Multiresidue Screening of Veterinary Drugs in Meat, Milk, Egg, and Fish Using Liquid Chromatography Coupled with Ion Trap Time-of-Flight Mass Spectrometry.

New approaches to veterinary drug screening based on liquid chromatography-mass spectrometry (LC-MS/MS) and time-of-flight mass spectrometry (ToF/MS) are rapid and have high selectivity and sensitivity. In this study, we developed a multiresidue method for screening over 100 veterinary drug residues using ion trap (IT)-ToF/MS. The screened compounds comprised major drug classes used in veterinary practice, representing the following: amphenicols, anthelmintics, benzimidazoles, β-lactams, coccidiostats, ionophores, macrolides, non-steroidal anti-inflammatory drugs, quinolones, sulfonamides, tetracyclines, and tranquilizers.

Magnetic nanoparticle based purification and enzyme-linked immunosorbent assay using monoclonal antibody against enrofloxacin.

Monoclonal anti-enrofloxacin antibody was prepared for a direct competitive enzyme-linked immunosorbent assay (ELISA) and purification system using monoclonal antibody (mAb) coupled magnetic nanoparticles (MNPs). The IC50 values of the developed mAb for enrofloxacin (ENR), ciprofloxacin, difloxacin, sarafloxacin, pefloxacin, and norfloxacin were 5.0, 8.

Veterinary drug residues in domestic and imported foods of animal origin in the Republic of Korea.

The Korean National Residue Programme comprises three different approaches for evaluating domestic and imported foods of animal origin: monitoring, surveillance/enforcement and an exploratory test programme. Monitoring and surveillance/enforcement testing programmes are routinely implemented by 17 Provincial Veterinary Services for domestic products and regional offices of the Animal and Plant Quarantine Agency (QIA) for imported products. The exploratory project conducted at QIA headquarters is designed to test substances that are not included in monitoring and enforcement testing programmes.

Chemical residues and contaminants in foods of animal origin in Korea during the past decade.

Residues of veterinary drugs, pesticides, and environmental contaminants in domestic and imported foods of animal origin were monitored by the National Residue Program and inspection service in Korea in the past decade. In all, 134 substances were analyzed in the monitoring plan; 35 substances were examined in the surveillance and enforcement testing program, and 27 substances were investigated in exploratory projects. The overall trend of violation rates gradually decreased over the past decade.

Overexpression of salicylic acid carboxyl methyltransferase reduces salicylic acid-mediated pathogen resistance in Arabidopsis thaliana.

We cloned a salicylic acid/benzoic acid carboxyl methyltransferase gene, OsBSMT1, from Oryza sativa. A recombinant OsBSMT1 protein obtained by expressing the gene in Escherichia coli exhibited carboxyl methyltransferase activity in reactions with salicylic acid (SA), benzoic acid (BA), and de-S-methyl benzo(1,2,3)thiadiazole-7-carbothioic acid (dSM-BTH), producing methyl salicylate (MeSA), methyl benzoate (MeBA), and methyl dSM-BTH (MeBTH), respectively. Compared to wild-type plants, transgenic Arabidopsis overexpressing OsBSMT1 accumulated considerably higher levels of MeSA and MeBA, some of which were vaporized into the environment.

Microarray-based screening of jasmonate-responsive genes in Arabidopsis thaliana.

Jasmonates comprise a family of plant hormones that regulate gene expression to modulate diverse developmental and defensive processes. To screen a set of jasmonate-responsive Arabidopsis genes, we performed a microarray analysis using an Affymetrix GeneChip containing about 8,300 gene probes synthesized in situ. External treatment with 100 microM methyl jasmonate resulted in significant changes (more than twofold increases or decreases) in the expression levels of 137 genes in the rosette leaves of 5-week-old Arabidopsis plants.