Growth Inhibiting Effects of Four Antibiotics on Cucumber, Rape and Chinese Cabbage

Fate of emerging antibiotics in soil-plant systems: A case on fluoroquinolones

Fluoroquinolones (FQs), a class of broad-spectrum antibiotics widely used to treat human and animal diseases globally, have limited adsorption and are often excreted unchanged or as metabolites. These compounds enter the soil environment through feces, urban wastewater, or discharge of biological solids. The fluorine atoms in FQs impart high electronegativity, chemical stability, and resistance to microbial degradation, allowing them to potentially enter food chains. The persistence of FQs in soils raises questions about their impacts on plant growth, an aspect not yet conclusively determined. We reviewed whether, like other organic compounds, FQs are actively absorbed by plants, resulting in bioaccumulation and posing threats to human health. The influx of FQs has led to antibiotic resistance in soil microbes by exerting selective pressure and contributing to multidrug-resistant bacteria. Therefore, the environmental risks of FQs warrant further attention. This work provides a comprehensive review of the fate and behavior of FQs at the plant-environment interface, their migration and transport from the environment into plants, and associated toxicity. Current limitations in research are discussed and prospects for future investigations outlined. Thus, understanding antibiotic behavior in plants and translocation within tissues is not only crucial for ecosystem health (plant health), but also assessing potential human health risks. In addition, it can offer insights into the fate of emerging soil pollutants in plant-soil systems.

Metabolomic analysis reveals the impact of ketoprofen on carbon and nitrogen metabolism in rice (Oryza sativa L.) seedling leaves

Pharmacologically active compounds (PACs) are becoming common pollutants in the natural environment, posing potential risks to crop quality; however, the toxic effects and metabolic changes that they cause in agricultural plants remain unclear. Here, we investigated the effects of ketoprofen on respiration rate, ATP synthesis, carbon and nitrogen metabolism, and metabolomics in rice seedling leaves. The results showed that ketoprofen treatment adversely affected the respiration rate, ATP content, H⁺-ATPase activity and induced changes in the contents of carbon assimilation products (soluble sugar, reducing sugar, sucrose, and starch) and the activities of key enzymes in carbon metabolism (sucrose synthase (SS), sucrose phosphate synthase (SPS), and sucrose invertase (InV)). The contents of nitrate, ammonium, and free amino acids, and the activities of key enzymes involved in nitrogen metabolism (nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH)) were also affected in a concentration-dependent manner. Metabolomics analysis showed that ketoprofen disturbed the type and content of metabolites (amino acids, carbohydrates, and secondary metabolites) to varying degrees and perturbed key metabolic pathways (substance synthesis and energy metabolism), ultimately resulting in the reduction of rice seedling biomass. This study provides important information and a useful reference for the accurate assessment of the environmental risks of PACs.

The Role of Grass Compost and Zea Mays in Alleviating Toxic Effects of Tetracycline on the Soil Bacteria Community

Given their common use for disease treatment in humans, and particularly in animals, antibiotics pose an exceptionally serious threat to the soil environment. This study aimed to determine the response of soil bacteria and oxidoreductases to a tetracycline (Tc) contamination, and to establish the usability of grass compost (G) and Zea mays (Zm) in mitigating adverse Tc effects on selected microbial properties of the soil. The scope of microbiological analyses included determinations of bacteria with the conventional culture method and new-generation sequencing method (NGS). Activities of soil dehydrogenases and catalase were determined as well. Tc was found to reduce counts of organotrophic bacteria and actinobacteria in the soils as well as the activity of soil oxidoreductases. Soil fertilization with grass compost (G) and Zea mays (Zm) cultivation was found to alleviate the adverse effects of tetracycline on the mentioned group of bacteria and activity of oxidoreductases. The metagenomic analysis demonstrated that the bacteria belonging to Acidiobacteria and Proteobacteria phyla were found to prevail in the soil samples. The study results recommend soil fertilization with G and Zm cultivation as successful measures in the bioremediation of tetracycline-contaminated soils and indicate the usability of the so-called core bacteria in the bioaugmentation of such soils.

