrifuged, and the precipitate was washed three times with phosphate buffer solution (PBS) (pH = 7.2) and resuspended in 1.5 mL of PBS.…”