Improving the efficacy against crop foliage disease by regulating fungicide adhesion on leaves with soft microcapsules.

BACKGROUND: Increasing pesticide retention on crop leaves is a key approach for guaranteeing efficacy when products are applied to foliage. Evidently, the formulation plays an important role in this process. Microcapsules (MCs) are a promising formulation, but whether and how their adhesion to the leaf surface affects retention and efficacy is not well understood. RESULTS: In this study, we found that the incorporation of polyethylene glycol (PEG) with different molecular weights into the MC shell affects the release profile of MCs and the contact area of these MCs to leaves by changing their softness. The cumulative release rates of pyraclostrobin (Pyr) MCs fabricated with PEG200, PEG400, PEG800 and PEG1500 were 80.61%, 90.98%, 94.07% and 97.40%, respectively. Scanning electron microscopy observations showed that the flexibility of the MCs increased with increasing PEG molecular weight. The median lethal concentration (LC50 ) of the MCs with different PEG to the zebrafish were 12.10, 8.10, 3.90 and 1.46 mg L-1 , respectively, which also indirectly reflected their release rate. Rainwater had less influence on the retention of the MCs prepared with PEG1500 than with the other PEG, which indicates a better adhesion to the target leave surfaces. MCs with the highest residual efficacy had better control efficacy on peanut leaf spot in field trials. CONCLUSION: Overall, adding PEG with an appropriate molecular weight to the MC shell can regulate the structure of the MC shell to improve the affinity between the MCs and leaves, which further improves the utilization of pesticides and reduces the environmental risks of pesticides. © 2021 Society of Chemical Industry.

Promoter methylation of RNF180 is associated with H.pylori infection and serves as a marker for gastric cancer and atrophic gastritis.

Promoter methylation (PM) of RING-finger protein (RNF) 180 affects gastric cancer (GC) prognosis, but its association with risk of GC or atrophic gastritis (AG) is unclear. We investigated relationships between RNF180 PM and GC or AG, and the effects of Helicobactor pylori (H.pylori) infection on RNF180 PM. This study included 513 subjects (159 with GC, 186 with AG, and 168 healthy controls [CON]) for RNF180 PM analysis, and another 55 GC patients for RNF180 gene expression analysis. Methylation was quantified using average methylation rates (AMR), methylated CpG site counts (MSC) and hypermethylated CpG site counts (HSC). RNF180 promoter AMR and MSC increased with disease severity. Optimal cut-offs were GC + AG: AMR > 0.153, MSC > 4 or HSC > 1; GC: AMR > 0.316, MSC > 15 and HSC > 6. Hypermethylation at 5 CpG sites differed significantly between GC/AG and CON groups, and was more common in GC patients than AG and CON groups for 2 other CpG sites. The expression of RNF180 mRNA levels in tumor were significantly lower than those in non-tumor, with the same as in hypermethylation than hypomethylation group. H.pylori infection increased methylation in normal tissue or mild gastritis, and increased hypermethylation risk at 3 CpG sites in AG. In conclusion, higher AMR, MSC and HSC levels could identify AG + GC or GC. Some RNF180 promoter CpG sites could identify precancerous or early-stage GC. H.pylori affects RNF180 PM in normal tissue or mild gastritis, and increases hypermethylation in 3 CpG sites in AG.