Enzymatic Profile of 'Willamette' Raspberry Leaf and Fruit Affected by Prohexadione-Ca and Young Canes Removal Treatments

Assessment of Environmental Pollution and Human Exposure to Pesticides by Wastewater Analysis in a Seven-Year Study in Athens, Greece

Pesticides have been used in large amounts around the world for decades and are responsible for environmental pollution and various adverse effects on human health. Analysis of untreated wastewater can deliver useful information on pesticides’ use in a particular area and allow the assessment of human exposure to certain substances. A wide-scope screening method, based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry, was applied, using both target and suspect screening methodologies. Daily composite influent wastewater samples were collected for seven or eight consecutive days in Athens between 2014 and 2020 and analyzed for 756 pesticides, their environmental transformation products and their human metabolites. Forty pesticides were quantified at mean concentrations up to 4.9 µg/L (tralkoxydim). The most abundant class was fungicides followed by herbicides, insect repellents, insecticides and plant growth regulators. In addition, pesticide transformation products and/or metabolites were detected with high frequency, indicating that research should be focused on them. Human exposure was evaluated using the wastewater-based epidemiology (WBE) approach and 3-ethyl-carbamoyl benzoic acid and cis-1,2,3,6-tetrahydrophthalimide were proposed as potential WBE biomarkers. Wastewater analysis revealed the presence of unapproved pesticides and indicated that there is an urgent need to include more transformation products in target databases.

Improved synthetic route of exo-16,17-dihydro-gibberellin A5-13-acetate and the bioactivity of its derivatives towards Arabidopsis thaliana

BACKGROUND

The use of exo-16,17-dihydro-gibberellin A5-13-acetate (DHGA₅ ) in agriculture has been limited by its low synthetic yield. This study was aimed at optimizing the synthetic route of DHGA₅ , designing and synthesizing new derivatives with strong plant growth inhibitory activities.

RESULTS

Previous synthetic methods were replaced with a shorter, milder and faster reaction route with higher yield (76.3%) of DHGA₅ . Based on this novel route, a series of new derivatives were designed and synthesized using DHGA₅ as a lead compound and characterized and evaluated for biological activities in Arabidopsis thaliana. Among the 15 tested derivatives, compound 14j showed a lower medium inhibition concentration (IC₅₀ , 73 μm) in Arabidopsis than that of DHGA₅ (91 μm). Gibberellin deficient mutant assay further revealed that 14j had very different activities compared to DHGA₅ as it specifically inhibits gibberellin biosynthetic pathways. In addition, 14j does not influence the interaction between gibberellin receptors (GID1) and the master growth repressor (RGA) based on yeast two-hybrid assay.

CONCLUSION

The optimized synthetic route provides a promising method for large-scale preparation of DHGA₅ . Our biological assays indicate that 14j likely acts on gibberellin signaling elements other than GID1. These results indicate that novel plant growth regulators can be developed. © 2019 Society of Chemical Industry.