Phytotoxic Effects of Antibiotics on Terrestrial Crop Plants and Wild Plants: A Systematic Review

This review examines the state of knowledge on the phytotoxic effects of antibiotics on terrestrial crop plants and wild (non-crop) plants with the goal of evaluating differences in their sensitivity. This is important because environmental risk assessments of antibiotics currently consider their potential effects only on crop species but not wild species. Overall, we analysed 275 datasets consisting of antibiotic-plant species-endpoint combinations for germination (mg/L) and 169 datasets for plant growth (elongation and biomass) (mg/kg). EC10 and EC50 of each parameter were compared using a quotient approach, in which the geometric mean and the 5th percentile of the crop data were divided by wild data. Quotients were > 1 for elongation growth, suggesting that wild species were more sensitive than crops, while they were < 1 for biomass growth, suggesting quite the contrary. However, < 1% of the data in each dataset came from wild species, preventing definitive conclusions. Merging crop and wild data to evaluate differences in sensitivity among classes of antibiotics and plant families, we found using a linear mixed effect model and post hoc test that plants were most sensitive to phenicol and least sensitive to macrolides and tetracyclines. Further work must be conducted to gain a better understanding of the phytotoxic effects of antibiotics on terrestrial wild plants and subsequently assess whether the current approach to environmental risk assessment of antibiotics is sufficient to protect plant biodiversity.

Grafting resulting in alleviating tomato plant oxidative damage caused by high levels of ofloxacin

Antibiotic pollution has become a global problem threatening human health. Ofloxacin is one of the more widely used antibiotics, but reports on the reaction of plant to ofloxacin pollution are limited. In this study, using adversity-resistant (R), adversity-sensitive (S) and grafted plant S/R as models, we investigated the biological response of tomato to exogenous ofloxacin residues. The results showed that lower levels of ofloxacin treatment (5 mg L^-1 and 10 mg L^-1) promoted tomato growth, and 10 mg L^-1 ofloxacin was the critical dose to stimulate growth among the different treatments. In addition, the photosynthetic and fluorescence parameters, antioxidant enzyme activities and transcription-level expression of the enzymes were stimulated by low ofloxacin treatment. However, high ofloxacin treatment (20 mg L^-1 and 40 mg L^-1) exhibited a significantly negative effect on plant growth, photosynthesis, fluorescence parameters, antioxidant enzyme activities and transcript levels expression. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels increased with increasing ofloxacin concentrations, indicating that the oxidative damage of plants was severe with increasing doses. In contrast, the role of antioxidant enzymes in the antibiotic response was limited at high ofloxacin concentrations. The grafting experiment demonstrated that grafted plants had the ability to alleviate ofloxacin stress. In conclusion, ofloxacin can damage the photosynthetic machinery by promoting ROS accumulation, which results in the etiolation of tomato leaves and inhibits plant growth, but grafting can reduce its.

The tolerance mechanism and accumulation characteristics of Phragmites australis to sulfamethoxazole and ofloxacin

Antibiotic pollution has become a hot issue worldwide, which has toxic effects on plants and even threatens human health. As a common wetland plant, the tolerance mechanism of Phragmites australis to antibiotics is rarely reported. In this study, we investigated the enrichment characteristics and biological response of P. australis to sulfamethoxazole (SMZ) and ofloxacin (OFL) residues, which are common in the environment. We found that the simulated concentration of antibiotics far exceeded the current level of antibiotic residues in the water environment, but it did not significantly inhibit the growth of P. australis. At 1 mg L^-1, OFL and SMZ significantly increased the biomass of P. australis, which was mainly related to the improvement of root activity and photosynthetic efficiency, but the duplex treatment (SMZ + OFL) did not significantly stimulate the growth of reeds. OFL could significantly reduce the accumulation of reactive oxygen species (ROS) in P. australis. When OFL was 1 mg L^-1, compared with control, superoxide anion and H₂O₂ were reduced by 11.19% and 10.76%, respectively, which was mainly related to the improvement of membrane stability. SMZ and SMZ + OFL had no significant effect on ROS, but they significantly increased antioxidant enzyme activity. SMZ and OFL could increase soil invertase, urease, and protease activities, and the tested antibiotics had no significant effect on the Shannon-Wiener index of soil microorganisms. The accumulation of antibiotics within tissues could be ranked as root > leaf > stem, and the accumulation and transport of OFL were higher than those of SMZ.