Nunes Bruno, Veiga Vítor, Frankenbach Silja, Serôdio João, Pinto Glória
Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal; Centro de Estudos do Ambiente e do Mar, Laboratório Associado (CESAM, LA) Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal.
Environ Toxicol Pharmacol. 2019 Nov;72:103242. doi: 10.1016/j.etap.2019.103242. Epub 2019 Aug 14.
The worldwide increase in the consumption of antibiotics is becoming a concern for the scientific community, since the presence of their residues in the wild poses specific challenges, especially in ecotoxicological terms. Currently, antibiotics are used for a wide range of purposes, being used against bacterial diseases but also as growth promoters. As a result, their environmental presence can affect wild organisms, especially those from the aquatic environment. This scenario leads to the need of characterizing the toxicity of antibiotics, especially towards non-target organisms. In this study we selected two species of aquatic macrophytes, Lemna minor and Lemna gibba, which are standard plant species inscribed in ecotoxicological testing guidelines. In this work we characterized the toxic effects of the quinolone antibiotic ciprofloxacin (in levels of 0.005, 0.013, 0.031, 0.078, and 0.195 mg/L), focusing on its potential toxicity towards photosynthetic mechanisms, and pro-oxidant effects. These objectives were attained by measuring the concentrations of chlorophyll a and b, and carotenoids levels. The determination of the quantum yield allowed assessing the effects of ciprofloxacin on the photochemical efficiency of the Photosystem II (PSII). The pro-oxidant effects induced by ciprofloxacin were evaluated by measuring oxidative stress biomarkers, such as catalase activity, and also by determining lipoperoxidation levels. The obtained results showed no differences in terms of the content of both chlorophylls a and b, or any change in the photochemical efficiency of the PSII; however, the global carotenoids content of L. gibba were significantly decreased. The activity of the anti-oxidant enzyme catalase was also significantly increased in L. minor. L. gibba showed a decrease in lipid peroxidation levels, but only for the two lowest concentrations of ciprofloxacin. The global set of data shows the activation of the anti-oxidant defensive system of both plant species, a response that was likely activated by the pro-oxidant character of ciprofloxacin. Our data demonstrate the interference of this therapeutic compound at different levels of plant metabolism, at ecologically relevant concentrations. In fact, the obtained results are of ecological relevance since they illustrate deleterious effects that may compromise the physiology of aquatic non-target plant species.
全球抗生素消费量的增加正引起科学界的关注，因为其在野外残留的存在带来了特定挑战，尤其是在生态毒理学方面。目前，抗生素有广泛的用途，既用于对抗细菌性疾病，也用作生长促进剂。因此，它们在环境中的存在会影响野生生物，尤其是来自水生环境的生物。这种情况导致需要对抗生素的毒性进行表征，特别是对非靶标生物的毒性。在本研究中，我们选择了两种水生大型植物，浮萍（Lemna minor）和紫萍（Lemna gibba），它们是生态毒理学测试指南中规定的标准植物物种。在这项工作中，我们表征了喹诺酮类抗生素环丙沙星（浓度为0.005、0.013、0.031、0.078和0.195 mg/L）的毒性作用，重点关注其对光合机制的潜在毒性和促氧化作用。这些目标是通过测量叶绿素a和b以及类胡萝卜素水平的浓度来实现的。量子产率的测定允许评估环丙沙星对光系统II（PSII）光化学效率的影响。通过测量氧化应激生物标志物（如过氧化氢酶活性）以及测定脂质过氧化水平来评估环丙沙星诱导的促氧化作用。获得的结果表明，叶绿素a和b的含量没有差异，PSII的光化学效率也没有任何变化；然而，紫萍的总类胡萝卜素含量显著降低。浮萍中的抗氧化酶过氧化氢酶活性也显著增加。紫萍的脂质过氧化水平降低，但仅针对环丙沙星的两个最低浓度。总体数据集显示了两种植物物种抗氧化防御系统的激活，这种反应可能是由环丙沙星的促氧化特性激活的。我们的数据证明了这种治疗化合物在生态相关浓度下对植物代谢不同水平的干扰。事实上，获得的结果具有生态相关性，因为它们说明了可能损害水生非靶标植物物种生理的有害影响。
