New extraction method prior to screening of organic micropollutants in various biota matrices using liquid chromatography coupled to high-resolution time-of-flight mass spectrometry.

A new extraction method with limited clean-up requirements prior to screening various matrices for organic micropollutants using liquid chromatography-high resolution mass spectrometry (LC-HRMS) for analysis was developed. First, the performance of three extraction methods (QuEChERS with SPE clean-up, ultrasonication with SPE clean-up, extraction without SPE clean-up) was tested, optimized, and compared using >200 contaminants of emerging concern (CECs) together covering a wide range of physicochemical properties applicable for suspect and non-target screening in biota. White-tailed sea eagle (Haliaeetus albicilla) muscle tissue was used in method development and optimization. The method without SPE clean-up was then applied to European perch (Perca fluviatilis) muscle, heart, and liver tissues. The optimization and application of the method demonstrated a wide applicable domain of the novel extraction method regarding species, tissues, and chemicals. For future applications, the suitability of the method for suspect and non-target screening was tested. Overall, our extraction method appears to be sufficiently simple and broad (relatively non-discriminant) for use prior to analysis of CECs in various biota.

Arabidopsis 14-3-3 epsilon members contribute to polarity of PIN auxin carrier and auxin transport-related development.

Eukaryotic 14-3-3 proteins have been implicated in the regulation of diverse biological processes by phosphorylation-dependent protein-protein interactions. The Arabidopsis genome encodes two groups of 14-3-3s, one of which - epsilon - is thought to fulfill conserved cellular functions. Here, we assessed the in vivo role of the ancestral 14-3-3 epsilon group members. Their simultaneous and conditional repression by RNA interference and artificial microRNA in seedlings led to altered distribution patterns of the phytohormone auxin and associated auxin transport-related phenotypes, such as agravitropic growth. Moreover, 14-3-3 epsilon members were required for pronounced polar distribution of PIN-FORMED auxin efflux carriers within the plasma membrane. Defects in defined post-Golgi trafficking processes proved causal for this phenotype and might be due to lack of direct 14-3-3 interactions with factors crucial for membrane trafficking. Taken together, our data demonstrate a fundamental role for the ancient 14-3-3 epsilon group members in regulating PIN polarity and plant development.