Determination of oxolinic acid residues in the muscle tissue of olive flounder (Paralichthysolivaceus) by a lateral flow immunoassay

In-feed oxolinic acid induces oxidative stress and histopathological alterations in Nile tilapia Oreochromis niloticus

The aquaculture industry urgently requires effective bacterial disease management strategies, necessitating better regulation of antibiotic application. This study investigated the effects of oral oxolinic acid (OA) administration on Oreochromis niloticus at the recommended dose of 12 mg (1 ×) and overdose of 36 mg (3 ×)/kg biomass/day for 7 consecutive days in terms of growth, oxidative stress, residue accretion and histopathology relative to the control. The 1 × and 3 × groups experienced dose-dependent mortalities (3.33-8.33 %). The OA residues peaked in the liver and kidney tissues with dosing and declined upon discontinuation. The residues persisted in the kidney even on day 35 post-dosing. Elevated malondialdehyde and total nitric oxide levels signified oxidative stress and correlated with the tissue level changes in various organs. Histologically, glycogen-type vacuolation and cellular hypertrophy were observed in the liver. The kidney had hydropic swelling, renal epithelium degradation, nephrocalcinosis, vacuolation, and necrosis. Splenic alterations were confined to necrosis and a slight increase in sinusoidal space. Intestinal tissues exhibited a depletion of absorptive vacuoles, epithelial layer degradation, mucinous degeneration, and necrosis. Gills displayed epithelial hyperplasia, thickening of secondary lamellae, and erosion. Nevertheless, the cohort administered the recommended dose exhibited recovery with OA discontinuation. However, none of the assessed parameters normalized in the overdosed group even after 35 days of dose suspension. The results indicated that O. niloticus can safely adapt to and tolerate the toxic effects of OA. As the recommended dose of OA elicited reversible bioresponses effectively in tilapia, it can be utilized in aquaculture with due caution following regulations.

Oxolinic Acid Generated Green Fluorescence Based on a Terbium-Functionalized Covalent Organic Framework

Oxolinic acid (OXO), a classic environmental contaminant, has a terrible detrimental effect on human health. The exploration of efficient strategies to detect and detecting OXO has remarkable significance. Herein, we reported a novel terbium(III)-functionalized covalent organic framework (Bpy-DhBt-COF@Tb3+) by fixing Tb3+ on the bipyridine-connecting COF (Bpy-DhBt-COF) as a turn-on fluorescent switch toward OXO for the first time. In this platform, Tb3+ acts as the specific recognition units for OXO and the response signal, while Bpy-DhBt-COF acts as the safehaven for Tb3+. Once introducing OXO to Bpy-DhBt-COF@Tb3+, OXO can instead water molecules coordinate with Tb3+ and sensitize Tb3+ instantly, thereby producing a significant fluorescence signal. Profiting from the excellent porosity of Bpy-DhBt-COF@Tb3+, it can obtain optimal response toward OXO only within 10 s with an ultrasensitive detection limit of 12.5 nM. Furthermore, Bpy-DhBt-COF@Tb3+ displayed outstanding selectivity toward OXO than other general quinolones. Based on these, a Tb3+-based COF was explored for the first time for the turn-on fluorescence detection of an OXO with rapid response, high sensitivity, and outstanding selectivity. In this work, we not only exhibit the attractive performance of Tb3+-functionalized COF to detect OXO but also propose a prospect strategy for creating other fluorescent sensors for multiple targets.

Cost-effective one-spot hydrothermal synthesis of graphene oxide nanoparticles for wastewater remediation: AI-enhanced approach for transition metal oxides

This investigation presents a cost-efficient hydrothermal synthesis technique for producing graphene oxide nanoparticles (GO-NPs) that exhibit promising potential in wastewater treatment. The synthesis process involves a facile and expandable hydrothermal reactor that can be regulated using an AI-empowered methodology. The generated GO-NPs were characterised using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, and transmission electron microscopy (TEM), confirming their successful synthesis and high quality. The high degree of crystallinity observed in the GO-NPs can be attributed to the favourable reaction conditions facilitated by the hydrothermal synthesis. The TEM analysis showed that the GO-NPs had a homogeneous dispersion pattern and a consistent size distribution of approximately 10 nm. Carboxylation was employed to functionalize the GO-NPs, enhancing their reactivity towards diverse contaminants present in wastewater. The remediation potential of the GO-NPs for transition metal oxides, which are frequently found in wastewater, was assessed. The GO-NPs exhibited notable efficacy in remediating the transition metal oxides that were subjected to testing. The heightened efficacy of remediation can be attributed to the substantial surface area and elevated reactivity of the GO-NPs, in addition to their functionalization using carboxylic groups. The cost-effective and efficient synthesis method, coupled with the high remediation potential of the GO-NPs, makes them a highly promising contender for employment in wastewater remediation applications. The use of AI in regulating the hydrothermal synthesis procedure enables accurate manipulation of the reaction parameters, thereby augmenting the quality and uniformity of the resultant GO-NPs. The proposed method exhibits scalability potential for large-scale production of GO-NPs, presenting a viable remedy for the challenges associated with wastewater remediation.

Effect of pH on Adsorption of Tetracycline Antibiotics on Graphene Oxide

Graphene oxide (GO) has good dispersibility and adsorption capacity for antibiotics adsorption, a complex process influenced by many factors. In this work, the adsorption mechanism of GO on tetracycline antibiotics at different pH was studied to address its attenuated effects on the microbial growth. The results showed that the adsorption process of GO on three antibiotics, namely, tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC), followed the pseudo-second-order kinetic model. The maximum adsorption capacities were observed at pH5 which were 133.0 mg/g for TC, 125.4 mg/g for OTC, and 167.0 mg/g for CTC. Furthermore, the reaction was uniform adsorption with a single layer on the surface of GO, and heating was conducive to the reaction. In the microbial growth experiment, the growth of E. coli and B. subtilis senses was optimal at pH5, which was consistent with the adsorption experiment. This study analyzed the effect of pH on the adsorption of antibiotics by GO and provided a theoretical basis for the further application of GO in various aquatic environments.