T.C. Istanbul Aydin University, Health Services Vocational School of Higher Education, Sefakoy Kucukcekmece, 34295 Istanbul, Turkey.
T.C. Istanbul Aydin University, Health Services Vocational School of Higher Education, Sefakoy Kucukcekmece, 34295 Istanbul, Turkey.
Sci Total Environ. 2020 Feb 10;703:135024. doi: 10.1016/j.scitotenv.2019.135024. Epub 2019 Nov 3.
Microplastics have become a global concern due to their increasing use and discharge into the environment. These ubiquitous particles are known to have extremely low degradation rates and accumulate mostly in the marine environment. The evidence for bioaccumulation and indicators of stress linked to microplastics is also stated in the literature. However, the real environmental impact of microplastics has not yet been revealed. Therefore, it is crucial to understand the interaction mechanisms between microplastics and (micro)organisms under controlled (standard) laboratory conditions and environmentally relevant conditions to reflect the true environmental -situation. In this study, we aimed to understand how microplastics extracted from commercially available toothpaste samples interacted with four types of bacteria under both standard and seawater conditions. For this purpose, bacterial inhibitions were examined, and mechanisms of inhibition were evaluated by biochemical parameters (total protein, lipid peroxidase, total antioxidant capacity, and extracellular carbohydrate levels) of bacteria and physicochemical properties (zeta potential, particle size, surface chemistry) of microplastics. Results showed that gram-positive Bacillus subtilis and gram-negative Pseudomonas aeruginosa were affected in controlled and sea water media, respectively. The inhibition of the bacteria relied on the high zeta potentials of the microplastics, and, biochemically, protein and lipid peroxidase activity of bacteria were important in both media. On the other hand, while biochemical responses were similar in both media, the difference between the cell wall and microplastics surface charge was important only in seawater.
由于微塑料的广泛使用及其向环境中的排放，微塑料已成为全球性关注的问题。这些普遍存在的颗粒已知具有极低的降解率，并且主要在海洋环境中积累。文献中也提到了与微塑料有关的生物累积和应激指标。然而，微塑料的真正环境影响尚未揭示。因此，了解在受控（标准）实验室条件和环境相关条件下微塑料与（微生物）之间的相互作用机制，以反映真实的环境情况至关重要。在这项研究中，我们旨在了解从市售牙膏样品中提取的微塑料如何在标准和海水条件下与四种细菌相互作用。为此，我们检查了细菌的抑制作用，并通过细菌的生化参数（总蛋白、脂质过氧化物酶、总抗氧化能力和细胞外碳水化合物水平）和微塑料的物理化学性质（zeta 电位、粒径、表面化学）来评估抑制机制。结果表明，革兰氏阳性枯草芽孢杆菌和革兰氏阴性铜绿假单胞菌分别在控制和海水介质中受到影响。细菌的抑制作用依赖于微塑料的高 zeta 电位，并且在两种介质中，细菌的蛋白质和脂质过氧化物酶活性都很重要。另一方面，虽然两种介质中的生化反应相似，但细胞壁和微塑料表面电荷之间的差异在海水中很重要。
