Kohlmeier Stefanie, Smits Theo H M, Ford Roseanne M, Keel Christoph, Harms Hauke, Wick Lukas Y
Swiss Federal Institute of Technology Lausanne (EPFL), ENAC-ISTE-LPE, CH-1015 Lausanne, Switzerland.
Environ Sci Technol. 2005 Jun 15;39(12):4640-6. doi: 10.1021/es047979z.
The capacity of fungi to serve as vectors for the dispersion of pollutant-degrading bacteria was analyzed in laboratory model systems mimicking water-saturated (agar surfaces) and unsaturated soil environments (glass-bead-filled columns). Two common soil fungi (Fusarium oxysporum and Rhexocercosporidium sp.) forming hydrophilic and hydrophobic mycelia, respectively, and three polycyclic aromatic hydrocarbon degrading bacteria (Achromobacter sp. SK1, Mycobacterium frederiksbergense LB501TG, and Sphingomonas sp. L138) were selected based on the absence of mutual antagonistic effects. It was shown that fungal hyphae act as vectors for bacterial transport with mobilization strongly depending on the specific microorganisms chosen: The motile strain Achromobacter sp. SK1 was most efficiently spread along hyphae of hydrophilic F. oxysporum in both model systems with transport velocities of up to 1 cm d(-1), whereas no dispersion of the two nonmotile strains was observed in the presence of F. oxysporum. By contrast, none of the bacteria was mobilized along the hydrophobic mycelia of Rhexocercosporidium sp. growing on agar surfaces. In column experiments however, strain SK1 was mobilized by Rhexocercosporidium sp. It is hypothesized that bacteria may move by their intrinsic motilitythrough continuous (physiological) liquid films forming around fungal hyphae. The results of this study suggest that the specific stimulation of indigenous fungi may be a strategy to mobilize pollutant-degrading bacteria leading to their homogenization in polluted soil thereby improving bioremediation.
在模拟水饱和（琼脂表面）和非饱和土壤环境（填充玻璃珠的柱体）的实验室模型系统中，分析了真菌作为污染物降解细菌传播载体的能力。基于不存在相互拮抗作用，选择了两种常见的土壤真菌（尖孢镰刀菌和一种未知的尾孢菌属真菌），它们分别形成亲水性和疏水性菌丝体，以及三种多环芳烃降解细菌（无色杆菌属SK1菌株、弗雷德里克伯格分枝杆菌LB501TG菌株和鞘氨醇单胞菌属L138菌株）。结果表明，真菌菌丝体作为细菌运输的载体，其迁移强烈依赖于所选择的特定微生物：在两个模型系统中，运动性菌株无色杆菌属SK1菌株沿着亲水性尖孢镰刀菌的菌丝体最有效地传播，运输速度高达1厘米/天，而在尖孢镰刀菌存在的情况下，未观察到两种非运动性菌株的扩散。相比之下，在琼脂表面生长的尾孢菌属真菌的疏水菌丝体上，没有细菌被迁移。然而，在柱体实验中，SK1菌株被尾孢菌属真菌迁移。据推测，细菌可能通过其内在运动性，穿过在真菌菌丝体周围形成的连续（生理）液膜移动。这项研究的结果表明，特异性刺激本地真菌可能是一种促使污染物降解细菌迁移的策略，从而使它们在污染土壤中均匀分布，进而改善生物修复效果。
