Shuliang Liu

Given the potential hazards of enrofloxacin (ENR) residues to human health, establishing an accurate, rapid, and stable detection method is of importance. To enable the direct detection of ENR, an electrochemical sensor was constructed in this study. N- and S-doped carbon quantum dots (CQDs) with peroxidase-like activity were prepared using DL-malic acid, L-alanine, and L-cysteine as precursors and compounded with a tetrakis (4-carboxyphenyl) porphyrin (TCPP) and Fe(NO₃)₃·9H₂O to make novel N/S CQDs@Fe-TCPP composite carbon-based nanozymes to construct an electrochemical sensor, and the electrochemical behavior was investigated. Under optimal experimental conditions, the sensor exhibited a linear current response to ENR concentrations in the range of 1–1300 nM (I (μA) = 0.0106c (nM) + 2.9861, R² = 0.9962), with a calculated detection limit of 0.872 nM (S/N = 3). The recovery rate of this sensor in actual milk samples ranged from 99.02% to 100.9%. The reproducibility experiments demonstrated the high precision of the method, with a relative standard deviation (RSD) of 1.27%. Stability testing revealed a peak current retention rate of 93.51% on day 21, indicating excellent system stability. These findings indicate that the sensor shows great capability for ENR detection in food products.

Phenolic acid decarboxylase (PAD) is an enzyme capable of catalyzing the nonoxidative decarboxylation of phenolic acids, yielding the corresponding 4-vinyl

Pyrethroid residues in the environment and agricultural products have caused significant negative effects on food safety and human health. In this study, a novel strain of Bacillus subtilis J6, isolated from the cecum of broilers, exhibited the ability to degrade cypermethrin and its major metabolite, 3-phenoxybenzoic acid. The identified intermediates indicated that B. subtilis J6 degrades cypermethrin through ester bond hydrolysis, benzene hydroxylation, and ether bond cleavage. Predictive toxicology analysis suggested that this degradation process effectively reduces toxicity. Transcriptomic analysis revealed that esterases, oxidoreductases, cytochrome P450 enzymes, and ring-cleavage dioxygenases may contribute to cypermethrin degradation. In addition, B. subtilis J6 mitigates cypermethrin stress by enhancing growth metabolism, sporulation, and material transport, whereas it downregulates pathways associated with cell motility and respiration. These findings identify B. subtilis J6 as a promising candidate for pyrethroid bioremediation in the food and feed industries and provide new insights into its degradation pathways and adaptive responses.