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We investigated the role of the salicylic acid (SA) signaling pathway in defense responses of tomato plants to the herbivore, cotton bollworm. After exposure to the cotton bollworm, tomato leaves rapidly accumulated a high level of SA. The transcription of PR1 and BGL2 genes, the marker genes of SA pathway, was up-regulated. An enhanced endogenous SA level was accompanied by an increase in the endogenous H2O2 level as compared with controls. Spraying tomato plants with a solution containing either SA or methyl salicylic acid (Me-SA), the H2O2 level dramatically increased. These data proved that the SA pathway was involved in the tomato plant defense responses to the herbivore.

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& A high-throughput and robust method for analyzing multiclass residues of veterinary drugs in meat, milk, and egg by ultra-high performance liquid chromatography (UHPLC)-quadrupole time-of-flight mass spectrometry (QTOF) was established. The method successfully applied to the screening, quantification, and confirmation of 105 compounds from 9 different classes of drugs, including beta-agonists, benzimidazoles, corticoides, triphenylmethane, nitromidazoles, quinolones, sulfonamides, tetracylines, and benzodiazepams. The samples are extracted by a single extraction using acetonitrile containing 0.1% formic acid, followed by an easy solid phase extraction (SPE) clean-up on HLB column and finally analyzed by LC=MS QTOF MS. The separation was achieved within 30 min at the optimized chromatographic conditions. More than 92% compounds in this study can be reliably identified based on accurate mass measurement (within the 3 ppm mass error) at the 5 lg=kg concentration levels in the complex food matrix with further MS=MS confirmation. Our study demonstrated a reliable, high-efficient and high-sensitive strategy for the fast and high throughput screening of multiclass of veterinary drugs in foodstuffs of animal origin.

A method for the determination of glyphosate (PMG) and aminomethylphosphonic acid (AMPA) residues in plant products, such as rice, wheat, vegetables, fruits and tea, pig and chicken muscles, aquatic products, chestnut, honey, etc., was developed using high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS). In this method, PMG and AMPA were extracted with water from samples, defatted using an extraction step with dichloromethane, and purified using a cation-exchange (CAX) solid phase extraction cartridge. Then, these were derived using fluorenylmethylchloroformate (FMOC-Cl) in borate buffer for subsequent HPLC-MS/MS analysis. Isotope-labeled PMG 1, 2(13)- C(15) N was used as the internal standard for the quantitative analysis of two residues. For all samples, the recoveries ranged from 80.0% to 104% and the relative standard deviations (RSDs) ranged from 6.7% to 18.2%. The limit of quantification (LOQ) was determined to be 0.05 mg/kg with a linear range of 0.20-10 microg/L. It is demonstrated that this method is reliable and sensitive for the analysis of PMG and APMA with low concentrations in foods.