Department of Biological Sciences, Kent State University, Kent, Ohio, USA.
Department of Food, Agricultural and Biological Engineering, Ohio State University, Columbus, Ohio, USA.
Environ Microbiol. 2023 Dec;25(12):3639-3654. doi: 10.1111/1462-2920.16529. Epub 2023 Oct 24.
In sediments, the bioavailability and toxicity of Ni are strongly influenced by its sorption to manganese (Mn) oxides, which largely originate from the redox metabolism of microbes. However, microbes are concurrently susceptible to the toxic effects of Ni, which establishes complex interactions between toxicity and redox processes. This study measured the effect of Ni on growth, pellicle biofilm formation and oxidation of the Mn-oxidizing bacteria Pseudomonas putida GB-1. In liquid media, Ni exposure decreased the intrinsic growth rate but allowed growth to the stationary phase in all intermediate treatments. Manganese oxidation was 67% less than control for bacteria exposed to 5 μM Ni and completely ceased in all treatments above 50 μM. Pellicle biofilm development decreased exponentially with Ni concentration (maximum 92% reduction) and was replaced by planktonic growth in higher Ni treatments. In solid media assays, growth was unaffected by Ni exposure, but Mn oxidation completely ceased in treatments above 10 μM of Ni. Our results show that sublethal Ni concentrations substantially alter Mn oxidation rates and pellicle biofilm development in P. putida GB-1, which has implications for toxic metal bioavailability to the entire benthic community and the environmental consequences of metal contamination.
在沉积物中，镍的生物利用度和毒性强烈受到其与锰 (Mn) 氧化物的吸附影响，而这些 Mn 氧化物主要来源于微生物的氧化还原代谢。然而，微生物同时易受到镍的毒性影响，这在毒性和氧化还原过程之间建立了复杂的相互作用。本研究测量了镍对锰氧化细菌 Pseudomonas putida GB-1 的生长、菌膜生物膜形成和氧化的影响。在液体培养基中，镍暴露降低了细菌的固有生长率，但在所有中间处理中都允许其进入静止期。与对照相比，暴露于 5 μM 镍的细菌的锰氧化减少了 67%，而在 50 μM 以上的所有处理中完全停止。菌膜生物膜的形成随镍浓度呈指数下降（最大减少 92%），在较高镍处理中被浮游生长所取代。在固体培养基测定中，镍暴露对生长没有影响，但在镍浓度高于 10 μM 的处理中，锰氧化完全停止。我们的结果表明，亚致死浓度的镍会显著改变 Pseudomonas putida GB-1 的锰氧化速率和菌膜生物膜的形成，这对整个底栖生物群落中有毒金属的生物利用度和金属污染的环境后果具有重要意义。
