Abstract：
The presence and accumulation of both, plastics and antibiotics in soils may lead to the colonization, selection, and propagation of soil bacteria with certain metabolic traits, e.g., antibiotic resistance, in the plastisphere. However, the impact of plastic-antibiotic tandem on the soil ecosystem functioning, particularly on microbial function and metabolism remains currently unexplored. Herein, we investigated the competence of soil bacteria to colonize plastics and degrade 13C-labeled sulfamethoxazole (SMX). Using single-cell imaging, isotope tracers, soil respiration and SMX mineralization bulk measurements we show that microbial colonization of polyethylene (PE) and polystyrene (PS) surfaces takes place within the first 30 days of incubation. Morphologically diverse microorganisms were colonizing both plastic types, with a slight preference for PE substrate. CARD-FISH bacterial cell counts on PE and PS surfaces formed under SMX amendment ranged from 5.36 × 103 to 2.06 × 104, and 2.06 × 103 to 3.43 × 103 hybridized cells mm-2, respectively. Nano-scale Secondary Ion Mass Spectrometry measurements show that 13C enrichment was highest at 130 days with values up to 1.29 atom%, similar to those of the 13CO2 pool (up to 1.26 atom%, or 22.55 ‰). Independent Mann-Whitney U test showed a significant difference between the control plastisphere samples incubated without SMX and those in 13C-SMX incubations (P < 0.001). Our results provide direct evidence demonstrating, at single-cell level, the capacity of bacterial colonizers of plastics to assimilate 13C-SMX from contaminated soils. These findings expand our knowledge on the role of soil-seeded plastisphere microbiota in the ecological functioning of soils impacted by anthropogenic stressors.
摘要：
两者的存在和积累，土壤中的塑料和抗生素可能导致定植，选择,以及具有某些代谢特性的土壤细菌的繁殖，例如，抗生素耐药性,在质体中。然而,塑料-抗生素串联对土壤生态系统功能的影响，特别是在微生物功能和代谢方面，目前仍未探索。在这里，我们研究了土壤细菌定植塑料和降解13C标记的磺胺甲恶唑（SMX）的能力。使用单细胞成像，同位素示踪剂,土壤呼吸和SMX矿化批量测量表明，聚乙烯（PE）和聚苯乙烯（PS）表面的微生物定植发生在孵育的前30天内。形态多样的微生物定植于两种塑料类型，轻微偏好PE基材。在SMX修饰下形成的PE和PS表面上的CARD-FISH细菌细胞计数范围分别为5.36×103至2.06×104和2.06×103至3.43×103杂交细胞mm-2。纳米级二次离子质谱测量表明，13C富集在130天时最高，值为1.29原子％，与13CO2池相似(高达1.26原子%，或22.55‰)。独立的Mann-WhitneyU检验显示了在没有SMX的情况下孵育的对照质体样品与在13C-SMX孵育中的对照质体样品之间的显著差异(P<0.001)。我们的结果提供了直接的证据证明，在单细胞水平，塑料的细菌定植剂从污染土壤中吸收13C-SMX的能力。这些发现扩展了我们对土壤播种的质体微生物群在受人为胁迫影响的土壤生态功能中的作用的认识。
