Soil Amoebae Affect Iron and Chromium Reduction through Preferential Predation between Two Metal-Reducing Bacteria

• DOI: 10.1021/acs.est.1c08069
• Publication Date: 2022-05-11T20:07:45Z
• Authors: Huang Yu; Zhenzhen He; Zhili He; Qingyun Yan; Longfei Shu
• Keywords: Chromium; 0301 basic medicine; Iron; Hydrogen Peroxide; Soil; 03 medical and health sciences; Metals; Predatory Behavior; Animals; Dictyostelium; Amoeba; Oxidation-Reduction; Ecosystem

Soil protists are essential but often overlooked in soil and could impact microbially driven element cycling natural ecosystems. However, how influence heavy metal remains poorly understood. In this study, we used a model protist, Dictyostelium discoideum, to explore the effect of interactions between amoeba metal-reducing bacteria on reduction Fe(III) Cr(VI). We found that D. discoideum preferentially prey Fe(III)-reducing bacterium Shewanella decolorationis S12 significantly decrease its biomass. Surprisingly, predation pressure also stimulated activity single S. reduce by enhancing content electron-transfer protein cyt c, intracellular ATP synthesis, reactive oxygen species (e.g., H2O2). not Cr(VI)-reducing Brevibacillus laterosporus. contrast, B. laterosporus became edible amoebae presence S12, their Cr(VI) ability decreased under pressure. This study provides direct evidence can affect Cr Fe via elective bacteria, broadening our horizons cycling.