New structural insights into the role of TROVE2 complexes in the on-set and pathogenesis of systemic lupus erythematosus determined by a combination of QCM-D and DPI.

The mechanism of self-recognition of the autoantigen TROVE2, a common biomarker in autoimmune diseases, has been studied with a quartz crystal microbalance with dissipation monitoring (QCM-D) and dual polarization interferometry (DPI). The complementarity and remarkable analytical features of both techniques has allowed new insights into the onset of systemic lupus erythematosus (SLE) to be achieved at the molecular level. The in vitro study for SLE patients and healthy subjects suggests that anti-TROVE2 autoantibodies may undergo an antibody bipolar bridging. An epitope-paratope-specific binding initially occurs to activate a hidden Fc receptor in the TROVE2 tertiary structure. This bipolar mechanism may contribute to the pathogenic accumulation of anti-TROVE2 autoantibody immune complex in autoimmune disease. Furthermore, the specific calcium-dependent protein-protein bridges point out at how the TRIM21/TROVE2 association might occur, suggesting that the TROVE2 protein could stimulate the intracellular immune signaling via the TRIM21 PRY-SPRY domain. These findings may help to better understand the origins of the specificity and affinity of TROVE2 interactions, which might play a key role in the SLE pathogenesis. This manuscript gives one of the first practical applications of two novel functions (-df/dD and Δh/molec) for the analysis of the data provided by QCM-D and DPI. In addition, it is the first time that QCM-D has been used for mapping hidden Fc receptors as well as linear epitopes in a protein tertiary structure. Graphical abstract ᅟ.

Development of a Photoinduced Chemiluminescent Method for the Determination of the Herbicide Quinmerac in Water.

A new, simple, and sensitive method, based on photoinduced chemiluminescence, was developed for the determination of quinmerac. The photoproduct, obtained after ultraviolet irradiation in basic medium, was mixed with sodium sulfite (sensitizer), and Ce(IV) (oxidant) in acid medium. A wide linear dynamic range (2-600 ng mL(-1)) and a limit of detection of 0.6 ng mL(-1) were obtained without any pretreatment (0.08 ng mL(-1) after solid-phase extraction). The determination was performed using a flow-injection manifold, which allowed a high throughput (144 h(-1)). The interday reproducibility was 5.6% (n = 5), and the intraday repeatability was 3.9 and 2.9% for 20 and 200 ng mL(-1) of quinmerac, respectively (n = 21). Finally, the method was applied to surface water and groundwater, with recoveries ranging from 78.1 to 94.5%.

Fast determination of thiacloprid by photoinduced chemiluminescence.

A new and sensitive application of chemiluminescence detection has been developed for the determination of the pesticide thiacloprid in water. It was based on the on-line photoreaction of thiacloprid in a basic medium, with quinine acting as the sensitizer of the chemiluminescent response; cerium (IV) in sulfuric acid medium was used as the oxidant. High degrees of automation and reproducibility were achieved using a flow-injection analysis (FIA) manifold. The validation of the method was performed in terms of selectivity, linearity, limit of detection (LOD), precision, and accuracy. Liquid chromatography with ultraviolet (UV) detection was used as reference for mineral, tap, ground, and spring water samples. The proposed method is fast (with a throughput of 130 h(-1)), sensitive (LOD of 0.8 ng mL(-1) without preconcentration steps and of 0.08 ng mL(-1) with solid-phase extraction [SPE]), low cost, and possible to couple with separation methods for the simultaneous determination of other pesticides. The enhanced chemiluminescence intensity was linear with the thiacloprid concentration above the 2-80 and 80-800 ng mL(-1) ranges. A possible reaction mechanism is also discussed.

FI-photoinduced chemiluminescence method for diuron determination in water samples.

A new method for the determination of the herbicide diuron, using a flow injection manifold and photoinduced chemiluminescence detection, is presented. The pesticide, in basic medium, was irradiated on-line with UV light (254 nm) for 53 s. A short discussion about the possible irradiation products is included. The chemiluminescent response of the photoproducts was induced by oxidation with potassium ferricyanide in phosphate buffer at pH 11.5. The method permitted the quantification of diuron over the 0.1-4.0 mg L(-1) range, with a detection limit (S/N = 3) of 20 µg L(-1) when the method was applied directly. However, the use of solid phase extraction (SPE) performed with C(18) cartridges allowed us to achieve a limit of detection of 0.4 µg L(-1) and a 1.5-30 µg L(-1) dynamic range. The method was successfully applied to the diuron determination in samples of water from different sources (spring, ground, mineral, irrigation, sea and tap waters) with a low consumption of reagents.